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/* ////////////////////////////////////////////////////////////////////
//
//  Geometrical transforms on images and matrices: rotation, zoom etc.
//
// */

#include "precomp.hpp"
#include "opencl_kernels_imgproc.hpp"
#include "hal_replacement.hpp"
#include "opencv2/core/hal/intrin.hpp"
#include "opencv2/core/utils/buffer_area.private.hpp"

#include "opencv2/core/openvx/ovx_defs.hpp"
#include "resize.hpp"

#include "opencv2/core/softfloat.hpp"
#include "fixedpoint.inl.hpp"

using namespace cv;

namespace
{

template <typename ET, bool needsign> struct fixedtype { typedef fixedpoint64 type; };
template <> struct fixedtype<uint32_t, false> { typedef ufixedpoint64 type; };
template <bool needsign> struct fixedtype<int16_t, needsign> { typedef fixedpoint32 type; };
template <> struct fixedtype<uint16_t, false> { typedef ufixedpoint32 type; };
template <bool needsign> struct fixedtype<int8_t, needsign> { typedef fixedpoint32 type; };
template <> struct fixedtype<uint8_t, false> { typedef ufixedpoint16 type; };

//FT is fixedtype<ET, needsign>::type
template <typename ET, typename FT, int n, bool mulall>
static void hlineResize(ET* src, int cn, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
{
    int i = 0;
    for (; i < dst_min; i++, m += n) // Points that fall left from src image so became equal to leftmost src point
    {
        for (int j = 0; j < cn; j++, dst++)
        {
            *dst = src[j];
        }
    }
    for (; i < dst_max; i++, m += n)
    {
        ET* src_ofst = src + cn*ofst[i];
        for (int j = 0; j < cn; j++, dst++)
        {
            *dst = (mulall || !m[0].isZero()) ? m[0] * src_ofst[j] : FT::zero();
            for (int k = 1; k < n; k++)
            {
                *dst = *dst + ((mulall || !m[k].isZero()) ? m[k] * src_ofst[j+k*cn] : FT::zero());
            }
        }
    }
    ET* src_last = src + cn*ofst[dst_width - 1];
    for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
    {
        for (int j = 0; j < cn; j++, dst++)
        {
            *dst = src_last[j];
        }
    }
}
template <typename ET, typename FT, int n, bool mulall, int cncnt> struct hline
{
    static void ResizeCn(ET* src, int cn, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        hlineResize<ET, FT, n, mulall>(src, cn, ofst, m, dst, dst_min, dst_max, dst_width);
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 2, true, 1>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]);
        for (; i < dst_min; i++, m += 2) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
        }
        for (; i < dst_max; i++, m += 2)
        {
            ET* px = src + ofst[i];
            *(dst++) = m[0] * px[0] + m[1] * px[1];
        }
        src0 = (src + ofst[dst_width - 1])[0];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 2, true, 2>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]), src1(src[1]);
        for (; i < dst_min; i++, m += 2) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
        }
        for (; i < dst_max; i++, m += 2)
        {
            ET* px = src + 2*ofst[i];
            *(dst++) = m[0] * px[0] + m[1] * px[2];
            *(dst++) = m[0] * px[1] + m[1] * px[3];
        }
        src0 = (src + 2*ofst[dst_width - 1])[0];
        src1 = (src + 2*ofst[dst_width - 1])[1];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 2, true, 3>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]), src1(src[1]), src2(src[2]);
        for (; i < dst_min; i++, m += 2) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
        }
        for (; i < dst_max; i++, m += 2)
        {
            ET* px = src + 3*ofst[i];
            *(dst++) = m[0] * px[0] + m[1] * px[3];
            *(dst++) = m[0] * px[1] + m[1] * px[4];
            *(dst++) = m[0] * px[2] + m[1] * px[5];
        }
        src0 = (src + 3*ofst[dst_width - 1])[0];
        src1 = (src + 3*ofst[dst_width - 1])[1];
        src2 = (src + 3*ofst[dst_width - 1])[2];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 2, true, 4>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]), src1(src[1]), src2(src[2]), src3(src[3]);
        for (; i < dst_min; i++, m += 2) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
            *(dst++) = src3;
        }
        for (; i < dst_max; i++, m += 2)
        {
            ET* px = src + 4*ofst[i];
            *(dst++) = m[0] * px[0] + m[1] * px[4];
            *(dst++) = m[0] * px[1] + m[1] * px[5];
            *(dst++) = m[0] * px[2] + m[1] * px[6];
            *(dst++) = m[0] * px[3] + m[1] * px[7];
        }
        src0 = (src + 4*ofst[dst_width - 1])[0];
        src1 = (src + 4*ofst[dst_width - 1])[1];
        src2 = (src + 4*ofst[dst_width - 1])[2];
        src3 = (src + 4*ofst[dst_width - 1])[3];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
            *(dst++) = src3;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 4, true, 1>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]);
        for (; i < dst_min; i++, m += 4) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
        }
        for (; i < dst_max; i++, m += 4)
        {
            ET* px = src + ofst[i];
            *(dst++) = m[0] * src[0] + m[1] * src[1] + m[2] * src[2] + m[3] * src[3];
        }
        src0 = (src + ofst[dst_width - 1])[0];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 4, true, 2>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]), src1(src[1]);
        for (; i < dst_min; i++, m += 4) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
        }
        for (; i < dst_max; i++, m += 4)
        {
            ET* px = src + 2*ofst[i];
            *(dst++) = m[0] * src[0] + m[1] * src[2] + m[2] * src[4] + m[3] * src[6];
            *(dst++) = m[0] * src[1] + m[1] * src[3] + m[2] * src[5] + m[3] * src[7];
        }
        src0 = (src + 2*ofst[dst_width - 1])[0];
        src1 = (src + 2*ofst[dst_width - 1])[1];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 4, true, 3>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]), src1(src[1]), src2(src[2]);
        for (; i < dst_min; i++, m += 4) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
        }
        for (; i < dst_max; i++, m += 4)
        {
            ET* px = src + 3*ofst[i];
            *(dst++) = m[0] * src[0] + m[1] * src[3] + m[2] * src[6] + m[3] * src[ 9];
            *(dst++) = m[0] * src[1] + m[1] * src[4] + m[2] * src[7] + m[3] * src[10];
            *(dst++) = m[0] * src[2] + m[1] * src[5] + m[2] * src[8] + m[3] * src[11];
        }
        src0 = (src + 3*ofst[dst_width - 1])[0];
        src1 = (src + 3*ofst[dst_width - 1])[1];
        src2 = (src + 3*ofst[dst_width - 1])[2];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
        }
    }
};
template <typename ET, typename FT> struct hline<ET, FT, 4, true, 4>
{
    static void ResizeCn(ET* src, int, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
    {
        int i = 0;
        FT src0(src[0]), src1(src[1]), src2(src[2]), src3(src[3]);
        for (; i < dst_min; i++, m += 4) // Points that fall left from src image so became equal to leftmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
            *(dst++) = src3;
        }
        for (; i < dst_max; i++, m += 4)
        {
            ET* px = src + 4*ofst[i];
            *(dst++) = m[0] * src[0] + m[1] * src[4] + m[2] * src[ 8] + m[3] * src[12];
            *(dst++) = m[0] * src[1] + m[1] * src[5] + m[2] * src[ 9] + m[3] * src[13];
            *(dst++) = m[0] * src[2] + m[1] * src[6] + m[2] * src[10] + m[3] * src[14];
            *(dst++) = m[0] * src[3] + m[1] * src[7] + m[2] * src[11] + m[3] * src[15];
        }
        src0 = (src + 4*ofst[dst_width - 1])[0];
        src1 = (src + 4*ofst[dst_width - 1])[1];
        src2 = (src + 4*ofst[dst_width - 1])[2];
        src3 = (src + 4*ofst[dst_width - 1])[3];
        for (; i < dst_width; i++) // Points that fall right from src image so became equal to rightmost src point
        {
            *(dst++) = src0;
            *(dst++) = src1;
            *(dst++) = src2;
            *(dst++) = src3;
        }
    }
};
template <typename ET, typename FT, int n, bool mulall, int cncnt>
static void hlineResizeCn(ET* src, int cn, int *ofst, FT* m, FT* dst, int dst_min, int dst_max, int dst_width)
{
    hline<ET, FT, n, mulall, cncnt>::ResizeCn(src, cn, ofst, m, dst, dst_min, dst_max, dst_width);
};

template <>
void hlineResizeCn<uint8_t, ufixedpoint16, 2, true, 1>(uint8_t* src, int, int *ofst, ufixedpoint16* m, ufixedpoint16* dst, int dst_min, int dst_max, int dst_width)
{
    int i = 0;
    ufixedpoint16 src_0(src[0]);
#if CV_SIMD
    const int VECSZ = v_uint16::nlanes;
    v_uint16 v_src_0 = vx_setall_u16(*((uint16_t*)&src_0));
    for (; i <= dst_min - VECSZ; i += VECSZ, m += 2*VECSZ, dst += VECSZ) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint16_t*)dst, v_src_0);
    }
#endif
    for (; i < dst_min; i++, m += 2)
    {
        *(dst++) = src_0;
    }
#if CV_SIMD
    for (; i <= dst_max - 2*VECSZ; i += 2*VECSZ, m += 4*VECSZ, dst += 2*VECSZ)
    {
        v_uint16 v_src0, v_src1;
        v_expand(vx_lut_pairs(src, ofst + i), v_src0, v_src1);
        v_store((uint16_t*)dst      , v_pack(v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src0), vx_load((int16_t*)m))),
                                             v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src1), vx_load((int16_t*)m + VECSZ)))));
        v_expand(vx_lut_pairs(src, ofst + i + VECSZ), v_src0, v_src1);
        v_store((uint16_t*)dst+VECSZ, v_pack(v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src0), vx_load((int16_t*)m + 2*VECSZ))),
                                             v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src1), vx_load((int16_t*)m + 3*VECSZ)))));
    }
    if (i <= dst_max - VECSZ)
    {
        v_uint16 v_src0, v_src1;
        v_expand(vx_lut_pairs(src, ofst + i), v_src0, v_src1);
        v_store((uint16_t*)dst, v_pack(v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src0), vx_load((int16_t*)m))),
                                       v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src1), vx_load((int16_t*)m + VECSZ)))));
        i += VECSZ; m += 2*VECSZ; dst += VECSZ;
    }
#endif
    for (; i < dst_max; i += 1, m += 2)
    {
        uint8_t* px = src + ofst[i];
        *(dst++) = m[0] * px[0] + m[1] * px[1];
    }
    src_0 = (src + ofst[dst_width - 1])[0];
#if CV_SIMD
    v_src_0 = vx_setall_u16(*((uint16_t*)&src_0));
    for (; i <= dst_width - VECSZ; i += VECSZ, dst += VECSZ) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint16_t*)dst, v_src_0);
    }
#endif
    for (; i < dst_width; i++)
    {
        *(dst++) = src_0;
    }
}
template <>
void hlineResizeCn<uint8_t, ufixedpoint16, 2, true, 2>(uint8_t* src, int, int *ofst, ufixedpoint16* m, ufixedpoint16* dst, int dst_min, int dst_max, int dst_width)
{
    int i = 0;
    union {
        uint32_t d;
        uint16_t w[2];
    } srccn;
    ((ufixedpoint16*)(srccn.w))[0] = src[0];
    ((ufixedpoint16*)(srccn.w))[1] = src[1];
#if CV_SIMD
    const int VECSZ = v_uint16::nlanes;
    v_uint16 v_srccn = v_reinterpret_as_u16(vx_setall_u32(srccn.d));
    for (; i <= dst_min - VECSZ/2; i += VECSZ/2, m += VECSZ, dst += VECSZ) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint16_t*)dst, v_srccn);
    }
#endif
    for (; i < dst_min; i++, m += 2)
    {
        *(dst++) = ((ufixedpoint16*)(srccn.w))[0];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[1];
    }
#if CV_SIMD
    for (; i <= dst_max - VECSZ/2; i += VECSZ/2, m += VECSZ, dst += VECSZ)
    {
        v_uint16 v_src0, v_src1;
        v_expand(v_interleave_pairs(v_reinterpret_as_u8(vx_lut_pairs((uint16_t*)src, ofst + i))), v_src0, v_src1);

        v_uint32 v_mul = vx_load((uint32_t*)m);//AaBbCcDd
        v_uint32 v_zip0, v_zip1;
        v_zip(v_mul, v_mul, v_zip0, v_zip1);//AaAaBbBb CcCcDdDd
        v_uint32 v_res0 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src0), v_reinterpret_as_s16(v_zip0)));
        v_uint32 v_res1 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src1), v_reinterpret_as_s16(v_zip1)));
        v_store((uint16_t*)dst, v_pack(v_res0, v_res1));//AB1AB2CD1CD2
    }
#endif
    for (; i < dst_max; i += 1, m += 2)
    {
        uint8_t* px = src + 2 * ofst[i];
        *(dst++) = m[0] * px[0] + m[1] * px[2];
        *(dst++) = m[0] * px[1] + m[1] * px[3];
    }
    ((ufixedpoint16*)(srccn.w))[0] = (src + 2 * ofst[dst_width - 1])[0]; ((ufixedpoint16*)(srccn.w))[1] = (src + 2 * ofst[dst_width - 1])[1];
#if CV_SIMD
    v_srccn = v_reinterpret_as_u16(vx_setall_u32(srccn.d));
    for (; i <= dst_width - VECSZ/2; i += VECSZ/2, dst += VECSZ) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint16_t*)dst, v_srccn);
    }
#endif
    for (; i < dst_width; i++)
    {
        *(dst++) = ((ufixedpoint16*)(srccn.w))[0];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[1];
    }
}
template <>
void hlineResizeCn<uint8_t, ufixedpoint16, 2, true, 3>(uint8_t* src, int, int *ofst, ufixedpoint16* m, ufixedpoint16* dst, int dst_min, int dst_max, int dst_width)
{
    int i = 0;
    union {
        uint64_t q;
        uint16_t w[4];
    } srccn;
    ((ufixedpoint16*)(srccn.w))[0] = src[0];
    ((ufixedpoint16*)(srccn.w))[1] = src[1];
    ((ufixedpoint16*)(srccn.w))[2] = src[2];
    ((ufixedpoint16*)(srccn.w))[3] = 0;
#if CV_SIMD
    const int VECSZ = v_uint16::nlanes;
    v_uint16 v_srccn = v_pack_triplets(v_reinterpret_as_u16(vx_setall_u64(srccn.q)));
    for (; i <= dst_min - (VECSZ+2)/3; i += VECSZ/4, m += VECSZ/2, dst += 3*VECSZ/4) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint16_t*)dst, v_srccn);
    }
#endif
    for (; i < dst_min; i++, m += 2)
    {
        *(dst++) = ((ufixedpoint16*)(srccn.w))[0];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[1];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[2];
    }
#if CV_SIMD
    CV_DECL_ALIGNED(CV_SIMD_WIDTH) int ofst3[VECSZ/2];
    for (; i <= dst_max - (3*VECSZ/4 + (VECSZ+2)/3); i += VECSZ/2, m += VECSZ, dst += 3*VECSZ/2)
    {
        v_store(ofst3, vx_load(ofst + i) * vx_setall_s32(3));
        v_uint8 v_src01, v_src23;
        v_uint16 v_src0, v_src1, v_src2, v_src3;
        v_zip(vx_lut_quads(src, ofst3), v_reinterpret_as_u8(v_reinterpret_as_u32(vx_lut_quads(src+2, ofst3)) >> 8), v_src01, v_src23);
        v_expand(v_src01, v_src0, v_src1);
        v_expand(v_src23, v_src2, v_src3);

        v_uint32 v_mul0, v_mul1, v_mul2, v_mul3, v_tmp;
        v_mul0 = vx_load((uint32_t*)m);//AaBbCcDd
        v_zip(v_mul0, v_mul0, v_mul3, v_tmp );//AaAaBbBb CcCcDdDd
        v_zip(v_mul3, v_mul3, v_mul0, v_mul1);//AaAaAaAa BbBbBbBb
        v_zip(v_tmp , v_tmp , v_mul2, v_mul3);//CcCcCcCc DdDdDdDd

        v_uint32 v_res0 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src0), v_reinterpret_as_s16(v_mul0)));
        v_uint32 v_res1 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src1), v_reinterpret_as_s16(v_mul1)));
        v_uint32 v_res2 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src2), v_reinterpret_as_s16(v_mul2)));
        v_uint32 v_res3 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src3), v_reinterpret_as_s16(v_mul3)));
        v_store((uint16_t*)dst            , v_pack_triplets(v_pack(v_res0, v_res1)));
        v_store((uint16_t*)dst + 3*VECSZ/4, v_pack_triplets(v_pack(v_res2, v_res3)));
    }
#endif
    for (; i < dst_max; i += 1, m += 2)
    {
        uint8_t* px = src + 3 * ofst[i];
        *(dst++) = m[0] * px[0] + m[1] * px[3];
        *(dst++) = m[0] * px[1] + m[1] * px[4];
        *(dst++) = m[0] * px[2] + m[1] * px[5];
    }
    ((ufixedpoint16*)(srccn.w))[0] = (src + 3*ofst[dst_width - 1])[0];
    ((ufixedpoint16*)(srccn.w))[1] = (src + 3*ofst[dst_width - 1])[1];
    ((ufixedpoint16*)(srccn.w))[2] = (src + 3*ofst[dst_width - 1])[2];
#if CV_SIMD
    v_srccn = v_pack_triplets(v_reinterpret_as_u16(vx_setall_u64(srccn.q)));
    for (; i <= dst_width - (VECSZ+2)/3; i += VECSZ/4, dst += 3*VECSZ/4) // Points that fall right from src image so became equal to rightmost src point
    {
        v_store((uint16_t*)dst, v_srccn);
    }
#endif
    for (; i < dst_width; i++)
    {
        *(dst++) = ((ufixedpoint16*)(srccn.w))[0];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[1];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[2];
    }
}
template <>
void hlineResizeCn<uint8_t, ufixedpoint16, 2, true, 4>(uint8_t* src, int, int *ofst, ufixedpoint16* m, ufixedpoint16* dst, int dst_min, int dst_max, int dst_width)
{
    int i = 0;
    union {
        uint64_t q;
        uint16_t w[4];
    } srccn;
    ((ufixedpoint16*)(srccn.w))[0] = src[0];
    ((ufixedpoint16*)(srccn.w))[1] = src[1];
    ((ufixedpoint16*)(srccn.w))[2] = src[2];
    ((ufixedpoint16*)(srccn.w))[3] = src[3];
#if CV_SIMD
    const int VECSZ = v_uint16::nlanes;
    v_uint16 v_srccn = v_reinterpret_as_u16(vx_setall_u64(srccn.q));
    for (; i <= dst_min - VECSZ/4; i += VECSZ/4, m += VECSZ/2, dst += VECSZ) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint16_t*)dst, v_srccn);
    }
#endif
    for (; i < dst_min; i++, m += 2)
    {
        *(dst++) = ((ufixedpoint16*)(srccn.w))[0];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[1];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[2];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[3];
    }
#if CV_SIMD
    for (; i <= dst_max - VECSZ/2; i += VECSZ/2, m += VECSZ, dst += 2*VECSZ)
    {
        v_uint16 v_src0, v_src1, v_src2, v_src3;
        v_expand(v_interleave_quads(v_reinterpret_as_u8(vx_lut_pairs((uint32_t*)src, ofst + i))), v_src0, v_src1);
        v_expand(v_interleave_quads(v_reinterpret_as_u8(vx_lut_pairs((uint32_t*)src, ofst + i + VECSZ/4))), v_src2, v_src3);

        v_uint32 v_mul0, v_mul1, v_mul2, v_mul3, v_tmp;
        v_mul0 = vx_load((uint32_t*)m);//AaBbCcDd
        v_zip(v_mul0, v_mul0, v_mul3, v_tmp );//AaAaBbBb CcCcDdDd
        v_zip(v_mul3, v_mul3, v_mul0, v_mul1);//AaAaAaAa BbBbBbBb
        v_zip(v_tmp , v_tmp , v_mul2, v_mul3);//CcCcCcCc DdDdDdDd

        v_uint32 v_res0 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src0), v_reinterpret_as_s16(v_mul0)));
        v_uint32 v_res1 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src1), v_reinterpret_as_s16(v_mul1)));
        v_uint32 v_res2 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src2), v_reinterpret_as_s16(v_mul2)));
        v_uint32 v_res3 = v_reinterpret_as_u32(v_dotprod(v_reinterpret_as_s16(v_src3), v_reinterpret_as_s16(v_mul3)));
        v_store((uint16_t*)dst        , v_pack(v_res0, v_res1));
        v_store((uint16_t*)dst + VECSZ, v_pack(v_res2, v_res3));
    }
#endif
    for (; i < dst_max; i += 1, m += 2)
    {
        uint8_t* px = src + 4 * ofst[i];
        *(dst++) = m[0] * px[0] + m[1] * px[4];
        *(dst++) = m[0] * px[1] + m[1] * px[5];
        *(dst++) = m[0] * px[2] + m[1] * px[6];
        *(dst++) = m[0] * px[3] + m[1] * px[7];
    }
    ((ufixedpoint16*)(srccn.w))[0] = (src + 4 * ofst[dst_width - 1])[0]; ((ufixedpoint16*)(srccn.w))[1] = (src + 4 * ofst[dst_width - 1])[1];
    ((ufixedpoint16*)(srccn.w))[2] = (src + 4 * ofst[dst_width - 1])[2]; ((ufixedpoint16*)(srccn.w))[3] = (src + 4 * ofst[dst_width - 1])[3];
#if CV_SIMD
    v_srccn = v_reinterpret_as_u16(vx_setall_u64(srccn.q));
    for (; i <= dst_width - VECSZ/4; i += VECSZ/4, dst += VECSZ) // Points that fall right from src image so became equal to rightmost src point
    {
        v_store((uint16_t*)dst, v_srccn);
    }
#endif
    for (; i < dst_width; i++)
    {
        *(dst++) = ((ufixedpoint16*)(srccn.w))[0];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[1];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[2];
        *(dst++) = ((ufixedpoint16*)(srccn.w))[3];
    }
}
template <>
void hlineResizeCn<uint16_t, ufixedpoint32, 2, true, 1>(uint16_t* src, int, int *ofst, ufixedpoint32* m, ufixedpoint32* dst, int dst_min, int dst_max, int dst_width)
{
    int i = 0;
    ufixedpoint32 src_0(src[0]);
#if CV_SIMD
    const int VECSZ = v_uint32::nlanes;
    v_uint32 v_src_0 = vx_setall_u32(*((uint32_t*)&src_0));
    for (; i <= dst_min - VECSZ; i += VECSZ, m += 2*VECSZ, dst += VECSZ) // Points that fall left from src image so became equal to leftmost src point
    {
        v_store((uint32_t*)dst, v_src_0);
    }
#endif
    for (; i < dst_min; i++, m += 2)
    {
        *(dst++) = src_0;
    }
#if CV_SIMD
    for (; i <= dst_max - VECSZ; i += VECSZ, m += 2*VECSZ, dst += VECSZ)
    {
        v_uint32 v_src0, v_src1;
        v_expand(vx_lut_pairs(src, ofst + i), v_src0, v_src1);

        v_uint64 v_res0 = v_reinterpret_as_u64(v_src0 * vx_load((uint32_t*)m));
        v_uint64 v_res1 = v_reinterpret_as_u64(v_src1 * vx_load((uint32_t*)m + VECSZ));
        v_store((uint32_t*)dst, v_pack((v_res0 & vx_setall_u64(0xFFFFFFFF)) + (v_res0 >> 32),
                                       (v_res1 & vx_setall_u64(0xFFFFFFFF)) + (v_res1 >> 32)));
    }
#endif
    for (; i < dst_max; i += 1, m += 2)
    {
        uint16_t* px = src + ofst[i];
        *(dst++) = m[0] * px[0] + m[1] * px[1];
    }
    src_0 = (src + ofst[dst_width - 1])[0];
#if CV_SIMD
    v_src_0 = vx_setall_u32(*((uint32_t*)&src_0));
    for (; i <= dst_width - VECSZ; i += VECSZ, dst += VECSZ)
    {
        v_store((uint32_t*)dst, v_src_0);
    }
#endif
    for (; i < dst_width; i++)
    {
        *(dst++) = src_0;
    }
}

template <typename ET, typename FT>
void vlineSet(FT* src, ET* dst, int dst_width)
{
    for (int i = 0; i < dst_width; i++)
        dst[i] = src[i];
}
template <>
void vlineSet<uint8_t, ufixedpoint16>(ufixedpoint16* src, uint8_t* dst, int dst_width)
{
    int i = 0;
#if CV_SIMD
    const int VECSZ = v_uint8::nlanes;
    static const v_uint16 v_fixedRound = vx_setall_u16((uint16_t)((1U << 8) >> 1));
    for (; i <= dst_width - VECSZ; i += VECSZ, src += VECSZ, dst += VECSZ)
    {
        v_uint16 v_src0 = vx_load((uint16_t*)src);
        v_uint16 v_src1 = vx_load((uint16_t*)src + VECSZ/2);

        v_uint16 v_res0 = (v_src0 + v_fixedRound) >> 8;
        v_uint16 v_res1 = (v_src1 + v_fixedRound) >> 8;

        v_store(dst, v_pack(v_res0, v_res1));
    }
#endif
    for (; i < dst_width; i++)
        *(dst++) = *(src++);
}

template <typename ET, typename FT, int n>
void vlineResize(FT* src, size_t src_step, FT* m, ET* dst, int dst_width)
{
    for (int i = 0; i < dst_width; i++)
    {
        typename FT::WT res = src[i] * m[0];
        for (int k = 1; k < n; k++)
            res = res + src[i + k*src_step] * m[k];
        dst[i] = res;
    }
}
template <>
void vlineResize<uint8_t, ufixedpoint16, 2>(ufixedpoint16* src, size_t src_step, ufixedpoint16* m, uint8_t* dst, int dst_width)
{
    int i = 0;
    ufixedpoint16* src1 = src + src_step;
#if CV_SIMD
    const int VECSZ = v_uint8::nlanes;
    static const v_int32 v_fixedRound = vx_setall_s32((int32_t)((1 << 16) >> 1));
    static const v_int16 v_128    = v_reinterpret_as_s16(vx_setall_u16((uint16_t)1<<15));
    static const v_int8  v_128_16 = v_reinterpret_as_s8 (vx_setall_u8 ((uint8_t) 1<<7));

    v_int16 v_mul = v_reinterpret_as_s16(vx_setall_u32(((uint32_t*)m)[0]));
    for (; i <= dst_width - VECSZ; i += VECSZ, src += VECSZ, src1 += VECSZ, dst += VECSZ)
    {
        v_int16 v_src00 = vx_load((int16_t*)src);
        v_int16 v_src10 = vx_load((int16_t*)src1);
        v_int16 v_tmp0, v_tmp1;
        v_zip(v_add_wrap(v_src00,v_128), v_add_wrap(v_src10,v_128), v_tmp0, v_tmp1);

        v_int32 v_res0 = v_dotprod(v_tmp0, v_mul);
        v_int32 v_res1 = v_dotprod(v_tmp1, v_mul);

        v_int16 v_src01 = vx_load((int16_t*)src + VECSZ/2);
        v_int16 v_src11 = vx_load((int16_t*)src1 + VECSZ/2);
        v_zip(v_add_wrap(v_src01,v_128), v_add_wrap(v_src11,v_128), v_tmp0, v_tmp1);
        v_int32 v_res2 = v_dotprod(v_tmp0, v_mul);
        v_int32 v_res3 = v_dotprod(v_tmp1, v_mul);

        v_int8 v_res = v_pack(v_pack((v_res0 + v_fixedRound) >> 16,
                                     (v_res1 + v_fixedRound) >> 16),
                              v_pack((v_res2 + v_fixedRound) >> 16,
                                     (v_res3 + v_fixedRound) >> 16));

        v_store(dst, v_reinterpret_as_u8(v_sub_wrap(v_res, v_128_16)));
    }
#endif
    for (; i < dst_width; i++)
    {
        *(dst++) = (uint8_t)(*(src++) * m[0] + *(src1++) * m[1]);
    }
}

template <typename ET> class interpolationLinear
{
public:
    static const int len = 2;
    static const bool needsign = false;
    interpolationLinear(double inv_scale, int srcsize, int dstsize) : scale(softdouble::one() / softdouble(inv_scale)), maxsize(srcsize), minofst(0), maxofst(dstsize) {}
    void getCoeffs(int val, int* offset, typename fixedtype<ET, needsign>::type* coeffs)
    {
        typedef typename fixedtype<ET, needsign>::type fixedpoint;
        softdouble fval = scale*(softdouble(val)+softdouble(0.5))-softdouble(0.5);
        int ival = cvFloor(fval);
        if (ival >= 0 && maxsize > 1)
        {
            if (ival < maxsize - 1)
            {
                *offset = ival;
                coeffs[1] = fval - softdouble(ival);
                coeffs[0] = fixedpoint::one() - coeffs[1];
            }
            else
            {
                *offset = maxsize - 1;
                maxofst = min(maxofst, val);
            }
        }
        else
        {
            minofst = max(minofst, val + 1);
        }
    }
    void getMinMax(int &min, int &max)
    {
        min = minofst;
        max = maxofst;
    }
protected:
    softdouble scale;
    int maxsize;
    int minofst, maxofst;
};

template <typename ET, typename FT, int interp_y_len>
class resize_bitExactInvoker :
    public ParallelLoopBody
{
public:
    typedef FT fixedpoint;
    typedef void(*hResizeFunc)(ET* src, int cn, int *ofst, fixedpoint* m, fixedpoint* dst, int dst_min, int dst_max, int dst_width);
    resize_bitExactInvoker(const uchar* _src, size_t _src_step, int _src_width, int _src_height,
                           uchar* _dst, size_t _dst_step, int _dst_width, int _dst_height,
                           int _cn, int *_xoffsets, int *_yoffsets, fixedpoint *_xcoeffs, fixedpoint *_ycoeffs,
                           int _min_x, int _max_x, int _min_y, int _max_y, hResizeFunc _hResize) : ParallelLoopBody(),
                           src(_src), src_step(_src_step), src_width(_src_width), src_height(_src_height),
                           dst(_dst), dst_step(_dst_step), dst_width(_dst_width), dst_height(_dst_height),
                           cn(_cn), xoffsets(_xoffsets), yoffsets(_yoffsets), xcoeffs(_xcoeffs), ycoeffs(_ycoeffs),
                           min_x(_min_x), max_x(_max_x), min_y(_min_y), max_y(_max_y), hResize(_hResize) {}

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        AutoBuffer<fixedpoint> linebuf(interp_y_len * dst_width * cn);
        int last_eval = - interp_y_len;
        int evalbuf_start = 0;
        int rmin_y = max(min_y, range.start);
        int rmax_y = min(max_y, range.end);
        if (range.start < min_y)
        {
            last_eval = 1 - interp_y_len;
            evalbuf_start = 1;
            hResize((ET*)src, cn, xoffsets, xcoeffs, linebuf.data(), min_x, max_x, dst_width);
        }
        int dy = range.start;
        for (; dy < rmin_y; dy++)
            vlineSet<ET, FT>(linebuf.data(), (ET*)(dst + dst_step * dy), dst_width*cn);
        for (; dy < rmax_y; dy++)
        {
            int &iy = yoffsets[dy];

            int i;
            for (i = max(iy, last_eval + interp_y_len); i < min(iy + interp_y_len, src_height); i++, evalbuf_start = (evalbuf_start + 1) % interp_y_len)
                hResize((ET*)(src + i * src_step), cn, xoffsets, xcoeffs, linebuf.data() + evalbuf_start*(dst_width * cn), min_x, max_x, dst_width);
            evalbuf_start = (evalbuf_start + max(iy, src_height - interp_y_len) - max(last_eval, src_height - interp_y_len)) % interp_y_len;
            last_eval = iy;

            fixedpoint curcoeffs[interp_y_len];
            for (i = 0; i < evalbuf_start; i++)
                curcoeffs[i] = ycoeffs[ dy*interp_y_len - evalbuf_start + interp_y_len + i];
            for (; i < interp_y_len; i++)
                curcoeffs[i] = ycoeffs[ dy*interp_y_len - evalbuf_start + i];

            vlineResize<ET, FT, interp_y_len>(linebuf.data(), dst_width*cn, curcoeffs, (ET*)(dst + dst_step * dy), dst_width*cn);
        }
        fixedpoint *endline = linebuf.data();
        if (last_eval + interp_y_len > src_height)
            endline += dst_width*cn*((evalbuf_start + src_height - 1 - last_eval) % interp_y_len);
        else
            hResize((ET*)(src + (src_height - 1) * src_step), cn, xoffsets, xcoeffs, endline, min_x, max_x, dst_width);
        for (; dy < range.end; dy++)
            vlineSet<ET, FT>(endline, (ET*)(dst + dst_step * dy), dst_width*cn);
#if CV_SIMD
        vx_cleanup();
#endif
    }

private:
    const uchar* src;
    size_t src_step;
    int src_width, src_height;
    uchar* dst;
    size_t dst_step;
    int dst_width, dst_height, cn;
    int *xoffsets, *yoffsets;
    fixedpoint *xcoeffs, *ycoeffs;
    int min_x, max_x, min_y, max_y;
    hResizeFunc hResize;

    resize_bitExactInvoker(const resize_bitExactInvoker&);
    resize_bitExactInvoker& operator=(const resize_bitExactInvoker&);
};

template <typename ET, typename interpolation>
void resize_bitExact(const uchar* src, size_t src_step, int src_width, int src_height,
                           uchar* dst, size_t dst_step, int dst_width, int dst_height,
                     int cn, double inv_scale_x, double inv_scale_y)
{
    typedef typename fixedtype<ET, interpolation::needsign>::type fixedpoint;
    void(*hResize)(ET* src, int cn, int *ofst, fixedpoint* m, fixedpoint* dst, int dst_min, int dst_max, int dst_width);
    switch (cn)
    {
    case  1: hResize = src_width > interpolation::len ? hlineResizeCn<ET, fixedpoint, interpolation::len, true, 1> : hlineResizeCn<ET, fixedpoint, interpolation::len, false, 1>; break;
    case  2: hResize = src_width > interpolation::len ? hlineResizeCn<ET, fixedpoint, interpolation::len, true, 2> : hlineResizeCn<ET, fixedpoint, interpolation::len, false, 2>; break;
    case  3: hResize = src_width > interpolation::len ? hlineResizeCn<ET, fixedpoint, interpolation::len, true, 3> : hlineResizeCn<ET, fixedpoint, interpolation::len, false, 3>; break;
    case  4: hResize = src_width > interpolation::len ? hlineResizeCn<ET, fixedpoint, interpolation::len, true, 4> : hlineResizeCn<ET, fixedpoint, interpolation::len, false, 4>; break;
    default: hResize = src_width > interpolation::len ? hlineResize<ET, fixedpoint, interpolation::len, true>      : hlineResize<ET, fixedpoint, interpolation::len, false>     ; break;
    }

    interpolation interp_x(inv_scale_x, src_width, dst_width);
    interpolation interp_y(inv_scale_y, src_height, dst_height);

    AutoBuffer<uchar> buf( dst_width * sizeof(int) +
                           dst_height * sizeof(int) +
                           dst_width * interp_x.len*sizeof(fixedpoint) +
                           dst_height * interp_y.len * sizeof(fixedpoint) );
    int* xoffsets = (int*)buf.data();
    int* yoffsets = xoffsets + dst_width;
    fixedpoint* xcoeffs = (fixedpoint*)(yoffsets + dst_height);
    fixedpoint* ycoeffs = xcoeffs + dst_width * interp_x.len;

    int min_x, max_x, min_y, max_y;
    for (int dx = 0; dx < dst_width; dx++)
        interp_x.getCoeffs(dx, xoffsets+dx, xcoeffs+dx*interp_x.len);
    interp_x.getMinMax(min_x, max_x);
    for (int dy = 0; dy < dst_height; dy++)
        interp_y.getCoeffs(dy, yoffsets+dy, ycoeffs+dy*interp_y.len);
    interp_y.getMinMax(min_y, max_y);

    resize_bitExactInvoker<ET, fixedpoint, interpolation::len> invoker(src, src_step, src_width, src_height, dst, dst_step, dst_width, dst_height, cn,
                                                                       xoffsets, yoffsets, xcoeffs, ycoeffs, min_x, max_x, min_y, max_y, hResize);
    Range range(0, dst_height);
    parallel_for_(range, invoker, dst_width * dst_height / (double)(1 << 16));
}

typedef void(*be_resize_func)(const uchar* src, size_t src_step, int src_width, int src_height,
                                    uchar* dst, size_t dst_step, int dst_width, int dst_height,
                              int cn, double inv_scale_x, double inv_scale_y);

}

namespace cv
{

/************** interpolation formulas and tables ***************/

const int INTER_RESIZE_COEF_BITS=11;
const int INTER_RESIZE_COEF_SCALE=1 << INTER_RESIZE_COEF_BITS;

static inline void interpolateCubic( float x, float* coeffs )
{
    const float A = -0.75f;

    coeffs[0] = ((A*(x + 1) - 5*A)*(x + 1) + 8*A)*(x + 1) - 4*A;
    coeffs[1] = ((A + 2)*x - (A + 3))*x*x + 1;
    coeffs[2] = ((A + 2)*(1 - x) - (A + 3))*(1 - x)*(1 - x) + 1;
    coeffs[3] = 1.f - coeffs[0] - coeffs[1] - coeffs[2];
}

static inline void interpolateLanczos4( float x, float* coeffs )
{
    static const double s45 = 0.70710678118654752440084436210485;
    static const double cs[][2]=
    {{1, 0}, {-s45, -s45}, {0, 1}, {s45, -s45}, {-1, 0}, {s45, s45}, {0, -1}, {-s45, s45}};

    float sum = 0;
    double y0=-(x+3)*CV_PI*0.25, s0 = std::sin(y0), c0= std::cos(y0);
    for(int i = 0; i < 8; i++ )
    {
        float y0_ = (x+3-i);
        if (fabs(y0_) >= 1e-6f)
        {
            double y = -y0_*CV_PI*0.25;
            coeffs[i] = (float)((cs[i][0]*s0 + cs[i][1]*c0)/(y*y));
        }
        else
        {
            // special handling for 'x' values:
            // - ~0.0: 0 0 0 1 0 0 0 0
            // - ~1.0: 0 0 0 0 1 0 0 0
            coeffs[i] = 1e30f;
        }
        sum += coeffs[i];
    }

    sum = 1.f/sum;
    for(int i = 0; i < 8; i++ )
        coeffs[i] *= sum;
}

template<typename ST, typename DT> struct Cast
{
    typedef ST type1;
    typedef DT rtype;

    DT operator()(ST val) const { return saturate_cast<DT>(val); }
};

template<typename ST, typename DT, int bits> struct FixedPtCast
{
    typedef ST type1;
    typedef DT rtype;
    enum { SHIFT = bits, DELTA = 1 << (bits-1) };

    DT operator()(ST val) const { return saturate_cast<DT>((val + DELTA)>>SHIFT); }
};

/****************************************************************************************\
*                                         Resize                                         *
\****************************************************************************************/

class resizeNNInvoker :
    public ParallelLoopBody
{
public:
    resizeNNInvoker(const Mat& _src, Mat &_dst, int *_x_ofs, double _ify) :
        ParallelLoopBody(), src(_src), dst(_dst), x_ofs(_x_ofs),
        ify(_ify)
    {
    }

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        Size ssize = src.size(), dsize = dst.size();
        int y, x, pix_size = (int)src.elemSize();

        for( y = range.start; y < range.end; y++ )
        {
            uchar* D = dst.data + dst.step*y;
            int sy = std::min(cvFloor(y*ify), ssize.height-1);
            const uchar* S = src.ptr(sy);

            switch( pix_size )
            {
            case 1:
                for( x = 0; x <= dsize.width - 2; x += 2 )
                {
                    uchar t0 = S[x_ofs[x]];
                    uchar t1 = S[x_ofs[x+1]];
                    D[x] = t0;
                    D[x+1] = t1;
                }

                for( ; x < dsize.width; x++ )
                    D[x] = S[x_ofs[x]];
                break;
            case 2:
                for( x = 0; x < dsize.width; x++ )
                    *(ushort*)(D + x*2) = *(ushort*)(S + x_ofs[x]);
                break;
            case 3:
                for( x = 0; x < dsize.width; x++, D += 3 )
                {
                    const uchar* _tS = S + x_ofs[x];
                    D[0] = _tS[0]; D[1] = _tS[1]; D[2] = _tS[2];
                }
                break;
            case 4:
                for( x = 0; x < dsize.width; x++ )
                    *(int*)(D + x*4) = *(int*)(S + x_ofs[x]);
                break;
            case 6:
                for( x = 0; x < dsize.width; x++, D += 6 )
                {
                    const ushort* _tS = (const ushort*)(S + x_ofs[x]);
                    ushort* _tD = (ushort*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1]; _tD[2] = _tS[2];
                }
                break;
            case 8:
                for( x = 0; x < dsize.width; x++, D += 8 )
                {
                    const int* _tS = (const int*)(S + x_ofs[x]);
                    int* _tD = (int*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1];
                }
                break;
            case 12:
                for( x = 0; x < dsize.width; x++, D += 12 )
                {
                    const int* _tS = (const int*)(S + x_ofs[x]);
                    int* _tD = (int*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1]; _tD[2] = _tS[2];
                }
                break;
            default:
                for( x = 0; x < dsize.width; x++, D += pix_size )
                {
                    const uchar* _tS = S + x_ofs[x];
                    for (int k = 0; k < pix_size; k++)
                        D[k] = _tS[k];
                }
            }
        }
    }

private:
    const Mat& src;
    Mat& dst;
    int* x_ofs;
    double ify;

    resizeNNInvoker(const resizeNNInvoker&);
    resizeNNInvoker& operator=(const resizeNNInvoker&);
};

static void
resizeNN( const Mat& src, Mat& dst, double fx, double fy )
{
    Size ssize = src.size(), dsize = dst.size();
    AutoBuffer<int> _x_ofs(dsize.width);
    int* x_ofs = _x_ofs.data();
    int pix_size = (int)src.elemSize();
    double ifx = 1./fx, ify = 1./fy;
    int x;

    for( x = 0; x < dsize.width; x++ )
    {
        int sx = cvFloor(x*ifx);
        x_ofs[x] = std::min(sx, ssize.width-1)*pix_size;
    }

    Range range(0, dsize.height);
#if CV_TRY_AVX2
    if(CV_CPU_HAS_SUPPORT_AVX2 && ((pix_size == 2) || (pix_size == 4)))
    {
        if(pix_size == 2)
            opt_AVX2::resizeNN2_AVX2(range, src, dst, x_ofs, ify);
        else
            opt_AVX2::resizeNN4_AVX2(range, src, dst, x_ofs, ify);
    }
    else
#endif
#if CV_TRY_SSE4_1
    if(CV_CPU_HAS_SUPPORT_SSE4_1 && ((pix_size == 2) || (pix_size == 4)))
    {
        if(pix_size == 2)
            opt_SSE4_1::resizeNN2_SSE4_1(range, src, dst, x_ofs, ify);
        else
            opt_SSE4_1::resizeNN4_SSE4_1(range, src, dst, x_ofs, ify);
    }
    else
#endif
    {
        resizeNNInvoker invoker(src, dst, x_ofs, ify);
        parallel_for_(range, invoker, dst.total()/(double)(1<<16));
    }
}

class resizeNN_bitexactInvoker : public ParallelLoopBody
{
public:
    resizeNN_bitexactInvoker(const Mat& _src, Mat& _dst, int* _x_ofse, int _ify, int _ify0)
        : src(_src), dst(_dst), x_ofse(_x_ofse), ify(_ify), ify0(_ify0) {}

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        Size ssize = src.size(), dsize = dst.size();
        int pix_size = (int)src.elemSize();
        for( int y = range.start; y < range.end; y++ )
        {
            uchar* D = dst.ptr(y);
            int _sy = (ify * y + ify0) >> 16;
            int sy = std::min(_sy, ssize.height-1);
            const uchar* S = src.ptr(sy);

            int x = 0;
            switch( pix_size )
            {
            case 1:
#if CV_SIMD
                for( ; x <= dsize.width - v_uint8::nlanes; x += v_uint8::nlanes )
                    v_store(D + x, vx_lut(S, x_ofse + x));
#endif
                for( ; x < dsize.width; x++ )
                    D[x] = S[x_ofse[x]];
                break;
            case 2:
#if CV_SIMD
                for( ; x <= dsize.width - v_uint16::nlanes; x += v_uint16::nlanes )
                    v_store((ushort*)D + x, vx_lut((ushort*)S, x_ofse + x));
#endif
                for( ; x < dsize.width; x++ )
                    *((ushort*)D + x) = *((ushort*)S + x_ofse[x]);
                break;
            case 3:
                for( ; x < dsize.width; x++, D += 3 )
                {
                    const uchar* _tS = S + x_ofse[x] * 3;
                    D[0] = _tS[0]; D[1] = _tS[1]; D[2] = _tS[2];
                }
                break;
            case 4:
#if CV_SIMD
                for( ; x <= dsize.width - v_uint32::nlanes; x += v_uint32::nlanes )
                    v_store((uint32_t*)D + x, vx_lut((uint32_t*)S, x_ofse + x));
#endif
                for( ; x < dsize.width; x++ )
                    *((uint32_t*)D + x) = *((uint32_t*)S + x_ofse[x]);
                break;
            case 6:
                for( ; x < dsize.width; x++, D += 6 )
                {
                    const ushort* _tS = (const ushort*)(S + x_ofse[x]*6);
                    ushort* _tD = (ushort*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1]; _tD[2] = _tS[2];
                }
                break;
            case 8:
#if CV_SIMD
                for( ; x <= dsize.width - v_uint64::nlanes; x += v_uint64::nlanes )
                    v_store((uint64_t*)D + x, vx_lut((uint64_t*)S, x_ofse + x));
#endif
                for( ; x < dsize.width; x++ )
                    *((uint64_t*)D + x) = *((uint64_t*)S + x_ofse[x]);
                break;
            case 12:
                for( ; x < dsize.width; x++, D += 12 )
                {
                    const int* _tS = (const int*)(S + x_ofse[x]*12);
                    int* _tD = (int*)D;
                    _tD[0] = _tS[0]; _tD[1] = _tS[1]; _tD[2] = _tS[2];
                }
                break;
            default:
                for( x = 0; x < dsize.width; x++, D += pix_size )
                {
                    const uchar* _tS = S + x_ofse[x] * pix_size;
                    for (int k = 0; k < pix_size; k++)
                        D[k] = _tS[k];
                }
            }
        }
    }
private:
    const Mat& src;
    Mat& dst;
    int* x_ofse;
    const int ify;
    const int ify0;
};

static void resizeNN_bitexact( const Mat& src, Mat& dst, double /*fx*/, double /*fy*/ )
{
    Size ssize = src.size(), dsize = dst.size();
    int ifx = ((ssize.width << 16) + dsize.width / 2) / dsize.width; // 16bit fixed-point arithmetic
    int ifx0 = ifx / 2 - 1;                                     // This method uses center pixel coordinate as Pillow and scikit-images do.
    int ify = ((ssize.height << 16) + dsize.height / 2) / dsize.height;
    int ify0 = ify / 2 - 1;

    cv::utils::BufferArea area;
    int* x_ofse = 0;
    area.allocate(x_ofse, dsize.width, CV_SIMD_WIDTH);
    area.commit();

    for( int x = 0; x < dsize.width; x++ )
    {
        int sx = (ifx * x + ifx0) >> 16;
        x_ofse[x] = std::min(sx, ssize.width-1);    // offset in element (not byte)
    }
    Range range(0, dsize.height);
    resizeNN_bitexactInvoker invoker(src, dst, x_ofse, ify, ify0);
    parallel_for_(range, invoker, dst.total()/(double)(1<<16));
}

struct VResizeNoVec
{
    template<typename WT, typename T, typename BT>
    int operator()(const WT**, T*, const BT*, int ) const
    {
        return 0;
    }
};

struct HResizeNoVec
{
    template<typename T, typename WT, typename AT> inline
    int operator()(const T**, WT**, int, const int*,
        const AT*, int, int, int, int, int) const
    {
        return 0;
    }
};

#if CV_SIMD

struct VResizeLinearVec_32s8u
{
    int operator()(const int** src, uchar* dst, const short* beta, int width) const
    {
        const int *S0 = src[0], *S1 = src[1];
        int x = 0;
        v_int16 b0 = vx_setall_s16(beta[0]), b1 = vx_setall_s16(beta[1]);

        if( (((size_t)S0|(size_t)S1)&(CV_SIMD_WIDTH - 1)) == 0 )
            for( ; x <= width - v_uint8::nlanes; x += v_uint8::nlanes)
                v_store(dst + x, v_rshr_pack_u<2>(v_mul_hi(v_pack(vx_load_aligned(S0 + x                      ) >> 4, vx_load_aligned(S0 + x +     v_int32::nlanes) >> 4), b0) +
                                                  v_mul_hi(v_pack(vx_load_aligned(S1 + x                      ) >> 4, vx_load_aligned(S1 + x +     v_int32::nlanes) >> 4), b1),
                                                  v_mul_hi(v_pack(vx_load_aligned(S0 + x + 2 * v_int32::nlanes) >> 4, vx_load_aligned(S0 + x + 3 * v_int32::nlanes) >> 4), b0) +
                                                  v_mul_hi(v_pack(vx_load_aligned(S1 + x + 2 * v_int32::nlanes) >> 4, vx_load_aligned(S1 + x + 3 * v_int32::nlanes) >> 4), b1)));
        else
            for( ; x <= width - v_uint8::nlanes; x += v_uint8::nlanes)
                v_store(dst + x, v_rshr_pack_u<2>(v_mul_hi(v_pack(vx_load(S0 + x                      ) >> 4, vx_load(S0 + x +     v_int32::nlanes) >> 4), b0) +
                                                  v_mul_hi(v_pack(vx_load(S1 + x                      ) >> 4, vx_load(S1 + x +     v_int32::nlanes) >> 4), b1),
                                                  v_mul_hi(v_pack(vx_load(S0 + x + 2 * v_int32::nlanes) >> 4, vx_load(S0 + x + 3 * v_int32::nlanes) >> 4), b0) +
                                                  v_mul_hi(v_pack(vx_load(S1 + x + 2 * v_int32::nlanes) >> 4, vx_load(S1 + x + 3 * v_int32::nlanes) >> 4), b1)));

        for( ; x < width - v_int16::nlanes; x += v_int16::nlanes)
            v_rshr_pack_u_store<2>(dst + x, v_mul_hi(v_pack(vx_load(S0 + x) >> 4, vx_load(S0 + x + v_int32::nlanes) >> 4), b0) +
                                            v_mul_hi(v_pack(vx_load(S1 + x) >> 4, vx_load(S1 + x + v_int32::nlanes) >> 4), b1));

        return x;
    }
};

struct VResizeLinearVec_32f16u
{
    int operator()(const float** src, ushort* dst, const float* beta, int width) const
    {
        const float *S0 = src[0], *S1 = src[1];
        int x = 0;

        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]);

        if( (((size_t)S0|(size_t)S1)&(CV_SIMD_WIDTH - 1)) == 0 )
            for( ; x <= width - v_uint16::nlanes; x += v_uint16::nlanes)
                v_store(dst + x, v_pack_u(v_round(v_muladd(vx_load_aligned(S0 + x                    ), b0, vx_load_aligned(S1 + x                    ) * b1)),
                                          v_round(v_muladd(vx_load_aligned(S0 + x + v_float32::nlanes), b0, vx_load_aligned(S1 + x + v_float32::nlanes) * b1))));
        else
            for (; x <= width - v_uint16::nlanes; x += v_uint16::nlanes)
                v_store(dst + x, v_pack_u(v_round(v_muladd(vx_load(S0 + x                    ), b0, vx_load(S1 + x                    ) * b1)),
                                          v_round(v_muladd(vx_load(S0 + x + v_float32::nlanes), b0, vx_load(S1 + x + v_float32::nlanes) * b1))));
        for( ; x < width - v_float32::nlanes; x += v_float32::nlanes)
        {
            v_int32 t0 = v_round(v_muladd(vx_load(S0 + x), b0, vx_load(S1 + x) * b1));
            v_store_low(dst + x, v_pack_u(t0, t0));
        }

        return x;
    }
};

struct VResizeLinearVec_32f16s
{
    int operator()(const float** src, short* dst, const float* beta, int width) const
    {
        const float *S0 = src[0], *S1 = src[1];
        int x = 0;

        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]);

        if( (((size_t)S0|(size_t)S1)&(CV_SIMD_WIDTH - 1)) == 0 )
            for( ; x <= width - v_int16::nlanes; x += v_int16::nlanes)
                v_store(dst + x, v_pack(v_round(v_muladd(vx_load_aligned(S0 + x                    ), b0, vx_load_aligned(S1 + x                    ) * b1)),
                                        v_round(v_muladd(vx_load_aligned(S0 + x + v_float32::nlanes), b0, vx_load_aligned(S1 + x + v_float32::nlanes) * b1))));
        else
            for (; x <= width - v_int16::nlanes; x += v_int16::nlanes)
                v_store(dst + x, v_pack(v_round(v_muladd(vx_load(S0 + x                    ), b0, vx_load(S1 + x                    ) * b1)),
                                        v_round(v_muladd(vx_load(S0 + x + v_float32::nlanes), b0, vx_load(S1 + x + v_float32::nlanes) * b1))));
        for( ; x < width - v_float32::nlanes; x += v_float32::nlanes)
        {
            v_int32 t0 = v_round(v_muladd(vx_load(S0 + x), b0, vx_load(S1 + x) * b1));
            v_store_low(dst + x, v_pack(t0, t0));
        }

        return x;
    }
};

struct VResizeLinearVec_32f
{
    int operator()(const float** src, float* dst, const float* beta, int width) const
    {
        const float *S0 = src[0], *S1 = src[1];
        int x = 0;

        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]);

        if( (((size_t)S0|(size_t)S1)&(CV_SIMD_WIDTH - 1)) == 0 )
            for( ; x <= width - v_float32::nlanes; x += v_float32::nlanes)
                v_store(dst + x, v_muladd(vx_load_aligned(S0 + x), b0, vx_load_aligned(S1 + x) * b1));
        else
            for( ; x <= width - v_float32::nlanes; x += v_float32::nlanes)
                v_store(dst + x, v_muladd(vx_load(S0 + x), b0, vx_load(S1 + x) * b1));

        return x;
    }
};


struct VResizeCubicVec_32s8u
{
    int operator()(const int** src, uchar* dst, const short* beta, int width) const
    {
        const int *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        int x = 0;
        float scale = 1.f/(INTER_RESIZE_COEF_SCALE*INTER_RESIZE_COEF_SCALE);

        v_float32 b0 = vx_setall_f32(beta[0] * scale), b1 = vx_setall_f32(beta[1] * scale),
                  b2 = vx_setall_f32(beta[2] * scale), b3 = vx_setall_f32(beta[3] * scale);

        if( (((size_t)S0|(size_t)S1|(size_t)S2|(size_t)S3)&(CV_SIMD_WIDTH - 1)) == 0 )
            for( ; x <= width - v_int16::nlanes; x += v_int16::nlanes)
                v_pack_u_store(dst + x, v_pack(v_round(v_muladd(v_cvt_f32(vx_load_aligned(S0 + x                    )),  b0,
                                                       v_muladd(v_cvt_f32(vx_load_aligned(S1 + x                    )),  b1,
                                                       v_muladd(v_cvt_f32(vx_load_aligned(S2 + x                    )),  b2,
                                                                v_cvt_f32(vx_load_aligned(S3 + x                    )) * b3)))),
                                               v_round(v_muladd(v_cvt_f32(vx_load_aligned(S0 + x + v_float32::nlanes)),  b0,
                                                       v_muladd(v_cvt_f32(vx_load_aligned(S1 + x + v_float32::nlanes)),  b1,
                                                       v_muladd(v_cvt_f32(vx_load_aligned(S2 + x + v_float32::nlanes)),  b2,
                                                                v_cvt_f32(vx_load_aligned(S3 + x + v_float32::nlanes)) * b3))))));
        else
            for( ; x <= width - v_int16::nlanes; x += v_int16::nlanes)
                v_pack_u_store(dst + x, v_pack(v_round(v_muladd(v_cvt_f32(vx_load(S0 + x                    )),  b0,
                                                       v_muladd(v_cvt_f32(vx_load(S1 + x                    )),  b1,
                                                       v_muladd(v_cvt_f32(vx_load(S2 + x                    )),  b2,
                                                                v_cvt_f32(vx_load(S3 + x                    )) * b3)))),
                                               v_round(v_muladd(v_cvt_f32(vx_load(S0 + x + v_float32::nlanes)),  b0,
                                                       v_muladd(v_cvt_f32(vx_load(S1 + x + v_float32::nlanes)),  b1,
                                                       v_muladd(v_cvt_f32(vx_load(S2 + x + v_float32::nlanes)),  b2,
                                                                v_cvt_f32(vx_load(S3 + x + v_float32::nlanes)) * b3))))));
        return x;
    }
};

struct VResizeCubicVec_32f16u
{
    int operator()(const float** src, ushort* dst, const float* beta, int width) const
    {
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        int x = 0;
        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]),
                  b2 = vx_setall_f32(beta[2]), b3 = vx_setall_f32(beta[3]);

        for (; x <= width - v_uint16::nlanes; x += v_uint16::nlanes)
            v_store(dst + x, v_pack_u(v_round(v_muladd(vx_load(S0 + x                    ),  b0,
                                              v_muladd(vx_load(S1 + x                    ),  b1,
                                              v_muladd(vx_load(S2 + x                    ),  b2,
                                                       vx_load(S3 + x                    ) * b3)))),
                                      v_round(v_muladd(vx_load(S0 + x + v_float32::nlanes),  b0,
                                              v_muladd(vx_load(S1 + x + v_float32::nlanes),  b1,
                                              v_muladd(vx_load(S2 + x + v_float32::nlanes),  b2,
                                                       vx_load(S3 + x + v_float32::nlanes) * b3))))));

        return x;
    }
};

struct VResizeCubicVec_32f16s
{
    int operator()(const float** src, short* dst, const float* beta, int width) const
    {
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        int x = 0;
        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]),
                  b2 = vx_setall_f32(beta[2]), b3 = vx_setall_f32(beta[3]);

        for (; x <= width - v_int16::nlanes; x += v_int16::nlanes)
            v_store(dst + x, v_pack(v_round(v_muladd(vx_load(S0 + x                    ),  b0,
                                            v_muladd(vx_load(S1 + x                    ),  b1,
                                            v_muladd(vx_load(S2 + x                    ),  b2,
                                                     vx_load(S3 + x                    ) * b3)))),
                                    v_round(v_muladd(vx_load(S0 + x + v_float32::nlanes),  b0,
                                            v_muladd(vx_load(S1 + x + v_float32::nlanes),  b1,
                                            v_muladd(vx_load(S2 + x + v_float32::nlanes),  b2,
                                                     vx_load(S3 + x + v_float32::nlanes) * b3))))));

        return x;
    }
};

struct VResizeCubicVec_32f
{
    int operator()(const float** src, float* dst, const float* beta, int width) const
    {
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        int x = 0;
        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]),
                  b2 = vx_setall_f32(beta[2]), b3 = vx_setall_f32(beta[3]);

        for( ; x <= width - v_float32::nlanes; x += v_float32::nlanes)
            v_store(dst + x, v_muladd(vx_load(S0 + x),  b0,
                             v_muladd(vx_load(S1 + x),  b1,
                             v_muladd(vx_load(S2 + x),  b2,
                                      vx_load(S3 + x) * b3))));

        return x;
    }
};


#if CV_TRY_SSE4_1

struct VResizeLanczos4Vec_32f16u
{
    int operator()(const float** src, ushort* dst, const float* beta, int width) const
    {
        if (CV_CPU_HAS_SUPPORT_SSE4_1)
            return opt_SSE4_1::VResizeLanczos4Vec_32f16u_SSE41(src, dst, beta, width);
        else
            return 0;
    }
};

#else

struct VResizeLanczos4Vec_32f16u
{
    int operator()(const float** src, ushort* dst, const float* beta, int width ) const
    {
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        int x = 0;
        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]),
                  b2 = vx_setall_f32(beta[2]), b3 = vx_setall_f32(beta[3]),
                  b4 = vx_setall_f32(beta[4]), b5 = vx_setall_f32(beta[5]),
                  b6 = vx_setall_f32(beta[6]), b7 = vx_setall_f32(beta[7]);

        for( ; x <= width - v_uint16::nlanes; x += v_uint16::nlanes)
            v_store(dst + x, v_pack_u(v_round(v_muladd(vx_load(S0 + x                    ),  b0,
                                              v_muladd(vx_load(S1 + x                    ),  b1,
                                              v_muladd(vx_load(S2 + x                    ),  b2,
                                              v_muladd(vx_load(S3 + x                    ),  b3,
                                              v_muladd(vx_load(S4 + x                    ),  b4,
                                              v_muladd(vx_load(S5 + x                    ),  b5,
                                              v_muladd(vx_load(S6 + x                    ),  b6,
                                                       vx_load(S7 + x                    ) * b7)))))))),
                                      v_round(v_muladd(vx_load(S0 + x + v_float32::nlanes),  b0,
                                              v_muladd(vx_load(S1 + x + v_float32::nlanes),  b1,
                                              v_muladd(vx_load(S2 + x + v_float32::nlanes),  b2,
                                              v_muladd(vx_load(S3 + x + v_float32::nlanes),  b3,
                                              v_muladd(vx_load(S4 + x + v_float32::nlanes),  b4,
                                              v_muladd(vx_load(S5 + x + v_float32::nlanes),  b5,
                                              v_muladd(vx_load(S6 + x + v_float32::nlanes),  b6,
                                                       vx_load(S7 + x + v_float32::nlanes) * b7))))))))));

        return x;
    }
};

#endif

struct VResizeLanczos4Vec_32f16s
{
    int operator()(const float** src, short* dst, const float* beta, int width ) const
    {
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        int x = 0;
        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]),
                  b2 = vx_setall_f32(beta[2]), b3 = vx_setall_f32(beta[3]),
                  b4 = vx_setall_f32(beta[4]), b5 = vx_setall_f32(beta[5]),
                  b6 = vx_setall_f32(beta[6]), b7 = vx_setall_f32(beta[7]);

        for( ; x <= width - v_int16::nlanes; x += v_int16::nlanes)
            v_store(dst + x, v_pack(v_round(v_muladd(vx_load(S0 + x                    ),  b0,
                                            v_muladd(vx_load(S1 + x                    ),  b1,
                                            v_muladd(vx_load(S2 + x                    ),  b2,
                                            v_muladd(vx_load(S3 + x                    ),  b3,
                                            v_muladd(vx_load(S4 + x                    ),  b4,
                                            v_muladd(vx_load(S5 + x                    ),  b5,
                                            v_muladd(vx_load(S6 + x                    ),  b6,
                                                     vx_load(S7 + x                    ) * b7)))))))),
                                    v_round(v_muladd(vx_load(S0 + x + v_float32::nlanes),  b0,
                                            v_muladd(vx_load(S1 + x + v_float32::nlanes),  b1,
                                            v_muladd(vx_load(S2 + x + v_float32::nlanes),  b2,
                                            v_muladd(vx_load(S3 + x + v_float32::nlanes),  b3,
                                            v_muladd(vx_load(S4 + x + v_float32::nlanes),  b4,
                                            v_muladd(vx_load(S5 + x + v_float32::nlanes),  b5,
                                            v_muladd(vx_load(S6 + x + v_float32::nlanes),  b6,
                                                     vx_load(S7 + x + v_float32::nlanes) * b7))))))))));

        return x;
    }
};

struct VResizeLanczos4Vec_32f
{
    int operator()(const float** src, float* dst, const float* beta, int width ) const
    {
        const float *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3],
                    *S4 = src[4], *S5 = src[5], *S6 = src[6], *S7 = src[7];
        int x = 0;

        v_float32 b0 = vx_setall_f32(beta[0]), b1 = vx_setall_f32(beta[1]),
                  b2 = vx_setall_f32(beta[2]), b3 = vx_setall_f32(beta[3]),
                  b4 = vx_setall_f32(beta[4]), b5 = vx_setall_f32(beta[5]),
                  b6 = vx_setall_f32(beta[6]), b7 = vx_setall_f32(beta[7]);

        for( ; x <= width - v_float32::nlanes; x += v_float32::nlanes)
            v_store(dst + x, v_muladd(vx_load(S0 + x),  b0,
                             v_muladd(vx_load(S1 + x),  b1,
                             v_muladd(vx_load(S2 + x),  b2,
                             v_muladd(vx_load(S3 + x),  b3,
                             v_muladd(vx_load(S4 + x),  b4,
                             v_muladd(vx_load(S5 + x),  b5,
                             v_muladd(vx_load(S6 + x),  b6,
                                      vx_load(S7 + x) * b7))))))));

        return x;
    }
};

#else

typedef VResizeNoVec VResizeLinearVec_32s8u;
typedef VResizeNoVec VResizeLinearVec_32f16u;
typedef VResizeNoVec VResizeLinearVec_32f16s;
typedef VResizeNoVec VResizeLinearVec_32f;

typedef VResizeNoVec VResizeCubicVec_32s8u;
typedef VResizeNoVec VResizeCubicVec_32f16u;
typedef VResizeNoVec VResizeCubicVec_32f16s;
typedef VResizeNoVec VResizeCubicVec_32f;

typedef VResizeNoVec VResizeLanczos4Vec_32f16u;
typedef VResizeNoVec VResizeLanczos4Vec_32f16s;
typedef VResizeNoVec VResizeLanczos4Vec_32f;

#endif

#if CV_SIMD128

template<typename ST, typename DT, typename AT, typename DVT>
struct HResizeLinearVec_X4
{
    int operator()(const ST** src, DT** dst, int count, const int* xofs,
        const AT* alpha, int, int, int cn, int, int xmax) const
    {
        const int nlanes = 4;
        const int len0 = xmax & -nlanes;
        int dx = 0, k = 0;

        for( ; k <= (count - 2); k+=2 )
        {
            const ST *S0 = src[k];
            DT *D0 = dst[k];
            const ST *S1 = src[k+1];
            DT *D1 = dst[k+1];

            for( dx = 0; dx < len0; dx += nlanes )
            {
                int sx0 = xofs[dx+0];
                int sx1 = xofs[dx+1];
                int sx2 = xofs[dx+2];
                int sx3 = xofs[dx+3];
                DVT a_even;
                DVT a_odd;

                v_load_deinterleave(&alpha[dx*2], a_even, a_odd);
                DVT s0(S0[sx0], S0[sx1], S0[sx2], S0[sx3]);
                DVT s1(S0[sx0+cn], S0[sx1+cn], S0[sx2+cn], S0[sx3+cn]);
                DVT s0_u(S1[sx0], S1[sx1], S1[sx2], S1[sx3]);
                DVT s1_u(S1[sx0+cn], S1[sx1+cn], S1[sx2+cn], S1[sx3+cn]);
                v_store(&D1[dx], s0_u * a_even + s1_u * a_odd);
                v_store(&D0[dx], s0 * a_even + s1 * a_odd);
            }
        }
        for( ; k < count; k++ )
        {
            const ST *S = src[k];
            DT *D = dst[k];
            for( dx = 0; dx < len0; dx += nlanes )
            {
                int sx0 = xofs[dx+0];
                int sx1 = xofs[dx+1];
                int sx2 = xofs[dx+2];
                int sx3 = xofs[dx+3];
                DVT a_even;
                DVT a_odd;

                v_load_deinterleave(&alpha[dx*2], a_even, a_odd);
                DVT s0(S[sx0], S[sx1], S[sx2], S[sx3]);
                DVT s1(S[sx0+cn], S[sx1+cn], S[sx2+cn], S[sx3+cn]);
                v_store(&D[dx], s0 * a_even + s1 * a_odd);
            }
        }
        return dx;
    }
};

struct HResizeLinearVecU8_X4
{
    int operator()(const uchar** src, int** dst, int count, const int* xofs,
        const short* alpha/*[xmax]*/, int /*smax*/, int dmax, int cn, int /*xmin*/, int xmax) const
    {
        int dx = 0, k = 0;

        if(cn == 1)
        {
            const int step = 8;
            const int len0 = xmax & -step;
            for( ; k <= (count - 2); k+=2 )
            {
                const uchar *S0 = src[k];
                int *D0 = dst[k];
                const uchar *S1 = src[k+1];
                int *D1 = dst[k+1];

                for( dx = 0; dx < len0; dx += step )
                {
                    v_int16x8 al = v_load(alpha+dx*2);
                    v_int16x8 ah = v_load(alpha+dx*2+8);
                    v_uint16x8 sl, sh;
                    v_expand(v_lut_pairs(S0, xofs+dx), sl, sh);
                    v_store(&D0[dx], v_dotprod(v_reinterpret_as_s16(sl), al));
                    v_store(&D0[dx+4], v_dotprod(v_reinterpret_as_s16(sh), ah));
                    v_expand(v_lut_pairs(S1, xofs+dx), sl, sh);
                    v_store(&D1[dx], v_dotprod(v_reinterpret_as_s16(sl), al));
                    v_store(&D1[dx+4], v_dotprod(v_reinterpret_as_s16(sh), ah));
                }
            }
            for( ; k < count; k++ )
            {
                const uchar *S = src[k];
                int *D = dst[k];
                for( dx = 0; dx < len0; dx += step )
                {
                    v_int16x8 al = v_load(alpha+dx*2);
                    v_int16x8 ah = v_load(alpha+dx*2+8);
                    v_uint16x8 sl, sh;
                    v_expand(v_lut_pairs(S, xofs+dx), sl, sh);
                    v_store(&D[dx], v_dotprod(v_reinterpret_as_s16(sl), al));
                    v_store(&D[dx+4], v_dotprod(v_reinterpret_as_s16(sh), ah));
                }
            }
        }
        else if(cn == 2)
        {
            const int step = 8;
            const int len0 = xmax & -step;
            for( ; k <= (count - 2); k+=2 )
            {
                const uchar *S0 = src[k];
                int *D0 = dst[k];
                const uchar *S1 = src[k+1];
                int *D1 = dst[k+1];

                for( dx = 0; dx < len0; dx += step )
                {
                    int ofs[4] = { xofs[dx], xofs[dx + 2], xofs[dx + 4], xofs[dx + 6] };
                    v_int16x8 al = v_load(alpha+dx*2);
                    v_int16x8 ah = v_load(alpha+dx*2+8);
                    v_uint16x8 sl, sh;
                    v_expand(v_interleave_pairs(v_lut_quads(S0, ofs)), sl, sh);
                    v_store(&D0[dx], v_dotprod(v_reinterpret_as_s16(sl), al));
                    v_store(&D0[dx+4], v_dotprod(v_reinterpret_as_s16(sh), ah));
                    v_expand(v_interleave_pairs(v_lut_quads(S1, ofs)), sl, sh);
                    v_store(&D1[dx], v_dotprod(v_reinterpret_as_s16(sl), al));
                    v_store(&D1[dx+4], v_dotprod(v_reinterpret_as_s16(sh), ah));
                }
            }
            for( ; k < count; k++ )
            {
                const uchar *S = src[k];
                int *D = dst[k];
                for( dx = 0; dx < len0; dx += step )
                {
                    int ofs[4] = { xofs[dx], xofs[dx + 2], xofs[dx + 4], xofs[dx + 6] };
                    v_int16x8 al = v_load(alpha+dx*2);
                    v_int16x8 ah = v_load(alpha+dx*2+8);
                    v_uint16x8 sl, sh;
                    v_expand(v_interleave_pairs(v_lut_quads(S, ofs)), sl, sh);
                    v_store(&D[dx], v_dotprod(v_reinterpret_as_s16(sl), al));
                    v_store(&D[dx+4], v_dotprod(v_reinterpret_as_s16(sh), ah));
                }
            }
        }
        else if(cn == 3)
        {
            /* Peek at the last x offset to find the maximal s offset.  We know the loop
               will terminate prior to value which may be 1 or more elements prior to the
               final valid offset. xofs[] is constucted to be an array of increasingly
               large offsets (i.e xofs[x] <= xofs[x+1] for x < xmax). */
            int smax = xofs[dmax-cn];

            for( ; k <= (count - 2); k+=2 )
            {
                const uchar *S0 = src[k];
                int *D0 = dst[k];
                const uchar *S1 = src[k+1];
                int *D1 = dst[k+1];

                for( dx = 0; (xofs[dx] + cn) < smax; dx += cn )
                {
                    v_int16x8 a = v_load(alpha+dx*2);
                    v_store(&D0[dx], v_dotprod(v_reinterpret_as_s16(v_load_expand_q(S0+xofs[dx]) | (v_load_expand_q(S0+xofs[dx]+cn)<<16)), a));
                    v_store(&D1[dx], v_dotprod(v_reinterpret_as_s16(v_load_expand_q(S1+xofs[dx]) | (v_load_expand_q(S1+xofs[dx]+cn)<<16)), a));
                }
            }
            for( ; k < count; k++ )
            {
                const uchar *S = src[k];
                int *D = dst[k];
                for( dx = 0; (xofs[dx] + cn) < smax; dx += cn )
                {
                    v_int16x8 a = v_load(alpha+dx*2);
                    v_store(&D[dx], v_dotprod(v_reinterpret_as_s16(v_load_expand_q(S+xofs[dx]) | (v_load_expand_q(S+xofs[dx]+cn)<<16)), a));
                }
            }
            /* Debug check to ensure truthiness that we never vector the final value. */
            CV_DbgAssert(dx < dmax);
        }
        else if(cn == 4)
        {
            const int step = 4;
            const int len0 = xmax & -step;
            for( ; k <= (count - 2); k+=2 )
            {
                const uchar *S0 = src[k];
                int *D0 = dst[k];
                const uchar *S1 = src[k+1];
                int *D1 = dst[k+1];

                for( dx = 0; dx < len0; dx += step )
                {
                    v_int16x8 a = v_load(alpha+dx*2);
                    v_store(&D0[dx], v_dotprod(v_reinterpret_as_s16(v_interleave_quads(v_load_expand(S0+xofs[dx]))), a));
                    v_store(&D1[dx], v_dotprod(v_reinterpret_as_s16(v_interleave_quads(v_load_expand(S1+xofs[dx]))), a));
                }
            }
            for( ; k < count; k++ )
            {
                const uchar *S = src[k];
                int *D = dst[k];
                for( dx = 0; dx < len0; dx += step )
                {
                    v_int16x8 a = v_load(alpha+dx*2);
                    v_store(&D[dx], v_dotprod(v_reinterpret_as_s16(v_interleave_quads(v_load_expand(S+xofs[dx]))), a));
                }
            }
        }
        else
        {
            return 0;  // images with channels >4 are out of optimization scope
        }
        return dx;
    }
};

typedef HResizeLinearVec_X4<float,float,float,v_float32x4> HResizeLinearVec_32f;
typedef HResizeLinearVec_X4<ushort,float,float,v_float32x4> HResizeLinearVec_16u32f;
typedef HResizeLinearVec_X4<short,float,float,v_float32x4> HResizeLinearVec_16s32f;
typedef HResizeLinearVecU8_X4 HResizeLinearVec_8u32s;

#else

typedef HResizeNoVec HResizeLinearVec_8u32s;
typedef HResizeNoVec HResizeLinearVec_16u32f;
typedef HResizeNoVec HResizeLinearVec_16s32f;
typedef HResizeNoVec HResizeLinearVec_32f;

#endif

typedef HResizeNoVec HResizeLinearVec_64f;


template<typename T, typename WT, typename AT, int ONE, class VecOp>
struct HResizeLinear
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const T** src, WT** dst, int count,
                    const int* xofs, const AT* alpha,
                    int swidth, int dwidth, int cn, int xmin, int xmax ) const
    {
        int dx, k;
        VecOp vecOp;

        int dx0 = vecOp(src, dst, count,
            xofs, alpha, swidth, dwidth, cn, xmin, xmax );

        for( k = 0; k <= count - 2; k+=2 )
        {
            const T *S0 = src[k], *S1 = src[k+1];
            WT *D0 = dst[k], *D1 = dst[k+1];
            for( dx = dx0; dx < xmax; dx++ )
            {
                int sx = xofs[dx];
                WT a0 = alpha[dx*2], a1 = alpha[dx*2+1];
                WT t0 = S0[sx]*a0 + S0[sx + cn]*a1;
                WT t1 = S1[sx]*a0 + S1[sx + cn]*a1;
                D0[dx] = t0; D1[dx] = t1;
            }

            for( ; dx < dwidth; dx++ )
            {
                int sx = xofs[dx];
                D0[dx] = WT(S0[sx]*ONE); D1[dx] = WT(S1[sx]*ONE);
            }
        }

        for( ; k < count; k++ )
        {
            const T *S = src[k];
            WT *D = dst[k];
            for( dx = dx0; dx < xmax; dx++ )
            {
                int sx = xofs[dx];
                D[dx] = S[sx]*alpha[dx*2] + S[sx+cn]*alpha[dx*2+1];
            }

            for( ; dx < dwidth; dx++ )
                D[dx] = WT(S[xofs[dx]]*ONE);
        }
    }
};


template<typename T, typename WT, typename AT, class CastOp, class VecOp>
struct VResizeLinear
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const WT** src, T* dst, const AT* beta, int width ) const
    {
        WT b0 = beta[0], b1 = beta[1];
        const WT *S0 = src[0], *S1 = src[1];
        CastOp castOp;
        VecOp vecOp;

        int x = vecOp(src, dst, beta, width);
        #if CV_ENABLE_UNROLLED
        for( ; x <= width - 4; x += 4 )
        {
            WT t0, t1;
            t0 = S0[x]*b0 + S1[x]*b1;
            t1 = S0[x+1]*b0 + S1[x+1]*b1;
            dst[x] = castOp(t0); dst[x+1] = castOp(t1);
            t0 = S0[x+2]*b0 + S1[x+2]*b1;
            t1 = S0[x+3]*b0 + S1[x+3]*b1;
            dst[x+2] = castOp(t0); dst[x+3] = castOp(t1);
        }
        #endif
        for( ; x < width; x++ )
            dst[x] = castOp(S0[x]*b0 + S1[x]*b1);
    }
};

template<>
struct VResizeLinear<uchar, int, short, FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>, VResizeLinearVec_32s8u>
{
    typedef uchar value_type;
    typedef int buf_type;
    typedef short alpha_type;

    void operator()(const buf_type** src, value_type* dst, const alpha_type* beta, int width ) const
    {
        alpha_type b0 = beta[0], b1 = beta[1];
        const buf_type *S0 = src[0], *S1 = src[1];
        VResizeLinearVec_32s8u vecOp;

        int x = vecOp(src, dst, beta, width);
        #if CV_ENABLE_UNROLLED
        for( ; x <= width - 4; x += 4 )
        {
            dst[x+0] = uchar(( ((b0 * (S0[x+0] >> 4)) >> 16) + ((b1 * (S1[x+0] >> 4)) >> 16) + 2)>>2);
            dst[x+1] = uchar(( ((b0 * (S0[x+1] >> 4)) >> 16) + ((b1 * (S1[x+1] >> 4)) >> 16) + 2)>>2);
            dst[x+2] = uchar(( ((b0 * (S0[x+2] >> 4)) >> 16) + ((b1 * (S1[x+2] >> 4)) >> 16) + 2)>>2);
            dst[x+3] = uchar(( ((b0 * (S0[x+3] >> 4)) >> 16) + ((b1 * (S1[x+3] >> 4)) >> 16) + 2)>>2);
        }
        #endif
        for( ; x < width; x++ )
            dst[x] = uchar(( ((b0 * (S0[x] >> 4)) >> 16) + ((b1 * (S1[x] >> 4)) >> 16) + 2)>>2);
    }
};


template<typename T, typename WT, typename AT>
struct HResizeCubic
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const T** src, WT** dst, int count,
                    const int* xofs, const AT* alpha,
                    int swidth, int dwidth, int cn, int xmin, int xmax ) const
    {
        for( int k = 0; k < count; k++ )
        {
            const T *S = src[k];
            WT *D = dst[k];
            int dx = 0, limit = xmin;
            for(;;)
            {
                for( ; dx < limit; dx++, alpha += 4 )
                {
                    int j, sx = xofs[dx] - cn;
                    WT v = 0;
                    for( j = 0; j < 4; j++ )
                    {
                        int sxj = sx + j*cn;
                        if( (unsigned)sxj >= (unsigned)swidth )
                        {
                            while( sxj < 0 )
                                sxj += cn;
                            while( sxj >= swidth )
                                sxj -= cn;
                        }
                        v += S[sxj]*alpha[j];
                    }
                    D[dx] = v;
                }
                if( limit == dwidth )
                    break;
                for( ; dx < xmax; dx++, alpha += 4 )
                {
                    int sx = xofs[dx];
                    D[dx] = S[sx-cn]*alpha[0] + S[sx]*alpha[1] +
                        S[sx+cn]*alpha[2] + S[sx+cn*2]*alpha[3];
                }
                limit = dwidth;
            }
            alpha -= dwidth*4;
        }
    }
};


template<typename T, typename WT, typename AT, class CastOp, class VecOp>
struct VResizeCubic
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const WT** src, T* dst, const AT* beta, int width ) const
    {
        WT b0 = beta[0], b1 = beta[1], b2 = beta[2], b3 = beta[3];
        const WT *S0 = src[0], *S1 = src[1], *S2 = src[2], *S3 = src[3];
        CastOp castOp;
        VecOp vecOp;

        int x = vecOp(src, dst, beta, width);
        for( ; x < width; x++ )
            dst[x] = castOp(S0[x]*b0 + S1[x]*b1 + S2[x]*b2 + S3[x]*b3);
    }
};


template<typename T, typename WT, typename AT>
struct HResizeLanczos4
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const T** src, WT** dst, int count,
                    const int* xofs, const AT* alpha,
                    int swidth, int dwidth, int cn, int xmin, int xmax ) const
    {
        for( int k = 0; k < count; k++ )
        {
            const T *S = src[k];
            WT *D = dst[k];
            int dx = 0, limit = xmin;
            for(;;)
            {
                for( ; dx < limit; dx++, alpha += 8 )
                {
                    int j, sx = xofs[dx] - cn*3;
                    WT v = 0;
                    for( j = 0; j < 8; j++ )
                    {
                        int sxj = sx + j*cn;
                        if( (unsigned)sxj >= (unsigned)swidth )
                        {
                            while( sxj < 0 )
                                sxj += cn;
                            while( sxj >= swidth )
                                sxj -= cn;
                        }
                        v += S[sxj]*alpha[j];
                    }
                    D[dx] = v;
                }
                if( limit == dwidth )
                    break;
                for( ; dx < xmax; dx++, alpha += 8 )
                {
                    int sx = xofs[dx];
                    D[dx] = S[sx-cn*3]*alpha[0] + S[sx-cn*2]*alpha[1] +
                        S[sx-cn]*alpha[2] + S[sx]*alpha[3] +
                        S[sx+cn]*alpha[4] + S[sx+cn*2]*alpha[5] +
                        S[sx+cn*3]*alpha[6] + S[sx+cn*4]*alpha[7];
                }
                limit = dwidth;
            }
            alpha -= dwidth*8;
        }
    }
};


template<typename T, typename WT, typename AT, class CastOp, class VecOp>
struct VResizeLanczos4
{
    typedef T value_type;
    typedef WT buf_type;
    typedef AT alpha_type;

    void operator()(const WT** src, T* dst, const AT* beta, int width ) const
    {
        CastOp castOp;
        VecOp vecOp;
        int x = vecOp(src, dst, beta, width);
        #if CV_ENABLE_UNROLLED
        for( ; x <= width - 4; x += 4 )
        {
            WT b = beta[0];
            const WT* S = src[0];
            WT s0 = S[x]*b, s1 = S[x+1]*b, s2 = S[x+2]*b, s3 = S[x+3]*b;

            for( int k = 1; k < 8; k++ )
            {
                b = beta[k]; S = src[k];
                s0 += S[x]*b; s1 += S[x+1]*b;
                s2 += S[x+2]*b; s3 += S[x+3]*b;
            }

            dst[x] = castOp(s0); dst[x+1] = castOp(s1);
            dst[x+2] = castOp(s2); dst[x+3] = castOp(s3);
        }
        #endif
        for( ; x < width; x++ )
        {
            dst[x] = castOp(src[0][x]*beta[0] + src[1][x]*beta[1] +
                src[2][x]*beta[2] + src[3][x]*beta[3] + src[4][x]*beta[4] +
                src[5][x]*beta[5] + src[6][x]*beta[6] + src[7][x]*beta[7]);
        }
    }
};


static inline int clip(int x, int a, int b)
{
    return x >= a ? (x < b ? x : b-1) : a;
}

static const int MAX_ESIZE=16;

template <typename HResize, typename VResize>
class resizeGeneric_Invoker :
    public ParallelLoopBody
{
public:
    typedef typename HResize::value_type T;
    typedef typename HResize::buf_type WT;
    typedef typename HResize::alpha_type AT;

    resizeGeneric_Invoker(const Mat& _src, Mat &_dst, const int *_xofs, const int *_yofs,
        const AT* _alpha, const AT* __beta, const Size& _ssize, const Size &_dsize,
        int _ksize, int _xmin, int _xmax) :
        ParallelLoopBody(), src(_src), dst(_dst), xofs(_xofs), yofs(_yofs),
        alpha(_alpha), _beta(__beta), ssize(_ssize), dsize(_dsize),
        ksize(_ksize), xmin(_xmin), xmax(_xmax)
    {
        CV_Assert(ksize <= MAX_ESIZE);
    }

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        int dy, cn = src.channels();
        HResize hresize;
        VResize vresize;

        int bufstep = (int)alignSize(dsize.width, 16);
        AutoBuffer<WT> _buffer(bufstep*ksize);
        const T* srows[MAX_ESIZE]={0};
        WT* rows[MAX_ESIZE]={0};
        int prev_sy[MAX_ESIZE];

        for(int k = 0; k < ksize; k++ )
        {
            prev_sy[k] = -1;
            rows[k] = _buffer.data() + bufstep*k;
        }

        const AT* beta = _beta + ksize * range.start;

        for( dy = range.start; dy < range.end; dy++, beta += ksize )
        {
            int sy0 = yofs[dy], k0=ksize, k1=0, ksize2 = ksize/2;

            for(int k = 0; k < ksize; k++ )
            {
                int sy = clip(sy0 - ksize2 + 1 + k, 0, ssize.height);
                for( k1 = std::max(k1, k); k1 < ksize; k1++ )
                {
                    if( k1 < MAX_ESIZE && sy == prev_sy[k1] ) // if the sy-th row has been computed already, reuse it.
                    {
                        if( k1 > k )
                            memcpy( rows[k], rows[k1], bufstep*sizeof(rows[0][0]) );
                        break;
                    }
                }
                if( k1 == ksize )
                    k0 = std::min(k0, k); // remember the first row that needs to be computed
                srows[k] = src.template ptr<T>(sy);
                prev_sy[k] = sy;
            }

            if( k0 < ksize )
                hresize( (const T**)(srows + k0), (WT**)(rows + k0), ksize - k0, xofs, (const AT*)(alpha),
                        ssize.width, dsize.width, cn, xmin, xmax );
            vresize( (const WT**)rows, (T*)(dst.data + dst.step*dy), beta, dsize.width );
        }
    }

private:
    Mat src;
    Mat dst;
    const int* xofs, *yofs;
    const AT* alpha, *_beta;
    Size ssize, dsize;
    const int ksize, xmin, xmax;

    resizeGeneric_Invoker& operator = (const resizeGeneric_Invoker&);
};

template<class HResize, class VResize>
static void resizeGeneric_( const Mat& src, Mat& dst,
                            const int* xofs, const void* _alpha,
                            const int* yofs, const void* _beta,
                            int xmin, int xmax, int ksize )
{
    typedef typename HResize::alpha_type AT;

    const AT* beta = (const AT*)_beta;
    Size ssize = src.size(), dsize = dst.size();
    int cn = src.channels();
    ssize.width *= cn;
    dsize.width *= cn;
    xmin *= cn;
    xmax *= cn;
    // image resize is a separable operation. In case of not too strong

    Range range(0, dsize.height);
    resizeGeneric_Invoker<HResize, VResize> invoker(src, dst, xofs, yofs, (const AT*)_alpha, beta,
        ssize, dsize, ksize, xmin, xmax);
    parallel_for_(range, invoker, dst.total()/(double)(1<<16));
}

template <typename T, typename WT>
struct ResizeAreaFastNoVec
{
    ResizeAreaFastNoVec(int, int) { }
    ResizeAreaFastNoVec(int, int, int, int) { }
    int operator() (const T*, T*, int) const
    { return 0; }
};

#if CV_NEON

class ResizeAreaFastVec_SIMD_8u
{
public:
    ResizeAreaFastVec_SIMD_8u(int _cn, int _step) :
        cn(_cn), step(_step)
    {
    }

    int operator() (const uchar* S, uchar* D, int w) const
    {
        int dx = 0;
        const uchar* S0 = S, * S1 = S0 + step;

        uint16x8_t v_2 = vdupq_n_u16(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 16; dx += 16, S0 += 32, S1 += 32, D += 16)
            {
                uint8x16x2_t v_row0 = vld2q_u8(S0), v_row1 = vld2q_u8(S1);

                uint16x8_t v_dst0 = vaddl_u8(vget_low_u8(v_row0.val[0]), vget_low_u8(v_row0.val[1]));
                v_dst0 = vaddq_u16(v_dst0, vaddl_u8(vget_low_u8(v_row1.val[0]), vget_low_u8(v_row1.val[1])));
                v_dst0 = vshrq_n_u16(vaddq_u16(v_dst0, v_2), 2);

                uint16x8_t v_dst1 = vaddl_u8(vget_high_u8(v_row0.val[0]), vget_high_u8(v_row0.val[1]));
                v_dst1 = vaddq_u16(v_dst1, vaddl_u8(vget_high_u8(v_row1.val[0]), vget_high_u8(v_row1.val[1])));
                v_dst1 = vshrq_n_u16(vaddq_u16(v_dst1, v_2), 2);

                vst1q_u8(D, vcombine_u8(vmovn_u16(v_dst0), vmovn_u16(v_dst1)));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                uint8x16_t v_row0 = vld1q_u8(S0), v_row1 = vld1q_u8(S1);

                uint16x8_t v_row00 = vmovl_u8(vget_low_u8(v_row0));
                uint16x8_t v_row01 = vmovl_u8(vget_high_u8(v_row0));
                uint16x8_t v_row10 = vmovl_u8(vget_low_u8(v_row1));
                uint16x8_t v_row11 = vmovl_u8(vget_high_u8(v_row1));

                uint16x4_t v_p0 = vadd_u16(vadd_u16(vget_low_u16(v_row00), vget_high_u16(v_row00)),
                                           vadd_u16(vget_low_u16(v_row10), vget_high_u16(v_row10)));
                uint16x4_t v_p1 = vadd_u16(vadd_u16(vget_low_u16(v_row01), vget_high_u16(v_row01)),
                                           vadd_u16(vget_low_u16(v_row11), vget_high_u16(v_row11)));
                uint16x8_t v_dst = vshrq_n_u16(vaddq_u16(vcombine_u16(v_p0, v_p1), v_2), 2);

                vst1_u8(D, vmovn_u16(v_dst));
            }
        }

        return dx;
    }

private:
    int cn, step;
};

class ResizeAreaFastVec_SIMD_16u
{
public:
    ResizeAreaFastVec_SIMD_16u(int _cn, int _step) :
        cn(_cn), step(_step)
    {
    }

    int operator() (const ushort * S, ushort * D, int w) const
    {
        int dx = 0;
        const ushort * S0 = S, * S1 = (const ushort *)((const uchar *)(S0) + step);

        uint32x4_t v_2 = vdupq_n_u32(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                uint16x8x2_t v_row0 = vld2q_u16(S0), v_row1 = vld2q_u16(S1);

                uint32x4_t v_dst0 = vaddl_u16(vget_low_u16(v_row0.val[0]), vget_low_u16(v_row0.val[1]));
                v_dst0 = vaddq_u32(v_dst0, vaddl_u16(vget_low_u16(v_row1.val[0]), vget_low_u16(v_row1.val[1])));
                v_dst0 = vshrq_n_u32(vaddq_u32(v_dst0, v_2), 2);

                uint32x4_t v_dst1 = vaddl_u16(vget_high_u16(v_row0.val[0]), vget_high_u16(v_row0.val[1]));
                v_dst1 = vaddq_u32(v_dst1, vaddl_u16(vget_high_u16(v_row1.val[0]), vget_high_u16(v_row1.val[1])));
                v_dst1 = vshrq_n_u32(vaddq_u32(v_dst1, v_2), 2);

                vst1q_u16(D, vcombine_u16(vmovn_u32(v_dst0), vmovn_u32(v_dst1)));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                uint16x8_t v_row0 = vld1q_u16(S0), v_row1 = vld1q_u16(S1);
                uint32x4_t v_dst = vaddq_u32(vaddl_u16(vget_low_u16(v_row0), vget_high_u16(v_row0)),
                                             vaddl_u16(vget_low_u16(v_row1), vget_high_u16(v_row1)));
                vst1_u16(D, vmovn_u32(vshrq_n_u32(vaddq_u32(v_dst, v_2), 2)));
            }
        }

        return dx;
    }

private:
    int cn, step;
};

class ResizeAreaFastVec_SIMD_16s
{
public:
    ResizeAreaFastVec_SIMD_16s(int _cn, int _step) :
        cn(_cn), step(_step)
    {
    }

    int operator() (const short * S, short * D, int w) const
    {
        int dx = 0;
        const short * S0 = S, * S1 = (const short *)((const uchar *)(S0) + step);

        int32x4_t v_2 = vdupq_n_s32(2);

        if (cn == 1)
        {
            for ( ; dx <= w - 8; dx += 8, S0 += 16, S1 += 16, D += 8)
            {
                int16x8x2_t v_row0 = vld2q_s16(S0), v_row1 = vld2q_s16(S1);

                int32x4_t v_dst0 = vaddl_s16(vget_low_s16(v_row0.val[0]), vget_low_s16(v_row0.val[1]));
                v_dst0 = vaddq_s32(v_dst0, vaddl_s16(vget_low_s16(v_row1.val[0]), vget_low_s16(v_row1.val[1])));
                v_dst0 = vshrq_n_s32(vaddq_s32(v_dst0, v_2), 2);

                int32x4_t v_dst1 = vaddl_s16(vget_high_s16(v_row0.val[0]), vget_high_s16(v_row0.val[1]));
                v_dst1 = vaddq_s32(v_dst1, vaddl_s16(vget_high_s16(v_row1.val[0]), vget_high_s16(v_row1.val[1])));
                v_dst1 = vshrq_n_s32(vaddq_s32(v_dst1, v_2), 2);

                vst1q_s16(D, vcombine_s16(vmovn_s32(v_dst0), vmovn_s32(v_dst1)));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                int16x8_t v_row0 = vld1q_s16(S0), v_row1 = vld1q_s16(S1);
                int32x4_t v_dst = vaddq_s32(vaddl_s16(vget_low_s16(v_row0), vget_high_s16(v_row0)),
                                            vaddl_s16(vget_low_s16(v_row1), vget_high_s16(v_row1)));
                vst1_s16(D, vmovn_s32(vshrq_n_s32(vaddq_s32(v_dst, v_2), 2)));
            }
        }

        return dx;
    }

private:
    int cn, step;
};

struct ResizeAreaFastVec_SIMD_32f
{
    ResizeAreaFastVec_SIMD_32f(int _scale_x, int _scale_y, int _cn, int _step) :
        cn(_cn), step(_step)
    {
        fast_mode = _scale_x == 2 && _scale_y == 2 && (cn == 1 || cn == 4);
    }

    int operator() (const float * S, float * D, int w) const
    {
        if (!fast_mode)
            return 0;

        const float * S0 = S, * S1 = (const float *)((const uchar *)(S0) + step);
        int dx = 0;

        float32x4_t v_025 = vdupq_n_f32(0.25f);

        if (cn == 1)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                float32x4x2_t v_row0 = vld2q_f32(S0), v_row1 = vld2q_f32(S1);

                float32x4_t v_dst0 = vaddq_f32(v_row0.val[0], v_row0.val[1]);
                float32x4_t v_dst1 = vaddq_f32(v_row1.val[0], v_row1.val[1]);

                vst1q_f32(D, vmulq_f32(vaddq_f32(v_dst0, v_dst1), v_025));
            }
        }
        else if (cn == 4)
        {
            for ( ; dx <= w - 4; dx += 4, S0 += 8, S1 += 8, D += 4)
            {
                float32x4_t v_dst0 = vaddq_f32(vld1q_f32(S0), vld1q_f32(S0 + 4));
                float32x4_t v_dst1 = vaddq_f32(vld1q_f32(S1), vld1q_f32(S1 + 4));

                vst1q_f32(D, vmulq_f32(vaddq_f32(v_dst0, v_dst1), v_025));
            }
        }

        return dx;
    }

private:
    int cn;
    bool fast_mode;
    int step;
};

#elif CV_SIMD

class ResizeAreaFastVec_SIMD_8u
{
public:
    ResizeAreaFastVec_SIMD_8u(int _cn, int _step) :
        cn(_cn), step(_step) {}

    int operator() (const uchar* S, uchar* D, int w) const
    {
        int dx = 0;
        const uchar* S0 = S;
        const uchar* S1 = S0 + step;

        if (cn == 1)
        {
            v_uint16 masklow = vx_setall_u16(0x00ff);
            for ( ; dx <= w - v_uint16::nlanes; dx += v_uint16::nlanes, S0 += v_uint8::nlanes, S1 += v_uint8::nlanes, D += v_uint16::nlanes)
            {
                v_uint16 r0 = v_reinterpret_as_u16(vx_load(S0));
                v_uint16 r1 = v_reinterpret_as_u16(vx_load(S1));
                v_rshr_pack_store<2>(D, (r0 >> 8) + (r0 & masklow) + (r1 >> 8) + (r1 & masklow));
            }
        }
        else if (cn == 3)
        {
            if (CV_SIMD_WIDTH > 64)
                return 0;
            for ( ; dx <= w - 3*v_uint8::nlanes; dx += 3*v_uint8::nlanes, S0 += 6*v_uint8::nlanes, S1 += 6*v_uint8::nlanes, D += 3*v_uint8::nlanes)
            {
                v_uint16 t0, t1, t2, t3, t4, t5;
                v_uint16 s0, s1, s2, s3, s4, s5;
                s0 = vx_load_expand(S0                     ) + vx_load_expand(S1                     );
                s1 = vx_load_expand(S0 +   v_uint16::nlanes) + vx_load_expand(S1 +   v_uint16::nlanes);
                s2 = vx_load_expand(S0 + 2*v_uint16::nlanes) + vx_load_expand(S1 + 2*v_uint16::nlanes);
                s3 = vx_load_expand(S0 + 3*v_uint16::nlanes) + vx_load_expand(S1 + 3*v_uint16::nlanes);
                s4 = vx_load_expand(S0 + 4*v_uint16::nlanes) + vx_load_expand(S1 + 4*v_uint16::nlanes);
                s5 = vx_load_expand(S0 + 5*v_uint16::nlanes) + vx_load_expand(S1 + 5*v_uint16::nlanes);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_uint16 bl, gl, rl;
#if CV_SIMD_WIDTH == 16
                bl = t0 + t3; gl = t1 + t4; rl = t2 + t5;
#elif CV_SIMD_WIDTH == 32
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                bl = s0 + s3; gl = s1 + s4; rl = s2 + s5;
#elif CV_SIMD_WIDTH == 64
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                bl = t0 + t3; gl = t1 + t4; rl = t2 + t5;
#endif
                s0 = vx_load_expand(S0 + 6*v_uint16::nlanes) + vx_load_expand(S1 + 6*v_uint16::nlanes);
                s1 = vx_load_expand(S0 + 7*v_uint16::nlanes) + vx_load_expand(S1 + 7*v_uint16::nlanes);
                s2 = vx_load_expand(S0 + 8*v_uint16::nlanes) + vx_load_expand(S1 + 8*v_uint16::nlanes);
                s3 = vx_load_expand(S0 + 9*v_uint16::nlanes) + vx_load_expand(S1 + 9*v_uint16::nlanes);
                s4 = vx_load_expand(S0 +10*v_uint16::nlanes) + vx_load_expand(S1 +10*v_uint16::nlanes);
                s5 = vx_load_expand(S0 +11*v_uint16::nlanes) + vx_load_expand(S1 +11*v_uint16::nlanes);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_uint16 bh, gh, rh;
#if CV_SIMD_WIDTH == 16
                bh = t0 + t3; gh = t1 + t4; rh = t2 + t5;
#elif CV_SIMD_WIDTH == 32
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                bh = s0 + s3; gh = s1 + s4; rh = s2 + s5;
#elif CV_SIMD_WIDTH == 64
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                bh = t0 + t3; gh = t1 + t4; rh = t2 + t5;
#endif
                v_store_interleave(D, v_rshr_pack<2>(bl, bh), v_rshr_pack<2>(gl, gh), v_rshr_pack<2>(rl, rh));
            }
        }
        else
        {
            CV_Assert(cn == 4);
            for ( ; dx <= w - v_uint8::nlanes; dx += v_uint8::nlanes, S0 += 2*v_uint8::nlanes, S1 += 2*v_uint8::nlanes, D += v_uint8::nlanes)
            {
                v_uint32 r00, r01, r10, r11;
                v_load_deinterleave((uint32_t*)S0, r00, r01);
                v_load_deinterleave((uint32_t*)S1, r10, r11);

                v_uint16 r00l, r01l, r10l, r11l, r00h, r01h, r10h, r11h;
                v_expand(v_reinterpret_as_u8(r00), r00l, r00h);
                v_expand(v_reinterpret_as_u8(r01), r01l, r01h);
                v_expand(v_reinterpret_as_u8(r10), r10l, r10h);
                v_expand(v_reinterpret_as_u8(r11), r11l, r11h);
                v_store(D, v_rshr_pack<2>(r00l + r01l + r10l + r11l, r00h + r01h + r10h + r11h));
            }
        }

        return dx;
    }

private:
    int cn;
    int step;
};

class ResizeAreaFastVec_SIMD_16u
{
public:
    ResizeAreaFastVec_SIMD_16u(int _cn, int _step) :
        cn(_cn), step(_step) {}

    int operator() (const ushort* S, ushort* D, int w) const
    {
        int dx = 0;
        const ushort* S0 = (const ushort*)S;
        const ushort* S1 = (const ushort*)((const uchar*)(S) + step);

        if (cn == 1)
        {
            v_uint32 masklow = vx_setall_u32(0x0000ffff);
            for (; dx <= w - v_uint32::nlanes; dx += v_uint32::nlanes, S0 += v_uint16::nlanes, S1 += v_uint16::nlanes, D += v_uint32::nlanes)
            {
                v_uint32 r0 = v_reinterpret_as_u32(vx_load(S0));
                v_uint32 r1 = v_reinterpret_as_u32(vx_load(S1));
                v_rshr_pack_store<2>(D, (r0 >> 16) + (r0 & masklow) + (r1 >> 16) + (r1 & masklow));
            }
        }
        else if (cn == 3)
        {
#if CV_SIMD_WIDTH == 16
            for ( ; dx <= w - 4; dx += 3, S0 += 6, S1 += 6, D += 3)
#if CV_SSE4_1
            {
                v_uint32 r0, r1, r2, r3;
                v_expand(vx_load(S0), r0, r1);
                v_expand(vx_load(S1), r2, r3);
                r0 += r2; r1 += r3;
                v_rshr_pack_store<2>(D, r0 + v_rotate_left<1>(r1, r0));
            }
#else
                v_rshr_pack_store<2>(D, v_load_expand(S0) + v_load_expand(S0 + 3) + v_load_expand(S1) + v_load_expand(S1 + 3));
#endif
#elif CV_SIMD_WIDTH == 32 || CV_SIMD_WIDTH == 64
            for ( ; dx <= w - 3*v_uint16::nlanes; dx += 3*v_uint16::nlanes, S0 += 6*v_uint16::nlanes, S1 += 6*v_uint16::nlanes, D += 3*v_uint16::nlanes)
            {
                v_uint32 t0, t1, t2, t3, t4, t5;
                v_uint32 s0, s1, s2, s3, s4, s5;
                s0 = vx_load_expand(S0                     ) + vx_load_expand(S1                     );
                s1 = vx_load_expand(S0 +   v_uint32::nlanes) + vx_load_expand(S1 +   v_uint32::nlanes);
                s2 = vx_load_expand(S0 + 2*v_uint32::nlanes) + vx_load_expand(S1 + 2*v_uint32::nlanes);
                s3 = vx_load_expand(S0 + 3*v_uint32::nlanes) + vx_load_expand(S1 + 3*v_uint32::nlanes);
                s4 = vx_load_expand(S0 + 4*v_uint32::nlanes) + vx_load_expand(S1 + 4*v_uint32::nlanes);
                s5 = vx_load_expand(S0 + 5*v_uint32::nlanes) + vx_load_expand(S1 + 5*v_uint32::nlanes);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_uint32 bl, gl, rl;
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
#if CV_SIMD_WIDTH == 32
                bl = t0 + t3; gl = t1 + t4; rl = t2 + t5;
#else //CV_SIMD_WIDTH == 64
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                bl = s0 + s3; gl = s1 + s4; rl = s2 + s5;
#endif
                s0 = vx_load_expand(S0 + 6*v_uint32::nlanes) + vx_load_expand(S1 + 6*v_uint32::nlanes);
                s1 = vx_load_expand(S0 + 7*v_uint32::nlanes) + vx_load_expand(S1 + 7*v_uint32::nlanes);
                s2 = vx_load_expand(S0 + 8*v_uint32::nlanes) + vx_load_expand(S1 + 8*v_uint32::nlanes);
                s3 = vx_load_expand(S0 + 9*v_uint32::nlanes) + vx_load_expand(S1 + 9*v_uint32::nlanes);
                s4 = vx_load_expand(S0 +10*v_uint32::nlanes) + vx_load_expand(S1 +10*v_uint32::nlanes);
                s5 = vx_load_expand(S0 +11*v_uint32::nlanes) + vx_load_expand(S1 +11*v_uint32::nlanes);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_uint32 bh, gh, rh;
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
#if CV_SIMD_WIDTH == 32
                bh = t0 + t3; gh = t1 + t4; rh = t2 + t5;
#else //CV_SIMD_WIDTH == 64
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                bh = s0 + s3; gh = s1 + s4; rh = s2 + s5;
#endif
                v_store_interleave(D, v_rshr_pack<2>(bl, bh), v_rshr_pack<2>(gl, gh), v_rshr_pack<2>(rl, rh));
            }
#elif CV_SIMD_WIDTH >= 64
            v_uint32 masklow = vx_setall_u32(0x0000ffff);
            for ( ; dx <= w - 3*v_uint16::nlanes; dx += 3*v_uint16::nlanes, S0 += 6*v_uint16::nlanes, S1 += 6*v_uint16::nlanes, D += 3*v_uint16::nlanes)
            {
                v_uint16 b0, g0, r0, b1, g1, r1;
                v_load_deinterleave(S0, b0, g0, r0);
                v_load_deinterleave(S1, b1, g1, r1);
                v_uint32 bl = (v_reinterpret_as_u32(b0) >> 16) + (v_reinterpret_as_u32(b0) & masklow) + (v_reinterpret_as_u32(b1) >> 16) + (v_reinterpret_as_u32(b1) & masklow);
                v_uint32 gl = (v_reinterpret_as_u32(g0) >> 16) + (v_reinterpret_as_u32(g0) & masklow) + (v_reinterpret_as_u32(g1) >> 16) + (v_reinterpret_as_u32(g1) & masklow);
                v_uint32 rl = (v_reinterpret_as_u32(r0) >> 16) + (v_reinterpret_as_u32(r0) & masklow) + (v_reinterpret_as_u32(r1) >> 16) + (v_reinterpret_as_u32(r1) & masklow);
                v_load_deinterleave(S0 + 3*v_uint16::nlanes, b0, g0, r0);
                v_load_deinterleave(S1 + 3*v_uint16::nlanes, b1, g1, r1);
                v_uint32 bh = (v_reinterpret_as_u32(b0) >> 16) + (v_reinterpret_as_u32(b0) & masklow) + (v_reinterpret_as_u32(b1) >> 16) + (v_reinterpret_as_u32(b1) & masklow);
                v_uint32 gh = (v_reinterpret_as_u32(g0) >> 16) + (v_reinterpret_as_u32(g0) & masklow) + (v_reinterpret_as_u32(g1) >> 16) + (v_reinterpret_as_u32(g1) & masklow);
                v_uint32 rh = (v_reinterpret_as_u32(r0) >> 16) + (v_reinterpret_as_u32(r0) & masklow) + (v_reinterpret_as_u32(r1) >> 16) + (v_reinterpret_as_u32(r1) & masklow);
                v_store_interleave(D, v_rshr_pack<2>(bl, bh), v_rshr_pack<2>(gl, gh), v_rshr_pack<2>(rl, rh));
            }
#endif
        }
        else
        {
            CV_Assert(cn == 4);
#if CV_SIMD_WIDTH >= 64
            for ( ; dx <= w - v_uint16::nlanes; dx += v_uint16::nlanes, S0 += 2*v_uint16::nlanes, S1 += 2*v_uint16::nlanes, D += v_uint16::nlanes)
            {
                v_uint64 r00, r01, r10, r11;
                v_load_deinterleave((uint64_t*)S0, r00, r01);
                v_load_deinterleave((uint64_t*)S1, r10, r11);

                v_uint32 r00l, r01l, r10l, r11l, r00h, r01h, r10h, r11h;
                v_expand(v_reinterpret_as_u16(r00), r00l, r00h);
                v_expand(v_reinterpret_as_u16(r01), r01l, r01h);
                v_expand(v_reinterpret_as_u16(r10), r10l, r10h);
                v_expand(v_reinterpret_as_u16(r11), r11l, r11h);
                v_store(D, v_rshr_pack<2>(r00l + r01l + r10l + r11l, r00h + r01h + r10h + r11h));
            }
#else
            for ( ; dx <= w - v_uint32::nlanes; dx += v_uint32::nlanes, S0 += v_uint16::nlanes, S1 += v_uint16::nlanes, D += v_uint32::nlanes)
            {
                v_uint32 r0, r1, r2, r3;
                v_expand(vx_load(S0), r0, r1);
                v_expand(vx_load(S1), r2, r3);
                r0 += r2; r1 += r3;
                v_uint32 v_d;
#if CV_SIMD_WIDTH == 16
                v_d = r0 + r1;
#elif CV_SIMD_WIDTH == 32
                v_uint32 t0, t1;
                v_recombine(r0, r1, t0, t1);
                v_d = t0 + t1;
#endif
                v_rshr_pack_store<2>(D, v_d);
            }
#endif
        }

        return dx;
    }

private:
    int cn;
    int step;
};

class ResizeAreaFastVec_SIMD_16s
{
public:
    ResizeAreaFastVec_SIMD_16s(int _cn, int _step) :
        cn(_cn), step(_step) {}

    int operator() (const short* S, short* D, int w) const
    {
        int dx = 0;
        const short* S0 = (const short*)S;
        const short* S1 = (const short*)((const uchar*)(S) + step);

        if (cn == 1)
        {
            v_int32 masklow = vx_setall_s32(0x0000ffff);
            for (; dx <= w - v_int32::nlanes; dx += v_int32::nlanes, S0 += v_int16::nlanes, S1 += v_int16::nlanes, D += v_int32::nlanes)
            {
                v_int32 r0 = v_reinterpret_as_s32(vx_load(S0));
                v_int32 r1 = v_reinterpret_as_s32(vx_load(S1));
                v_rshr_pack_store<2>(D, (r0 >> 16) + (((r0 & masklow)<<16)>>16) + (r1 >> 16) + (((r1 & masklow)<<16)>>16));
            }
        }
        else if (cn == 3)
        {
#if CV_SIMD_WIDTH == 16
            for ( ; dx <= w - 4; dx += 3, S0 += 6, S1 += 6, D += 3)
                v_rshr_pack_store<2>(D, v_load_expand(S0) + v_load_expand(S0 + 3) + v_load_expand(S1) + v_load_expand(S1 + 3));
#elif CV_SIMD_WIDTH == 32 || CV_SIMD_WIDTH == 64
            for ( ; dx <= w - 3*v_int16::nlanes; dx += 3*v_int16::nlanes, S0 += 6*v_int16::nlanes, S1 += 6*v_int16::nlanes, D += 3*v_int16::nlanes)
            {
                v_int32 t0, t1, t2, t3, t4, t5;
                v_int32 s0, s1, s2, s3, s4, s5;
                s0 = vx_load_expand(S0                    ) + vx_load_expand(S1                    );
                s1 = vx_load_expand(S0 +   v_int32::nlanes) + vx_load_expand(S1 +   v_int32::nlanes);
                s2 = vx_load_expand(S0 + 2*v_int32::nlanes) + vx_load_expand(S1 + 2*v_int32::nlanes);
                s3 = vx_load_expand(S0 + 3*v_int32::nlanes) + vx_load_expand(S1 + 3*v_int32::nlanes);
                s4 = vx_load_expand(S0 + 4*v_int32::nlanes) + vx_load_expand(S1 + 4*v_int32::nlanes);
                s5 = vx_load_expand(S0 + 5*v_int32::nlanes) + vx_load_expand(S1 + 5*v_int32::nlanes);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_int32 bl, gl, rl;
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
#if CV_SIMD_WIDTH == 32
                bl = t0 + t3; gl = t1 + t4; rl = t2 + t5;
#else //CV_SIMD_WIDTH == 64
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                bl = s0 + s3; gl = s1 + s4; rl = s2 + s5;
#endif
                s0 = vx_load_expand(S0 + 6*v_int32::nlanes) + vx_load_expand(S1 + 6*v_int32::nlanes);
                s1 = vx_load_expand(S0 + 7*v_int32::nlanes) + vx_load_expand(S1 + 7*v_int32::nlanes);
                s2 = vx_load_expand(S0 + 8*v_int32::nlanes) + vx_load_expand(S1 + 8*v_int32::nlanes);
                s3 = vx_load_expand(S0 + 9*v_int32::nlanes) + vx_load_expand(S1 + 9*v_int32::nlanes);
                s4 = vx_load_expand(S0 +10*v_int32::nlanes) + vx_load_expand(S1 +10*v_int32::nlanes);
                s5 = vx_load_expand(S0 +11*v_int32::nlanes) + vx_load_expand(S1 +11*v_int32::nlanes);
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                v_int32 bh, gh, rh;
                v_zip(s0, s3, t0, t1); v_zip(s1, s4, t2, t3); v_zip(s2, s5, t4, t5);
#if CV_SIMD_WIDTH == 32
                bh = t0 + t3; gh = t1 + t4; rh = t2 + t5;
#else //CV_SIMD_WIDTH == 64
                v_zip(t0, t3, s0, s1); v_zip(t1, t4, s2, s3); v_zip(t2, t5, s4, s5);
                bh = s0 + s3; gh = s1 + s4; rh = s2 + s5;
#endif
                v_store_interleave(D, v_rshr_pack<2>(bl, bh), v_rshr_pack<2>(gl, gh), v_rshr_pack<2>(rl, rh));
            }
#elif CV_SIMD_WIDTH >= 64
            for ( ; dx <= w - 3*v_int16::nlanes; dx += 3*v_int16::nlanes, S0 += 6*v_int16::nlanes, S1 += 6*v_int16::nlanes, D += 3*v_int16::nlanes)
            {
                v_int16 b0, g0, r0, b1, g1, r1;
                v_load_deinterleave(S0, b0, g0, r0);
                v_load_deinterleave(S1, b1, g1, r1);
                v_int32 bl = (v_reinterpret_as_s32(b0) >> 16) + ((v_reinterpret_as_s32(b0) << 16) >> 16) + (v_reinterpret_as_s32(b1) >> 16) + ((v_reinterpret_as_s32(b1) << 16) >> 16);
                v_int32 gl = (v_reinterpret_as_s32(g0) >> 16) + ((v_reinterpret_as_s32(g0) << 16) >> 16) + (v_reinterpret_as_s32(g1) >> 16) + ((v_reinterpret_as_s32(g1) << 16) >> 16);
                v_int32 rl = (v_reinterpret_as_s32(r0) >> 16) + ((v_reinterpret_as_s32(r0) << 16) >> 16) + (v_reinterpret_as_s32(r1) >> 16) + ((v_reinterpret_as_s32(r1) << 16) >> 16);
                v_load_deinterleave(S0 + 3*v_int16::nlanes, b0, g0, r0);
                v_load_deinterleave(S1 + 3*v_int16::nlanes, b1, g1, r1);
                v_int32 bh = (v_reinterpret_as_s32(b0) >> 16) + ((v_reinterpret_as_s32(b0) << 16) >> 16) + (v_reinterpret_as_s32(b1) >> 16) + ((v_reinterpret_as_s32(b1) << 16) >> 16);
                v_int32 gh = (v_reinterpret_as_s32(g0) >> 16) + ((v_reinterpret_as_s32(g0) << 16) >> 16) + (v_reinterpret_as_s32(g1) >> 16) + ((v_reinterpret_as_s32(g1) << 16) >> 16);
                v_int32 rh = (v_reinterpret_as_s32(r0) >> 16) + ((v_reinterpret_as_s32(r0) << 16) >> 16) + (v_reinterpret_as_s32(r1) >> 16) + ((v_reinterpret_as_s32(r1) << 16) >> 16);
                v_store_interleave(D, v_rshr_pack<2>(bl, bh), v_rshr_pack<2>(gl, gh), v_rshr_pack<2>(rl, rh));
            }
#endif
        }
        else
        {
            CV_Assert(cn == 4);
            for (; dx <= w - v_int16::nlanes; dx += v_int16::nlanes, S0 += 2 * v_int16::nlanes, S1 += 2 * v_int16::nlanes, D += v_int16::nlanes)
            {
#if CV_SIMD_WIDTH >= 64
                v_int64 r00, r01, r10, r11;
                v_load_deinterleave((int64_t*)S0, r00, r01);
                v_load_deinterleave((int64_t*)S1, r10, r11);

                v_int32 r00l, r01l, r10l, r11l, r00h, r01h, r10h, r11h;
                v_expand(v_reinterpret_as_s16(r00), r00l, r00h);
                v_expand(v_reinterpret_as_s16(r01), r01l, r01h);
                v_expand(v_reinterpret_as_s16(r10), r10l, r10h);
                v_expand(v_reinterpret_as_s16(r11), r11l, r11h);
                v_store(D, v_rshr_pack<2>(r00l + r01l + r10l + r11l, r00h + r01h + r10h + r11h));
#else
                v_int32 r0, r1, r2, r3;
                r0 = vx_load_expand(S0                    ) + vx_load_expand(S1                    );
                r1 = vx_load_expand(S0 +   v_int32::nlanes) + vx_load_expand(S1 +   v_int32::nlanes);
                r2 = vx_load_expand(S0 + 2*v_int32::nlanes) + vx_load_expand(S1 + 2*v_int32::nlanes);
                r3 = vx_load_expand(S0 + 3*v_int32::nlanes) + vx_load_expand(S1 + 3*v_int32::nlanes);
                v_int32 dl, dh;
#if CV_SIMD_WIDTH == 16
                dl = r0 + r1; dh = r2 + r3;
#elif CV_SIMD_WIDTH == 32
                v_int32 t0, t1, t2, t3;
                v_recombine(r0, r1, t0, t1); v_recombine(r2, r3, t2, t3);
                dl = t0 + t1; dh = t2 + t3;
#endif
                v_store(D, v_rshr_pack<2>(dl, dh));
#endif
            }
        }

        return dx;
    }

private:
    int cn;
    int step;
};

struct ResizeAreaFastVec_SIMD_32f
{
    ResizeAreaFastVec_SIMD_32f(int _scale_x, int _scale_y, int _cn, int _step) :
        cn(_cn), step(_step)
    {
        fast_mode = _scale_x == 2 && _scale_y == 2 && (cn == 1 || cn == 4);
    }

    int operator() (const float * S, float * D, int w) const
    {
        if (!fast_mode)
            return 0;

        const float * S0 = S, * S1 = (const float *)((const uchar *)(S0) + step);
        int dx = 0;

        if (cn == 1)
        {
            v_float32 v_025 = vx_setall_f32(0.25f);
            for ( ; dx <= w - v_float32::nlanes; dx += v_float32::nlanes, S0 += 2*v_float32::nlanes, S1 += 2*v_float32::nlanes, D += v_float32::nlanes)
            {
                v_float32 v_row00, v_row01, v_row10, v_row11;
                v_load_deinterleave(S0, v_row00, v_row01);
                v_load_deinterleave(S1, v_row10, v_row11);
                v_store(D, ((v_row00 + v_row01) + (v_row10 + v_row11)) * v_025);
            }
        }
        else if (cn == 4)
        {
#if CV_SIMD_WIDTH == 16
            v_float32 v_025 = vx_setall_f32(0.25f);
            for (; dx <= w - v_float32::nlanes; dx += v_float32::nlanes, S0 += 2*v_float32::nlanes, S1 += 2*v_float32::nlanes, D += v_float32::nlanes)
                v_store(D, ((vx_load(S0) + vx_load(S0 + v_float32::nlanes)) + (vx_load(S1) + vx_load(S1 + v_float32::nlanes))) * v_025);
#elif CV_SIMD256
            v_float32x8 v_025 = v256_setall_f32(0.25f);
            for (; dx <= w - v_float32x8::nlanes; dx += v_float32x8::nlanes, S0 += 2*v_float32x8::nlanes, S1 += 2*v_float32x8::nlanes, D += v_float32x8::nlanes)
            {
                v_float32x8 dst0, dst1;
                v_recombine(v256_load(S0) + v256_load(S1), v256_load(S0 + v_float32x8::nlanes) + v256_load(S1 + v_float32x8::nlanes), dst0, dst1);
                v_store(D, (dst0 + dst1) * v_025);
            }
#endif
        }

        return dx;
    }

private:
    int cn;
    bool fast_mode;
    int step;
};

#else

typedef ResizeAreaFastNoVec<uchar, uchar> ResizeAreaFastVec_SIMD_8u;
typedef ResizeAreaFastNoVec<ushort, ushort> ResizeAreaFastVec_SIMD_16u;
typedef ResizeAreaFastNoVec<short, short> ResizeAreaFastVec_SIMD_16s;
typedef ResizeAreaFastNoVec<float, float> ResizeAreaFastVec_SIMD_32f;

#endif

template<typename T, typename SIMDVecOp>
struct ResizeAreaFastVec
{
    ResizeAreaFastVec(int _scale_x, int _scale_y, int _cn, int _step) :
        scale_x(_scale_x), scale_y(_scale_y), cn(_cn), step(_step), vecOp(_cn, _step)
    {
        fast_mode = scale_x == 2 && scale_y == 2 && (cn == 1 || cn == 3 || cn == 4);
    }

    int operator() (const T* S, T* D, int w) const
    {
        if (!fast_mode)
            return 0;

        const T* nextS = (const T*)((const uchar*)S + step);
        int dx = vecOp(S, D, w);

        if (cn == 1)
            for( ; dx < w; ++dx )
            {
                int index = dx*2;
                D[dx] = (T)((S[index] + S[index+1] + nextS[index] + nextS[index+1] + 2) >> 2);
            }
        else if (cn == 3)
            for( ; dx < w; dx += 3 )
            {
                int index = dx*2;
                D[dx] = (T)((S[index] + S[index+3] + nextS[index] + nextS[index+3] + 2) >> 2);
                D[dx+1] = (T)((S[index+1] + S[index+4] + nextS[index+1] + nextS[index+4] + 2) >> 2);
                D[dx+2] = (T)((S[index+2] + S[index+5] + nextS[index+2] + nextS[index+5] + 2) >> 2);
            }
        else
            {
                CV_Assert(cn == 4);
                for( ; dx < w; dx += 4 )
                {
                    int index = dx*2;
                    D[dx] = (T)((S[index] + S[index+4] + nextS[index] + nextS[index+4] + 2) >> 2);
                    D[dx+1] = (T)((S[index+1] + S[index+5] + nextS[index+1] + nextS[index+5] + 2) >> 2);
                    D[dx+2] = (T)((S[index+2] + S[index+6] + nextS[index+2] + nextS[index+6] + 2) >> 2);
                    D[dx+3] = (T)((S[index+3] + S[index+7] + nextS[index+3] + nextS[index+7] + 2) >> 2);
                }
            }

        return dx;
    }

private:
    int scale_x, scale_y;
    int cn;
    bool fast_mode;
    int step;
    SIMDVecOp vecOp;
};

template <typename T, typename WT, typename VecOp>
class resizeAreaFast_Invoker :
    public ParallelLoopBody
{
public:
    resizeAreaFast_Invoker(const Mat &_src, Mat &_dst,
        int _scale_x, int _scale_y, const int* _ofs, const int* _xofs) :
        ParallelLoopBody(), src(_src), dst(_dst), scale_x(_scale_x),
        scale_y(_scale_y), ofs(_ofs), xofs(_xofs)
    {
    }

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        Size ssize = src.size(), dsize = dst.size();
        int cn = src.channels();
        int area = scale_x*scale_y;
        float scale = 1.f/(area);
        int dwidth1 = (ssize.width/scale_x)*cn;
        dsize.width *= cn;
        ssize.width *= cn;
        int dy, dx, k = 0;

        VecOp vop(scale_x, scale_y, src.channels(), (int)src.step/*, area_ofs*/);

        for( dy = range.start; dy < range.end; dy++ )
        {
            T* D = (T*)(dst.data + dst.step*dy);
            int sy0 = dy*scale_y;
            int w = sy0 + scale_y <= ssize.height ? dwidth1 : 0;

            if( sy0 >= ssize.height )
            {
                for( dx = 0; dx < dsize.width; dx++ )
                    D[dx] = 0;
                continue;
            }

            dx = vop(src.template ptr<T>(sy0), D, w);
            for( ; dx < w; dx++ )
            {
                const T* S = src.template ptr<T>(sy0) + xofs[dx];
                WT sum = 0;
                k = 0;
                #if CV_ENABLE_UNROLLED
                for( ; k <= area - 4; k += 4 )
                    sum += S[ofs[k]] + S[ofs[k+1]] + S[ofs[k+2]] + S[ofs[k+3]];
                #endif
                for( ; k < area; k++ )
                    sum += S[ofs[k]];

                D[dx] = saturate_cast<T>(sum * scale);
            }

            for( ; dx < dsize.width; dx++ )
            {
                WT sum = 0;
                int count = 0, sx0 = xofs[dx];
                if( sx0 >= ssize.width )
                    D[dx] = 0;

                for( int sy = 0; sy < scale_y; sy++ )
                {
                    if( sy0 + sy >= ssize.height )
                        break;
                    const T* S = src.template ptr<T>(sy0 + sy) + sx0;
                    for( int sx = 0; sx < scale_x*cn; sx += cn )
                    {
                        if( sx0 + sx >= ssize.width )
                            break;
                        sum += S[sx];
                        count++;
                    }
                }

                D[dx] = saturate_cast<T>((float)sum/count);
            }
        }
    }

private:
    Mat src;
    Mat dst;
    int scale_x, scale_y;
    const int *ofs, *xofs;
};

template<typename T, typename WT, typename VecOp>
static void resizeAreaFast_( const Mat& src, Mat& dst, const int* ofs, const int* xofs,
                             int scale_x, int scale_y )
{
    Range range(0, dst.rows);
    resizeAreaFast_Invoker<T, WT, VecOp> invoker(src, dst, scale_x,
        scale_y, ofs, xofs);
    parallel_for_(range, invoker, dst.total()/(double)(1<<16));
}

struct DecimateAlpha
{
    int si, di;
    float alpha;
};


template<typename T, typename WT> class ResizeArea_Invoker :
    public ParallelLoopBody
{
public:
    ResizeArea_Invoker( const Mat& _src, Mat& _dst,
                        const DecimateAlpha* _xtab, int _xtab_size,
                        const DecimateAlpha* _ytab, int _ytab_size,
                        const int* _tabofs )
    {
        src = &_src;
        dst = &_dst;
        xtab0 = _xtab;
        xtab_size0 = _xtab_size;
        ytab = _ytab;
        ytab_size = _ytab_size;
        tabofs = _tabofs;
    }

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        Size dsize = dst->size();
        int cn = dst->channels();
        dsize.width *= cn;
        AutoBuffer<WT> _buffer(dsize.width*2);
        const DecimateAlpha* xtab = xtab0;
        int xtab_size = xtab_size0;
        WT *buf = _buffer.data(), *sum = buf + dsize.width;
        int j_start = tabofs[range.start], j_end = tabofs[range.end], j, k, dx, prev_dy = ytab[j_start].di;

        for( dx = 0; dx < dsize.width; dx++ )
            sum[dx] = (WT)0;

        for( j = j_start; j < j_end; j++ )
        {
            WT beta = ytab[j].alpha;
            int dy = ytab[j].di;
            int sy = ytab[j].si;

            {
                const T* S = src->template ptr<T>(sy);
                for( dx = 0; dx < dsize.width; dx++ )
                    buf[dx] = (WT)0;

                if( cn == 1 )
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        buf[dxn] += S[xtab[k].si]*alpha;
                    }
                else if( cn == 2 )
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        WT t0 = buf[dxn] + S[sxn]*alpha;
                        WT t1 = buf[dxn+1] + S[sxn+1]*alpha;
                        buf[dxn] = t0; buf[dxn+1] = t1;
                    }
                else if( cn == 3 )
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        WT t0 = buf[dxn] + S[sxn]*alpha;
                        WT t1 = buf[dxn+1] + S[sxn+1]*alpha;
                        WT t2 = buf[dxn+2] + S[sxn+2]*alpha;
                        buf[dxn] = t0; buf[dxn+1] = t1; buf[dxn+2] = t2;
                    }
                else if( cn == 4 )
                {
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        WT t0 = buf[dxn] + S[sxn]*alpha;
                        WT t1 = buf[dxn+1] + S[sxn+1]*alpha;
                        buf[dxn] = t0; buf[dxn+1] = t1;
                        t0 = buf[dxn+2] + S[sxn+2]*alpha;
                        t1 = buf[dxn+3] + S[sxn+3]*alpha;
                        buf[dxn+2] = t0; buf[dxn+3] = t1;
                    }
                }
                else
                {
                    for( k = 0; k < xtab_size; k++ )
                    {
                        int sxn = xtab[k].si;
                        int dxn = xtab[k].di;
                        WT alpha = xtab[k].alpha;
                        for( int c = 0; c < cn; c++ )
                            buf[dxn + c] += S[sxn + c]*alpha;
                    }
                }
            }

            if( dy != prev_dy )
            {
                T* D = dst->template ptr<T>(prev_dy);

                for( dx = 0; dx < dsize.width; dx++ )
                {
                    D[dx] = saturate_cast<T>(sum[dx]);
                    sum[dx] = beta*buf[dx];
                }
                prev_dy = dy;
            }
            else
            {
                for( dx = 0; dx < dsize.width; dx++ )
                    sum[dx] += beta*buf[dx];
            }
        }

        {
        T* D = dst->template ptr<T>(prev_dy);
        for( dx = 0; dx < dsize.width; dx++ )
            D[dx] = saturate_cast<T>(sum[dx]);
        }
    }

private:
    const Mat* src;
    Mat* dst;
    const DecimateAlpha* xtab0;
    const DecimateAlpha* ytab;
    int xtab_size0, ytab_size;
    const int* tabofs;
};


template <typename T, typename WT>
static void resizeArea_( const Mat& src, Mat& dst,
                         const DecimateAlpha* xtab, int xtab_size,
                         const DecimateAlpha* ytab, int ytab_size,
                         const int* tabofs )
{
    parallel_for_(Range(0, dst.rows),
                 ResizeArea_Invoker<T, WT>(src, dst, xtab, xtab_size, ytab, ytab_size, tabofs),
                 dst.total()/((double)(1 << 16)));
}


typedef void (*ResizeFunc)( const Mat& src, Mat& dst,
                            const int* xofs, const void* alpha,
                            const int* yofs, const void* beta,
                            int xmin, int xmax, int ksize );

typedef void (*ResizeAreaFastFunc)( const Mat& src, Mat& dst,
                                    const int* ofs, const int *xofs,
                                    int scale_x, int scale_y );

typedef void (*ResizeAreaFunc)( const Mat& src, Mat& dst,
                                const DecimateAlpha* xtab, int xtab_size,
                                const DecimateAlpha* ytab, int ytab_size,
                                const int* yofs);


static int computeResizeAreaTab( int ssize, int dsize, int cn, double scale, DecimateAlpha* tab )
{
    int k = 0;
    for(int dx = 0; dx < dsize; dx++ )
    {
        double fsx1 = dx * scale;
        double fsx2 = fsx1 + scale;
        double cellWidth = std::min(scale, ssize - fsx1);

        int sx1 = cvCeil(fsx1), sx2 = cvFloor(fsx2);

        sx2 = std::min(sx2, ssize - 1);
        sx1 = std::min(sx1, sx2);

        if( sx1 - fsx1 > 1e-3 )
        {
            assert( k < ssize*2 );
            tab[k].di = dx * cn;
            tab[k].si = (sx1 - 1) * cn;
            tab[k++].alpha = (float)((sx1 - fsx1) / cellWidth);
        }

        for(int sx = sx1; sx < sx2; sx++ )
        {
            assert( k < ssize*2 );
            tab[k].di = dx * cn;
            tab[k].si = sx * cn;
            tab[k++].alpha = float(1.0 / cellWidth);
        }

        if( fsx2 - sx2 > 1e-3 )
        {
            assert( k < ssize*2 );
            tab[k].di = dx * cn;
            tab[k].si = sx2 * cn;
            tab[k++].alpha = (float)(std::min(std::min(fsx2 - sx2, 1.), cellWidth) / cellWidth);
        }
    }
    return k;
}

#ifdef HAVE_OPENCL
static void ocl_computeResizeAreaTabs(int ssize, int dsize, double scale, int * const map_tab,
                                      float * const alpha_tab, int * const ofs_tab)
{
    int k = 0, dx = 0;
    for ( ; dx < dsize; dx++)
    {
        ofs_tab[dx] = k;

        double fsx1 = dx * scale;
        double fsx2 = fsx1 + scale;
        double cellWidth = std::min(scale, ssize - fsx1);

        int sx1 = cvCeil(fsx1), sx2 = cvFloor(fsx2);

        sx2 = std::min(sx2, ssize - 1);
        sx1 = std::min(sx1, sx2);

        if (sx1 - fsx1 > 1e-3)
        {
            map_tab[k] = sx1 - 1;
            alpha_tab[k++] = (float)((sx1 - fsx1) / cellWidth);
        }

        for (int sx = sx1; sx < sx2; sx++)
        {
            map_tab[k] = sx;
            alpha_tab[k++] = float(1.0 / cellWidth);
        }

        if (fsx2 - sx2 > 1e-3)
        {
            map_tab[k] = sx2;
            alpha_tab[k++] = (float)(std::min(std::min(fsx2 - sx2, 1.), cellWidth) / cellWidth);
        }
    }
    ofs_tab[dx] = k;
}

static bool ocl_resize( InputArray _src, OutputArray _dst, Size dsize,
                        double fx, double fy, int interpolation)
{
    int type = _src.type(), depth = CV_MAT_DEPTH(type), cn = CV_MAT_CN(type);

    double inv_fx = 1.0 / fx, inv_fy = 1.0 / fy;
    float inv_fxf = (float)inv_fx, inv_fyf = (float)inv_fy;
    int iscale_x = saturate_cast<int>(inv_fx), iscale_y = saturate_cast<int>(inv_fx);
    bool is_area_fast = std::abs(inv_fx - iscale_x) < DBL_EPSILON &&
        std::abs(inv_fy - iscale_y) < DBL_EPSILON;

    // in case of scale_x && scale_y is equal to 2
    // INTER_AREA (fast) also is equal to INTER_LINEAR
    if( interpolation == INTER_LINEAR && is_area_fast && iscale_x == 2 && iscale_y == 2 )
        /*interpolation = INTER_AREA*/CV_UNUSED(0); // INTER_AREA is slower

    if( !(cn <= 4 &&
           (interpolation == INTER_NEAREST || interpolation == INTER_LINEAR ||
            (interpolation == INTER_AREA && inv_fx >= 1 && inv_fy >= 1) )) )
        return false;

    UMat src = _src.getUMat();
    _dst.create(dsize, type);
    UMat dst = _dst.getUMat();

    Size ssize = src.size();
    ocl::Kernel k;
    size_t globalsize[] = { (size_t)dst.cols, (size_t)dst.rows };

    ocl::Image2D srcImage;

    // See if this could be done with a sampler.  We stick with integer
    // datatypes because the observed error is low.
    bool useSampler = (interpolation == INTER_LINEAR && ocl::Device::getDefault().imageSupport() &&
                       ocl::Image2D::canCreateAlias(src) && depth <= 4 &&
                       ocl::Image2D::isFormatSupported(depth, cn, true) &&
                       src.offset==0);
    if (useSampler)
    {
        int wdepth = std::max(depth, CV_32S);
        char buf[2][32];
        cv::String compileOpts = format("-D USE_SAMPLER -D depth=%d -D T=%s -D T1=%s "
                        "-D convertToDT=%s -D cn=%d",
                        depth, ocl::typeToStr(type), ocl::typeToStr(depth),
                        ocl::convertTypeStr(wdepth, depth, cn, buf[1]),
                        cn);
        k.create("resizeSampler", ocl::imgproc::resize_oclsrc, compileOpts);

        if (k.empty())
            useSampler = false;
        else
        {
            // Convert the input into an OpenCL image type, using normalized channel data types
            // and aliasing the UMat.
            srcImage = ocl::Image2D(src, true, true);
            k.args(srcImage, ocl::KernelArg::WriteOnly(dst),
                   (float)inv_fx, (float)inv_fy);
        }
    }

    if (interpolation == INTER_LINEAR && !useSampler)
    {
        char buf[2][32];

        // integer path is slower because of CPU part, so it's disabled
        if (depth == CV_8U && ((void)0, 0))
        {
            AutoBuffer<uchar> _buffer((dsize.width + dsize.height)*(sizeof(int) + sizeof(short)*2));
            int* xofs = (int*)_buffer.data(), * yofs = xofs + dsize.width;
            short* ialpha = (short*)(yofs + dsize.height), * ibeta = ialpha + dsize.width*2;
            float fxx, fyy;
            int sx, sy;

            for (int dx = 0; dx < dsize.width; dx++)
            {
                fxx = (float)((dx+0.5)*inv_fx - 0.5);
                sx = cvFloor(fxx);
                fxx -= sx;

                if (sx < 0)
                    fxx = 0, sx = 0;

                if (sx >= ssize.width-1)
                    fxx = 0, sx = ssize.width-1;

                xofs[dx] = sx;
                ialpha[dx*2 + 0] = saturate_cast<short>((1.f - fxx) * INTER_RESIZE_COEF_SCALE);
                ialpha[dx*2 + 1] = saturate_cast<short>(fxx         * INTER_RESIZE_COEF_SCALE);
            }

            for (int dy = 0; dy < dsize.height; dy++)
            {
                fyy = (float)((dy+0.5)*inv_fy - 0.5);
                sy = cvFloor(fyy);
                fyy -= sy;

                yofs[dy] = sy;
                ibeta[dy*2 + 0] = saturate_cast<short>((1.f - fyy) * INTER_RESIZE_COEF_SCALE);
                ibeta[dy*2 + 1] = saturate_cast<short>(fyy         * INTER_RESIZE_COEF_SCALE);
            }

            int wdepth = std::max(depth, CV_32S), wtype = CV_MAKETYPE(wdepth, cn);
            UMat coeffs;
            Mat(1, static_cast<int>(_buffer.size()), CV_8UC1, _buffer.data()).copyTo(coeffs);

            k.create("resizeLN", ocl::imgproc::resize_oclsrc,
                     format("-D INTER_LINEAR_INTEGER -D depth=%d -D T=%s -D T1=%s "
                            "-D WT=%s -D convertToWT=%s -D convertToDT=%s -D cn=%d "
                            "-D INTER_RESIZE_COEF_BITS=%d",
                            depth, ocl::typeToStr(type), ocl::typeToStr(depth), ocl::typeToStr(wtype),
                            ocl::convertTypeStr(depth, wdepth, cn, buf[0]),
                            ocl::convertTypeStr(wdepth, depth, cn, buf[1]),
                            cn, INTER_RESIZE_COEF_BITS));
            if (k.empty())
                return false;

            k.args(ocl::KernelArg::ReadOnly(src), ocl::KernelArg::WriteOnly(dst),
                   ocl::KernelArg::PtrReadOnly(coeffs));
        }
        else
        {
            int wdepth = std::max(depth, CV_32S), wtype = CV_MAKETYPE(wdepth, cn);
            k.create("resizeLN", ocl::imgproc::resize_oclsrc,
                     format("-D INTER_LINEAR -D depth=%d -D T=%s -D T1=%s "
                            "-D WT=%s -D convertToWT=%s -D convertToDT=%s -D cn=%d "
                            "-D INTER_RESIZE_COEF_BITS=%d",
                            depth, ocl::typeToStr(type), ocl::typeToStr(depth), ocl::typeToStr(wtype),
                            ocl::convertTypeStr(depth, wdepth, cn, buf[0]),
                            ocl::convertTypeStr(wdepth, depth, cn, buf[1]),
                            cn, INTER_RESIZE_COEF_BITS));
            if (k.empty())
                return false;

            k.args(ocl::KernelArg::ReadOnly(src), ocl::KernelArg::WriteOnly(dst),
                   (float)inv_fx, (float)inv_fy);
        }
    }
    else if (interpolation == INTER_NEAREST)
    {
        k.create("resizeNN", ocl::imgproc::resize_oclsrc,
                 format("-D INTER_NEAREST -D T=%s -D T1=%s -D cn=%d",
                        ocl::vecopTypeToStr(type), ocl::vecopTypeToStr(depth), cn));
        if (k.empty())
            return false;

        k.args(ocl::KernelArg::ReadOnly(src), ocl::KernelArg::WriteOnly(dst),
               (float)inv_fx, (float)inv_fy);
    }
    else if (interpolation == INTER_AREA)
    {
        int wdepth = std::max(depth, is_area_fast ? CV_32S : CV_32F);
        int wtype = CV_MAKE_TYPE(wdepth, cn);

        char cvt[2][40];
        String buildOption = format("-D INTER_AREA -D T=%s -D T1=%s -D WTV=%s -D convertToWTV=%s -D cn=%d",
                                    ocl::typeToStr(type), ocl::typeToStr(depth), ocl::typeToStr(wtype),
                                    ocl::convertTypeStr(depth, wdepth, cn, cvt[0]), cn);

        UMat alphaOcl, tabofsOcl, mapOcl;
        UMat dmap, smap;

        if (is_area_fast)
        {
            int wdepth2 = std::max(CV_32F, depth), wtype2 = CV_MAKE_TYPE(wdepth2, cn);
            buildOption = buildOption + format(" -D convertToT=%s -D WT2V=%s -D convertToWT2V=%s -D INTER_AREA_FAST"
                                                " -D XSCALE=%d -D YSCALE=%d -D SCALE=%ff",
                                                ocl::convertTypeStr(wdepth2, depth, cn, cvt[0]),
                                                ocl::typeToStr(wtype2), ocl::convertTypeStr(wdepth, wdepth2, cn, cvt[1]),
                                    iscale_x, iscale_y, 1.0f / (iscale_x * iscale_y));

            k.create("resizeAREA_FAST", ocl::imgproc::resize_oclsrc, buildOption);
            if (k.empty())
                return false;
        }
        else
        {
            buildOption = buildOption + format(" -D convertToT=%s", ocl::convertTypeStr(wdepth, depth, cn, cvt[0]));
            k.create("resizeAREA", ocl::imgproc::resize_oclsrc, buildOption);
            if (k.empty())
                return false;

            int xytab_size = (ssize.width + ssize.height) << 1;
            int tabofs_size = dsize.height + dsize.width + 2;

            AutoBuffer<int> _xymap_tab(xytab_size), _xyofs_tab(tabofs_size);
            AutoBuffer<float> _xyalpha_tab(xytab_size);
            int * xmap_tab = _xymap_tab.data(), * ymap_tab = _xymap_tab.data() + (ssize.width << 1);
            float * xalpha_tab = _xyalpha_tab.data(), * yalpha_tab = _xyalpha_tab.data() + (ssize.width << 1);
            int * xofs_tab = _xyofs_tab.data(), * yofs_tab = _xyofs_tab.data() + dsize.width + 1;

            ocl_computeResizeAreaTabs(ssize.width, dsize.width, inv_fx, xmap_tab, xalpha_tab, xofs_tab);
            ocl_computeResizeAreaTabs(ssize.height, dsize.height, inv_fy, ymap_tab, yalpha_tab, yofs_tab);

            // loading precomputed arrays to GPU
            Mat(1, xytab_size, CV_32FC1, _xyalpha_tab.data()).copyTo(alphaOcl);
            Mat(1, xytab_size, CV_32SC1, _xymap_tab.data()).copyTo(mapOcl);
            Mat(1, tabofs_size, CV_32SC1, _xyofs_tab.data()).copyTo(tabofsOcl);
        }

        ocl::KernelArg srcarg = ocl::KernelArg::ReadOnly(src), dstarg = ocl::KernelArg::WriteOnly(dst);

        if (is_area_fast)
            k.args(srcarg, dstarg);
        else
            k.args(srcarg, dstarg, inv_fxf, inv_fyf, ocl::KernelArg::PtrReadOnly(tabofsOcl),
                   ocl::KernelArg::PtrReadOnly(mapOcl), ocl::KernelArg::PtrReadOnly(alphaOcl));

        return k.run(2, globalsize, NULL, false);
    }

    return k.run(2, globalsize, 0, false);
}

#endif

#ifdef HAVE_IPP
#define IPP_RESIZE_PARALLEL 1

#ifdef HAVE_IPP_IW
class ipp_resizeParallel: public ParallelLoopBody
{
public:
    ipp_resizeParallel(::ipp::IwiImage &src, ::ipp::IwiImage &dst, bool &ok):
        m_src(src), m_dst(dst), m_ok(ok) {}
    ~ipp_resizeParallel()
    {
    }

    void Init(IppiInterpolationType inter)
    {
        iwiResize.InitAlloc(m_src.m_size, m_dst.m_size, m_src.m_dataType, m_src.m_channels, inter, ::ipp::IwiResizeParams(0, 0, 0.75, 4), ippBorderRepl);

        m_ok = true;
    }

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        CV_INSTRUMENT_REGION_IPP();

        if(!m_ok)
            return;

        try
        {
            ::ipp::IwiTile tile = ::ipp::IwiRoi(0, range.start, m_dst.m_size.width, range.end - range.start);
            CV_INSTRUMENT_FUN_IPP(iwiResize, m_src, m_dst, ippBorderRepl, tile);
        }
        catch(const ::ipp::IwException &)
        {
            m_ok = false;
            return;
        }
    }
private:
    ::ipp::IwiImage &m_src;
    ::ipp::IwiImage &m_dst;

    mutable ::ipp::IwiResize iwiResize;

    volatile bool &m_ok;
    const ipp_resizeParallel& operator= (const ipp_resizeParallel&);
};

class ipp_resizeAffineParallel: public ParallelLoopBody
{
public:
    ipp_resizeAffineParallel(::ipp::IwiImage &src, ::ipp::IwiImage &dst, bool &ok):
        m_src(src), m_dst(dst), m_ok(ok) {}
    ~ipp_resizeAffineParallel()
    {
    }

    void Init(IppiInterpolationType inter, double scaleX, double scaleY)
    {
        double shift = (inter == ippNearest)?-1e-10:-0.5;
        double coeffs[2][3] = {
            {scaleX, 0,      shift+0.5*scaleX},
            {0,      scaleY, shift+0.5*scaleY}
        };

        iwiWarpAffine.InitAlloc(m_src.m_size, m_dst.m_size, m_src.m_dataType, m_src.m_channels, coeffs, iwTransForward, inter, ::ipp::IwiWarpAffineParams(0, 0, 0.75), ippBorderRepl);

        m_ok = true;
    }

    virtual void operator() (const Range& range) const CV_OVERRIDE
    {
        CV_INSTRUMENT_REGION_IPP();

        if(!m_ok)
            return;

        try
        {
            ::ipp::IwiTile tile = ::ipp::IwiRoi(0, range.start, m_dst.m_size.width, range.end - range.start);
            CV_INSTRUMENT_FUN_IPP(iwiWarpAffine, m_src, m_dst, tile);
        }
        catch(const ::ipp::IwException &)
        {
            m_ok = false;
            return;
        }
    }
private:
    ::ipp::IwiImage &m_src;
    ::ipp::IwiImage &m_dst;

    mutable ::ipp::IwiWarpAffine iwiWarpAffine;

    volatile bool &m_ok;
    const ipp_resizeAffineParallel& operator= (const ipp_resizeAffineParallel&);
};
#endif

static bool ipp_resize(const uchar * src_data, size_t src_step, int src_width, int src_height,
            uchar * dst_data, size_t dst_step, int dst_width, int dst_height, double inv_scale_x, double inv_scale_y,
            int depth, int channels, int interpolation)
{
#ifdef HAVE_IPP_IW
    CV_INSTRUMENT_REGION_IPP();

    IppDataType           ippDataType = ippiGetDataType(depth);
    IppiInterpolationType ippInter    = ippiGetInterpolation(interpolation);
    if((int)ippInter < 0)
        return false;

    // Resize which doesn't match OpenCV exactly
    if (!cv::ipp::useIPP_NotExact())
    {
        if (ippInter == ippNearest || ippInter == ippSuper || (ippDataType == ipp8u && ippInter == ippLinear))
            return false;
    }

    if(ippInter != ippLinear && ippDataType == ipp64f)
        return false;

#if IPP_VERSION_X100 < 201801
    // Degradations on int^2 linear downscale
    if (ippDataType != ipp64f && ippInter == ippLinear && inv_scale_x < 1 && inv_scale_y < 1) // if downscale
    {
        int scale_x = (int)(1 / inv_scale_x);
        int scale_y = (int)(1 / inv_scale_y);
        if (1 / inv_scale_x - scale_x < DBL_EPSILON && 1 / inv_scale_y - scale_y < DBL_EPSILON) // if integer
        {
            if (!(scale_x&(scale_x - 1)) && !(scale_y&(scale_y - 1))) // if power of 2
                return false;
        }
    }
#endif

    bool  affine = false;
    const double IPP_RESIZE_EPS = (depth == CV_64F)?0:1e-10;
    double ex = fabs((double)dst_width / src_width  - inv_scale_x) / inv_scale_x;
    double ey = fabs((double)dst_height / src_height - inv_scale_y) / inv_scale_y;

    // Use affine transform resize to allow sub-pixel accuracy
    if(ex > IPP_RESIZE_EPS || ey > IPP_RESIZE_EPS)
        affine = true;

    // Affine doesn't support Lanczos and Super interpolations
    if(affine && (ippInter == ippLanczos || ippInter == ippSuper))
        return false;

    try
    {
        ::ipp::IwiImage iwSrc(::ipp::IwiSize(src_width, src_height), ippDataType, channels, 0, (void*)src_data, src_step);
        ::ipp::IwiImage iwDst(::ipp::IwiSize(dst_width, dst_height), ippDataType, channels, 0, (void*)dst_data, dst_step);

        bool  ok;
        int   threads = ippiSuggestThreadsNum(iwDst, 1+((double)(src_width*src_height)/(dst_width*dst_height)));
        Range range(0, dst_height);
        ipp_resizeParallel       invokerGeneral(iwSrc, iwDst, ok);
        ipp_resizeAffineParallel invokerAffine(iwSrc, iwDst, ok);
        ParallelLoopBody        *pInvoker = NULL;
        if(affine)
        {
            pInvoker = &invokerAffine;
            invokerAffine.Init(ippInter, inv_scale_x, inv_scale_y);
        }
        else
        {
            pInvoker = &invokerGeneral;
            invokerGeneral.Init(ippInter);
        }

        if(IPP_RESIZE_PARALLEL && threads > 1)
            parallel_for_(range, *pInvoker, threads*4);
        else
            pInvoker->operator()(range);

        if(!ok)
            return false;
    }
    catch(const ::ipp::IwException &)
    {
        return false;
    }
    return true;
#else
    CV_UNUSED(src_data); CV_UNUSED(src_step); CV_UNUSED(src_width); CV_UNUSED(src_height); CV_UNUSED(dst_data); CV_UNUSED(dst_step);
    CV_UNUSED(dst_width); CV_UNUSED(dst_height); CV_UNUSED(inv_scale_x); CV_UNUSED(inv_scale_y); CV_UNUSED(depth);
    CV_UNUSED(channels); CV_UNUSED(interpolation);
    return false;
#endif
}
#endif

//==================================================================================================

namespace hal {

void resize(int src_type,
            const uchar * src_data, size_t src_step, int src_width, int src_height,
            uchar * dst_data, size_t dst_step, int dst_width, int dst_height,
            double inv_scale_x, double inv_scale_y, int interpolation)
{
    CV_INSTRUMENT_REGION();

    CV_Assert((dst_width > 0 && dst_height > 0) || (inv_scale_x > 0 && inv_scale_y > 0));
    if (inv_scale_x < DBL_EPSILON || inv_scale_y < DBL_EPSILON)
    {
        inv_scale_x = static_cast<double>(dst_width) / src_width;
        inv_scale_y = static_cast<double>(dst_height) / src_height;
    }

    CALL_HAL(resize, cv_hal_resize, src_type, src_data, src_step, src_width, src_height, dst_data, dst_step, dst_width, dst_height, inv_scale_x, inv_scale_y, interpolation);

    int  depth = CV_MAT_DEPTH(src_type), cn = CV_MAT_CN(src_type);
    Size dsize = Size(saturate_cast<int>(src_width*inv_scale_x),
                        saturate_cast<int>(src_height*inv_scale_y));
    CV_Assert( !dsize.empty() );

    CV_IPP_RUN_FAST(ipp_resize(src_data, src_step, src_width, src_height, dst_data, dst_step, dsize.width, dsize.height, inv_scale_x, inv_scale_y, depth, cn, interpolation))

    static ResizeFunc linear_tab[] =
    {
        resizeGeneric_<
            HResizeLinear<uchar, int, short,
                INTER_RESIZE_COEF_SCALE,
                HResizeLinearVec_8u32s>,
            VResizeLinear<uchar, int, short,
                FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
                VResizeLinearVec_32s8u> >,
        0,
        resizeGeneric_<
            HResizeLinear<ushort, float, float, 1,
                HResizeLinearVec_16u32f>,
            VResizeLinear<ushort, float, float, Cast<float, ushort>,
                VResizeLinearVec_32f16u> >,
        resizeGeneric_<
            HResizeLinear<short, float, float, 1,
                HResizeLinearVec_16s32f>,
            VResizeLinear<short, float, float, Cast<float, short>,
                VResizeLinearVec_32f16s> >,
        0,
        resizeGeneric_<
            HResizeLinear<float, float, float, 1,
                HResizeLinearVec_32f>,
            VResizeLinear<float, float, float, Cast<float, float>,
                VResizeLinearVec_32f> >,
        resizeGeneric_<
            HResizeLinear<double, double, float, 1,
                HResizeNoVec>,
            VResizeLinear<double, double, float, Cast<double, double>,
                VResizeNoVec> >,
        0
    };

    static ResizeFunc cubic_tab[] =
    {
        resizeGeneric_<
            HResizeCubic<uchar, int, short>,
            VResizeCubic<uchar, int, short,
                FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
                VResizeCubicVec_32s8u> >,
        0,
        resizeGeneric_<
            HResizeCubic<ushort, float, float>,
            VResizeCubic<ushort, float, float, Cast<float, ushort>,
            VResizeCubicVec_32f16u> >,
        resizeGeneric_<
            HResizeCubic<short, float, float>,
            VResizeCubic<short, float, float, Cast<float, short>,
            VResizeCubicVec_32f16s> >,
        0,
        resizeGeneric_<
            HResizeCubic<float, float, float>,
            VResizeCubic<float, float, float, Cast<float, float>,
            VResizeCubicVec_32f> >,
        resizeGeneric_<
            HResizeCubic<double, double, float>,
            VResizeCubic<double, double, float, Cast<double, double>,
            VResizeNoVec> >,
        0
    };

    static ResizeFunc lanczos4_tab[] =
    {
        resizeGeneric_<HResizeLanczos4<uchar, int, short>,
            VResizeLanczos4<uchar, int, short,
            FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
            VResizeNoVec> >,
        0,
        resizeGeneric_<HResizeLanczos4<ushort, float, float>,
            VResizeLanczos4<ushort, float, float, Cast<float, ushort>,
            VResizeLanczos4Vec_32f16u> >,
        resizeGeneric_<HResizeLanczos4<short, float, float>,
            VResizeLanczos4<short, float, float, Cast<float, short>,
            VResizeLanczos4Vec_32f16s> >,
        0,
        resizeGeneric_<HResizeLanczos4<float, float, float>,
            VResizeLanczos4<float, float, float, Cast<float, float>,
            VResizeLanczos4Vec_32f> >,
        resizeGeneric_<HResizeLanczos4<double, double, float>,
            VResizeLanczos4<double, double, float, Cast<double, double>,
            VResizeNoVec> >,
        0
    };

    static ResizeAreaFastFunc areafast_tab[] =
    {
        resizeAreaFast_<uchar, int, ResizeAreaFastVec<uchar, ResizeAreaFastVec_SIMD_8u> >,
        0,
        resizeAreaFast_<ushort, float, ResizeAreaFastVec<ushort, ResizeAreaFastVec_SIMD_16u> >,
        resizeAreaFast_<short, float, ResizeAreaFastVec<short, ResizeAreaFastVec_SIMD_16s> >,
        0,
        resizeAreaFast_<float, float, ResizeAreaFastVec_SIMD_32f>,
        resizeAreaFast_<double, double, ResizeAreaFastNoVec<double, double> >,
        0
    };

    static ResizeAreaFunc area_tab[] =
    {
        resizeArea_<uchar, float>, 0, resizeArea_<ushort, float>,
        resizeArea_<short, float>, 0, resizeArea_<float, float>,
        resizeArea_<double, double>, 0
    };

    static be_resize_func linear_exact_tab[] =
    {
        resize_bitExact<uchar, interpolationLinear<uchar> >,
        resize_bitExact<schar, interpolationLinear<schar> >,
        resize_bitExact<ushort, interpolationLinear<ushort> >,
        resize_bitExact<short, interpolationLinear<short> >,
        resize_bitExact<int, interpolationLinear<int> >,
        0,
        0,
        0
    };

    double scale_x = 1./inv_scale_x, scale_y = 1./inv_scale_y;

    int iscale_x = saturate_cast<int>(scale_x);
    int iscale_y = saturate_cast<int>(scale_y);

    bool is_area_fast = std::abs(scale_x - iscale_x) < DBL_EPSILON &&
            std::abs(scale_y - iscale_y) < DBL_EPSILON;

    Mat src(Size(src_width, src_height), src_type, const_cast<uchar*>(src_data), src_step);
    Mat dst(dsize, src_type, dst_data, dst_step);

    if (interpolation == INTER_LINEAR_EXACT)
    {
        // in case of inv_scale_x && inv_scale_y is equal to 0.5
        // INTER_AREA (fast) is equal to bit exact INTER_LINEAR
        if (is_area_fast && iscale_x == 2 && iscale_y == 2 && cn != 2)//Area resize implementation for 2-channel images isn't bit-exact
            interpolation = INTER_AREA;
        else
        {
            be_resize_func func = linear_exact_tab[depth];
            CV_Assert(func != 0);
            func(src_data, src_step, src_width, src_height,
                 dst_data, dst_step, dst_width, dst_height,
                 cn, inv_scale_x, inv_scale_y);
            return;
        }
    }

    if( interpolation == INTER_NEAREST )
    {
        resizeNN( src, dst, inv_scale_x, inv_scale_y );
        return;
    }

    if( interpolation == INTER_NEAREST_EXACT )
    {
        resizeNN_bitexact( src, dst, inv_scale_x, inv_scale_y );
        return;
    }

    int k, sx, sy, dx, dy;


    {
        // in case of scale_x && scale_y is equal to 2
        // INTER_AREA (fast) also is equal to INTER_LINEAR
        if( interpolation == INTER_LINEAR && is_area_fast && iscale_x == 2 && iscale_y == 2 )
            interpolation = INTER_AREA;

        // true "area" interpolation is only implemented for the case (scale_x >= 1 && scale_y >= 1).
        // In other cases it is emulated using some variant of bilinear interpolation
        if( interpolation == INTER_AREA && scale_x >= 1 && scale_y >= 1 )
        {
            if( is_area_fast )
            {
                int area = iscale_x*iscale_y;
                size_t srcstep = src_step / src.elemSize1();
                AutoBuffer<int> _ofs(area + dsize.width*cn);
                int* ofs = _ofs.data();
                int* xofs = ofs + area;
                ResizeAreaFastFunc func = areafast_tab[depth];
                CV_Assert( func != 0 );

                for( sy = 0, k = 0; sy < iscale_y; sy++ )
                    for( sx = 0; sx < iscale_x; sx++ )
                        ofs[k++] = (int)(sy*srcstep + sx*cn);

                for( dx = 0; dx < dsize.width; dx++ )
                {
                    int j = dx * cn;
                    sx = iscale_x * j;
                    for( k = 0; k < cn; k++ )
                        xofs[j + k] = sx + k;
                }

                func( src, dst, ofs, xofs, iscale_x, iscale_y );
                return;
            }

            ResizeAreaFunc func = area_tab[depth];
            CV_Assert( func != 0 && cn <= 4 );

            AutoBuffer<DecimateAlpha> _xytab((src_width + src_height)*2);
            DecimateAlpha* xtab = _xytab.data(), *ytab = xtab + src_width*2;

            int xtab_size = computeResizeAreaTab(src_width, dsize.width, cn, scale_x, xtab);
            int ytab_size = computeResizeAreaTab(src_height, dsize.height, 1, scale_y, ytab);

            AutoBuffer<int> _tabofs(dsize.height + 1);
            int* tabofs = _tabofs.data();
            for( k = 0, dy = 0; k < ytab_size; k++ )
            {
                if( k == 0 || ytab[k].di != ytab[k-1].di )
                {
                    assert( ytab[k].di == dy );
                    tabofs[dy++] = k;
                }
            }
            tabofs[dy] = ytab_size;

            func( src, dst, xtab, xtab_size, ytab, ytab_size, tabofs );
            return;
        }
    }

    int xmin = 0, xmax = dsize.width, width = dsize.width*cn;
    bool area_mode = interpolation == INTER_AREA;
    bool fixpt = depth == CV_8U;
    float fx, fy;
    ResizeFunc func=0;
    int ksize=0, ksize2;
    if( interpolation == INTER_CUBIC )
        ksize = 4, func = cubic_tab[depth];
    else if( interpolation == INTER_LANCZOS4 )
        ksize = 8, func = lanczos4_tab[depth];
    else if( interpolation == INTER_LINEAR || interpolation == INTER_AREA )
        ksize = 2, func = linear_tab[depth];
    else
        CV_Error( CV_StsBadArg, "Unknown interpolation method" );
    ksize2 = ksize/2;

    CV_Assert( func != 0 );

    AutoBuffer<uchar> _buffer((width + dsize.height)*(sizeof(int) + sizeof(float)*ksize));
    int* xofs = (int*)_buffer.data();
    int* yofs = xofs + width;
    float* alpha = (float*)(yofs + dsize.height);
    short* ialpha = (short*)alpha;
    float* beta = alpha + width*ksize;
    short* ibeta = ialpha + width*ksize;
    float cbuf[MAX_ESIZE] = {0};

    for( dx = 0; dx < dsize.width; dx++ )
    {
        if( !area_mode )
        {
            fx = (float)((dx+0.5)*scale_x - 0.5);
            sx = cvFloor(fx);
            fx -= sx;
        }
        else
        {
            sx = cvFloor(dx*scale_x);
            fx = (float)((dx+1) - (sx+1)*inv_scale_x);
            fx = fx <= 0 ? 0.f : fx - cvFloor(fx);
        }

        if( sx < ksize2-1 )
        {
            xmin = dx+1;
            if( sx < 0 && (interpolation != INTER_CUBIC && interpolation != INTER_LANCZOS4))
                fx = 0, sx = 0;
        }

        if( sx + ksize2 >= src_width )
        {
            xmax = std::min( xmax, dx );
            if( sx >= src_width-1 && (interpolation != INTER_CUBIC && interpolation != INTER_LANCZOS4))
                fx = 0, sx = src_width-1;
        }

        for( k = 0, sx *= cn; k < cn; k++ )
            xofs[dx*cn + k] = sx + k;

        if( interpolation == INTER_CUBIC )
            interpolateCubic( fx, cbuf );
        else if( interpolation == INTER_LANCZOS4 )
            interpolateLanczos4( fx, cbuf );
        else
        {
            cbuf[0] = 1.f - fx;
            cbuf[1] = fx;
        }
        if( fixpt )
        {
            for( k = 0; k < ksize; k++ )
                ialpha[dx*cn*ksize + k] = saturate_cast<short>(cbuf[k]*INTER_RESIZE_COEF_SCALE);
            for( ; k < cn*ksize; k++ )
                ialpha[dx*cn*ksize + k] = ialpha[dx*cn*ksize + k - ksize];
        }
        else
        {
            for( k = 0; k < ksize; k++ )
                alpha[dx*cn*ksize + k] = cbuf[k];
            for( ; k < cn*ksize; k++ )
                alpha[dx*cn*ksize + k] = alpha[dx*cn*ksize + k - ksize];
        }
    }

    for( dy = 0; dy < dsize.height; dy++ )
    {
        if( !area_mode )
        {
            fy = (float)((dy+0.5)*scale_y - 0.5);
            sy = cvFloor(fy);
            fy -= sy;
        }
        else
        {
            sy = cvFloor(dy*scale_y);
            fy = (float)((dy+1) - (sy+1)*inv_scale_y);
            fy = fy <= 0 ? 0.f : fy - cvFloor(fy);
        }

        yofs[dy] = sy;
        if( interpolation == INTER_CUBIC )
            interpolateCubic( fy, cbuf );
        else if( interpolation == INTER_LANCZOS4 )
            interpolateLanczos4( fy, cbuf );
        else
        {
            cbuf[0] = 1.f - fy;
            cbuf[1] = fy;
        }

        if( fixpt )
        {
            for( k = 0; k < ksize; k++ )
                ibeta[dy*ksize + k] = saturate_cast<short>(cbuf[k]*INTER_RESIZE_COEF_SCALE);
        }
        else
        {
            for( k = 0; k < ksize; k++ )
                beta[dy*ksize + k] = cbuf[k];
        }
    }

    func( src, dst, xofs, fixpt ? (void*)ialpha : (void*)alpha, yofs,
          fixpt ? (void*)ibeta : (void*)beta, xmin, xmax, ksize );
}

} // cv::hal::
} // cv::

//==================================================================================================

void cv::resize( InputArray _src, OutputArray _dst, Size dsize,
                 double inv_scale_x, double inv_scale_y, int interpolation )
{
    CV_INSTRUMENT_REGION();

    Size ssize = _src.size();

    CV_Assert( !ssize.empty() );
    if( dsize.empty() )
    {
        CV_Assert(inv_scale_x > 0); CV_Assert(inv_scale_y > 0);
        dsize = Size(saturate_cast<int>(ssize.width*inv_scale_x),
                     saturate_cast<int>(ssize.height*inv_scale_y));
        CV_Assert( !dsize.empty() );
    }
    else
    {
        inv_scale_x = (double)dsize.width/ssize.width;
        inv_scale_y = (double)dsize.height/ssize.height;
        CV_Assert(inv_scale_x > 0); CV_Assert(inv_scale_y > 0);
    }

    if (interpolation == INTER_LINEAR_EXACT && (_src.depth() == CV_32F || _src.depth() == CV_64F))
        interpolation = INTER_LINEAR; // If depth isn't supported fallback to generic resize

    CV_OCL_RUN(_src.dims() <= 2 && _dst.isUMat() && _src.cols() > 10 && _src.rows() > 10,
               ocl_resize(_src, _dst, dsize, inv_scale_x, inv_scale_y, interpolation))

    // Fake reference to source. Resolves issue 13577 in case of src == dst.
    UMat srcUMat;
    if (_src.isUMat())
        srcUMat = _src.getUMat();

    Mat src = _src.getMat();
    _dst.create(dsize, src.type());
    Mat dst = _dst.getMat();

    if (dsize == ssize)
    {
        // Source and destination are of same size. Use simple copy.
        src.copyTo(dst);
        return;
    }

    hal::resize(src.type(), src.data, src.step, src.cols, src.rows, dst.data, dst.step, dst.cols, dst.rows, inv_scale_x, inv_scale_y, interpolation);
}


CV_IMPL void
cvResize( const CvArr* srcarr, CvArr* dstarr, int method )
{
    cv::Mat src = cv::cvarrToMat(srcarr), dst = cv::cvarrToMat(dstarr);
    CV_Assert( src.type() == dst.type() );
    cv::resize( src, dst, dst.size(), (double)dst.cols/src.cols,
        (double)dst.rows/src.rows, method );
}

/* End of file. */
