#include <iostream>

#include <cmath>

using std::cout;

using std::endl;

inline double bilinear_filter(double x)

{

if (x < 0.0)

x = -x;

if (x < 1.0)

return 1.0 - x;

return 0.0;

}

int precompute_coeffs(int inSize, int outSize, int** boundsp, double** kkp)

{

double filterscale = (double)inSize / outSize;

double scale = filterscale;

if (filterscale < 1.0)

filterscale = 1.0;

double support = 1.0 * filterscale;

int ksize = (int)ceil(support) * 2 + 1;

double* kk = (double*)malloc(outSize * ksize * sizeof(double));

int* bounds = (int*)malloc(outSize * 2* sizeof(int));

double center = 0, ww = 0, ss = 0;

int xmin = 0, xmax = 0;

for (int i = 0; i < outSize; ++i)

{

center = (i + 0.5) * scale;

ww = 0.0;

ss = 1.0 / filterscale;

xmin = (int) (center - support + 0.5);

if (xmin < 0)

xmin = 0;

xmax = (int) (center + support + 0.5);

if (xmax > inSize)

xmax = inSize;

xmax -= xmin;

double* k = &kk[i * ksize];

for (int j = 0; j < xmax; ++j)

{

double w = bilinear_filter((j + xmin - center + 0.5) * ss);

k[j] = w;

ww += w;

}

for (int j = 0; j < xmax; ++j)

{

if (ww != 0.0)

k[j] /= ww;

}

for (int j = xmax; j < ksize; ++j)

k[j] = 0;

bounds[i*2] = xmin;

bounds[i*2 + 1] = xmax;

}

*boundsp = bounds;

*kkp = kk;

return ksize;

}

void resize(const unsigned char* srcImg, unsigned char* dstImg, int srcSize, int dstSize)

{

int srcWidth = srcSize;

int srcHeight = srcSize;

int dstWidth = dstSize;

int dstHeight = dstSize;

int* bounds_horiz = nullptr, *bounds_vert = nullptr;

double* kk_horiz = nullptr, *kk_vert = nullptr;

int ksize_horiz = precompute_coeffs(srcWidth, dstWidth, &bounds_horiz, &kk_horiz);

int ksize_vert = precompute_coeffs(srcHeight, dstHeight, &bounds_vert, &kk_vert);

cout << ksize_horiz << " " << ksize_vert << endl;

int ybox_first = bounds_vert[0];

int ybox_last = bounds_vert[dstHeight*2 - 2] + bounds_vert[dstHeight*2 - 1];

cout << ybox_first << " " << ybox_last << endl;

for (int i = 0; i < dstHeight; ++i)

{

bounds_vert[i*2] -= ybox_first;

}

free(bounds_horiz);

free(bounds_vert);

free(kk_horiz);

free(kk_vert);

}

int main()

{

unsigned char* imgData = new unsigned char[200*200];

unsigned char* resizeImg = new unsigned char[64];

resize(imgData, resizeImg, 200, 64);

delete[] imgData;

delete[] resizeImg;

int k = (64*3+3) & -4;

cout << k << endl;

return 0;

}