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#include <fitz.h>
static void
scalerow(unsigned char *src, int w, int denom, unsigned char *dst, int ncomp)
{
int x, left, n;
int sum[32];
left = 0;
for (n = 0; n < ncomp; n++)
sum[n] = 0;
for (x = 0; x < w; x++)
{
for (n = 0; n < ncomp; n++)
sum[n] += src[x * ncomp + n];
if (++left == denom)
{
left = 0;
for (n = 0; n < ncomp; n++)
{
dst[n] = sum[n] / denom;
sum[n] = 0;
}
dst += ncomp;
}
}
/* left overs */
if (left)
for (n = 0; n < ncomp; n++)
dst[n] = sum[n] / left;
}
static void
scalecols(unsigned char *src, int stride, int w, int denom, unsigned char *dst, int ncomp)
{
int x, y, n;
unsigned char *s;
int sum[32];
for (x = 0; x < w; x++)
{
s = src + (x * ncomp);
for (n = 0; n < ncomp; n++)
sum[n] = 0;
for (y = 0; y < denom; y++)
for (n = 0; n < ncomp; n++)
sum[n] += s[y * stride + n];
for (n = 0; n < ncomp; n++)
dst[n] = sum[n] / denom;
dst += ncomp;
}
}
fz_error *
fz_scalepixmap(fz_pixmap *src, fz_pixmap *dst, int xdenom, int ydenom)
{
assert(src->n == dst->n);
assert(src->a == dst->a);
assert((src->w + xdenom - 1) / xdenom == dst->w);
assert((src->h + ydenom - 1) / ydenom == dst->h);
int ncomp = src->n + src->a;
unsigned char scratch[dst->stride * ydenom];
int y, iy, oy;
for (y = 0, oy = 0; y < (dst->h - 1) * ydenom; y += ydenom, oy++)
{
for (iy = 0; iy < ydenom; iy++)
scalerow(src->samples + (y + iy) * src->stride, src->w, xdenom,
scratch + iy * dst->stride, ncomp);
scalecols(scratch, ncomp * dst->w, dst->w, ydenom,
dst->samples + (oy * dst->stride), ncomp);
}
ydenom = src->h - y;
if (ydenom)
{
for (iy = 0; iy < ydenom; iy++)
scalerow(src->samples + (y + iy) * src->stride, src->w, xdenom,
scratch + iy * (ncomp * dst->w), ncomp);
scalecols(scratch, ncomp * dst->w, dst->w, ydenom,
dst->samples + (oy * dst->stride), ncomp);
}
//printf("unscaled image ");fz_debugpixmap(src);getchar();
//printf("scaled image ");fz_debugpixmap(dst);getchar();
return nil;
}
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