diff options
Diffstat (limited to 'raster/imagescale.c')
| -rw-r--r-- | raster/imagescale.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/raster/imagescale.c b/raster/imagescale.c new file mode 100644 index 00000000..ede19f1c --- /dev/null +++ b/raster/imagescale.c @@ -0,0 +1,191 @@ +#include <fitz.h> + +typedef unsigned char byte; + +static void srown(byte *src, byte *dst, int w, int denom, int n) +{ + int x, left, k; + int sum[FZ_MAXCOLORS]; + + left = 0; + for (k = 0; k < n; k++) + sum[k] = 0; + + for (x = 0; x < w; x++) + { + for (k = 0; k < n; k++) + sum[k] += src[x * n + k]; + if (++left == denom) + { + left = 0; + for (k = 0; k < n; k++) + { + dst[k] = sum[k] / denom; + sum[k] = 0; + } + dst += n; + } + } + + /* left overs */ + if (left) + for (k = 0; k < n; k++) + dst[k] = sum[k] / left; +} + +static void srow1(byte *src, byte *dst, int w, int denom) +{ + srown(src, dst, w, denom, 1); +} + +static void srow2(byte *src, byte *dst, int w, int denom) +{ + srown(src, dst, w, denom, 2); +} + +static void srow4(byte *src, byte *dst, int w, int denom) +{ + srown(src, dst, w, denom, 4); +} + +static void srow5(byte *src, byte *dst, int w, int denom) +{ + srown(src, dst, w, denom, 5); +} + +static void scoln(byte *src, byte *dst, int w, int denom, int n) +{ + int x, y, k; + byte *s; + int sum[FZ_MAXCOLORS]; + + for (x = 0; x < w; x++) + { + s = src + (x * n); + for (k = 0; k < n; k++) + sum[k] = 0; + for (y = 0; y < denom; y++) + for (k = 0; k < n; k++) + sum[k] += s[y * w * n + k]; + for (k = 0; k < n; k++) + dst[k] = sum[k] / denom; + dst += n; + } +} + +static void scol1(byte *src, byte *dst, int w, int denom) +{ + scoln(src, dst, w, denom, 1); +} + +static void scol2(byte *src, byte *dst, int w, int denom) +{ + scoln(src, dst, w, denom, 2); +} + +static void scol4(byte *src, byte *dst, int w, int denom) +{ + scoln(src, dst, w, denom, 4); +} + +static void scol5(byte *src, byte *dst, int w, int denom) +{ + scoln(src, dst, w, denom, 5); +} + +void (*fz_srown)(byte *src, byte *dst, int w, int denom, int n) = srown; +void (*fz_srow1)(byte *src, byte *dst, int w, int denom) = srow1; +void (*fz_srow2)(byte *src, byte *dst, int w, int denom) = srow2; +void (*fz_srow4)(byte *src, byte *dst, int w, int denom) = srow4; +void (*fz_srow5)(byte *src, byte *dst, int w, int denom) = srow5; + +void (*fz_scoln)(byte *src, byte *dst, int w, int denom, int n) = scoln; +void (*fz_scol1)(byte *src, byte *dst, int w, int denom) = scol1; +void (*fz_scol2)(byte *src, byte *dst, int w, int denom) = scol2; +void (*fz_scol4)(byte *src, byte *dst, int w, int denom) = scol4; +void (*fz_scol5)(byte *src, byte *dst, int w, int denom) = scol5; + +fz_error * +fz_scalepixmap(fz_pixmap **dstp, fz_pixmap *src, int xdenom, int ydenom) +{ + fz_error *error; + fz_pixmap *dst; + unsigned char *buf; + int y, iy, oy; + int ow, oh, n; + + void (*srowx)(byte *src, byte *dst, int w, int denom) = nil; + void (*scolx)(byte *src, byte *dst, int w, int denom) = nil; + + ow = (src->w + xdenom - 1) / xdenom; + oh = (src->h + ydenom - 1) / ydenom; + n = src->n; + + buf = fz_malloc(ow * n * ydenom); + if (!buf) + return fz_outofmem; + + error = fz_newpixmap(&dst, 0, 0, ow, oh, src->n); + if (error) + { + fz_free(buf); + return error; + } + + switch (n) + { + case 1: srowx = fz_srow1; scolx = fz_scol1; break; + case 2: srowx = fz_srow2; scolx = fz_scol2; break; + case 4: srowx = fz_srow4; scolx = fz_scol4; break; + case 5: srowx = fz_srow5; scolx = fz_scol5; break; + } + + if (srowx && scolx) + { + for (y = 0, oy = 0; y < (src->h / ydenom) * ydenom; y += ydenom, oy++) + { + for (iy = 0; iy < ydenom; iy++) + srowx(src->samples + (y + iy) * src->w * n, + buf + iy * ow * n, + src->w, xdenom); + scolx(buf, dst->samples + oy * dst->w * n, dst->w, ydenom); + } + + ydenom = src->h - y; + if (ydenom) + { + for (iy = 0; iy < ydenom; iy++) + srowx(src->samples + (y + iy) * src->w * n, + buf + iy * ow * n, + src->w, xdenom); + scolx(buf, dst->samples + oy * dst->w * n, dst->w, ydenom); + } + } + + else + { + for (y = 0, oy = 0; y < (src->h / ydenom) * ydenom; y += ydenom, oy++) + { + for (iy = 0; iy < ydenom; iy++) + fz_srown(src->samples + (y + iy) * src->w * n, + buf + iy * ow * n, + src->w, xdenom, n); + fz_scoln(buf, dst->samples + oy * dst->w * n, dst->w, ydenom, n); + } + + ydenom = src->h - y; + if (ydenom) + { + for (iy = 0; iy < ydenom; iy++) + fz_srown(src->samples + (y + iy) * src->w * n, + buf + iy * ow * n, + src->w, xdenom, n); + fz_scoln(buf, dst->samples + oy * dst->w * n, dst->w, ydenom, n); + } + } + + fz_free(buf); + *dstp = dst; + return nil; +} + |