Dogcows Code - chaz/openbox/blob - render/image.c

   1 #include <glib.h>
   2 #include "../kernel/geom.h"
   3 #include "image.h"
   4
   5 void image_draw(pixel32 *target, TextureRGBA *rgba, Rect *position,
   6                 Rect *surarea)
   7 {
   8   unsigned long *draw = rgba->data;
   9   int c, sfw, sfh;
  10   unsigned int i, e;
  11   sfw = position->width;
  12   sfh = position->height;
  13
  14   /* it would be nice if this worked, but this function is well broken in these
  15      cercumstances. */
  16   g_assert(position->width == surarea->width &&
  17            position->height == surarea->height);
  18
  19   g_assert(rgba->data != NULL);
  20
  21   if ((rgba->width != sfw || rgba->height != sfh) &&
  22       (rgba->width != rgba->cwidth || rgba->height != rgba->cheight)) {
  23     double dx = rgba->width / (double)sfw;
  24     double dy = rgba->height / (double)sfh;
  25     double px = 0.0;
  26     double py = 0.0;
  27     int iy = 0;
  28
  29     /* scale it and cache it */
  30     if (rgba->cache != NULL)
  31         g_free(rgba->cache);
  32     rgba->cache = g_new(unsigned long, sfw * sfh);
  33     rgba->cwidth = sfw;
  34     rgba->cheight = sfh;
  35     for (i = 0, c = 0, e = sfw*sfh; i < e; ++i) {
  36       rgba->cache[i] = rgba->data[(int)px + iy];
  37       if (++c >= sfw) {
  38         c = 0;
  39         px = 0;
  40         py += dy;
  41         iy = (int)py * rgba->width;
  42       } else
  43         px += dx;
  44     }
  45
  46 /* do we use the cache we may have just created, or the original? */
  47     if (rgba->width != sfw || rgba->height != sfh)
  48         draw = rgba->cache;
  49
  50     /* apply the alpha channel */
  51     for (i = 0, c = 0, e = sfw*sfh; i < e; ++i) {
  52       unsigned char alpha = draw[i] >> 24;
  53       unsigned char r = draw[i] >> 16;
  54       unsigned char g = draw[i] >> 8;
  55       unsigned char b = draw[i];
  56
  57       /* background color */
  58       unsigned char bgr = target[i] >> default_red_shift;
  59       unsigned char bgg = target[i] >> default_green_shift;
  60       unsigned char bgb = target[i] >> default_blue_shift;
  61
  62       r = bgr + (((r - bgr) * alpha) >> 8);
  63       g = bgg + (((g - bgg) * alpha) >> 8);
  64       b = bgb + (((b - bgb) * alpha) >> 8);
  65
  66       target[i] = (r << default_red_shift) | (g << default_green_shift) |
  67         (b << default_blue_shift);
  68     }
  69   }
  70 }