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

   1 /* -*- indent-tabs-mode: nil; tab-width: 4; c-basic-offset: 4; -*-
   2
   3    image.c for the Openbox window manager
   4    Copyright (c) 2006        Mikael Magnusson
   5    Copyright (c) 2003        Ben Jansens
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    See the COPYING file for a copy of the GNU General Public License.
  18 */
  19
  20 #include "geom.h"
  21 #include "image.h"
  22 #include "color.h"
  23
  24 #include <glib.h>
  25
  26 #define FRACTION        12
  27 #define FLOOR(i)        ((i) & (~0UL << FRACTION))
  28 #define AVERAGE(a, b)   (((((a) ^ (b)) & 0xfefefefeL) >> 1) + ((a) & (b)))
  29
  30 static void ImageCopyResampled(RrPixel32 *dst, RrPixel32 *src,
  31                                gulong dstW, gulong dstH,
  32                                gulong srcW, gulong srcH)
  33 {
  34     gulong dstX, dstY, srcX, srcY;
  35     gulong srcX1, srcX2, srcY1, srcY2;
  36     gulong ratioX, ratioY;
  37
  38     ratioX = (srcW << FRACTION) / dstW;
  39     ratioY = (srcH << FRACTION) / dstH;
  40
  41     srcY2 = 0;
  42     for (dstY = 0; dstY < dstH; dstY++) {
  43         srcY1 = srcY2;
  44         srcY2 += ratioY;
  45
  46         srcX2 = 0;
  47         for (dstX = 0; dstX < dstW; dstX++) {
  48             gulong red = 0, green = 0, blue = 0, alpha = 0;
  49             gulong portionX, portionY, portionXY, sumXY = 0;
  50             RrPixel32 pixel;
  51
  52             srcX1 = srcX2;
  53             srcX2 += ratioX;
  54
  55             for (srcY = srcY1; srcY < srcY2; srcY += (1UL << FRACTION)) {
  56                 if (srcY == srcY1) {
  57                     srcY = FLOOR(srcY);
  58                     portionY = (1UL << FRACTION) - (srcY1 - srcY);
  59                     if (portionY > srcY2 - srcY1)
  60                         portionY = srcY2 - srcY1;
  61                 }
  62                 else if (srcY == FLOOR(srcY2))
  63                     portionY = srcY2 - srcY;
  64                 else
  65                     portionY = (1UL << FRACTION);
  66
  67                 for (srcX = srcX1; srcX < srcX2; srcX += (1UL << FRACTION)) {
  68                     if (srcX == srcX1) {
  69                         srcX = FLOOR(srcX);
  70                         portionX = (1UL << FRACTION) - (srcX1 - srcX);
  71                         if (portionX > srcX2 - srcX1)
  72                             portionX = srcX2 - srcX1;
  73                     }
  74                     else if (srcX == FLOOR(srcX2))
  75                         portionX = srcX2 - srcX;
  76                     else
  77                         portionX = (1UL << FRACTION);
  78
  79                     portionXY = (portionX * portionY) >> FRACTION;
  80                     sumXY += portionXY;
  81
  82                     pixel = *(src + (srcY >> FRACTION) * srcW + (srcX >> FRACTION));
  83                     red   += ((pixel >> RrDefaultRedOffset)   & 0xFF) * portionXY;
  84                     green += ((pixel >> RrDefaultGreenOffset) & 0xFF) * portionXY;
  85                     blue  += ((pixel >> RrDefaultBlueOffset)  & 0xFF) * portionXY;
  86                     alpha += ((pixel >> RrDefaultAlphaOffset) & 0xFF) * portionXY;
  87                 }
  88             }
  89
  90             g_assert(sumXY != 0);
  91             red   /= sumXY;
  92             green /= sumXY;
  93             blue  /= sumXY;
  94             alpha /= sumXY;
  95
  96             *dst++ = (red   << RrDefaultRedOffset)   |
  97                      (green << RrDefaultGreenOffset) |
  98                      (blue  << RrDefaultBlueOffset)  |
  99                      (alpha << RrDefaultAlphaOffset);
 100         }
 101     }
 102 }
 103
 104 void RrImageDraw(RrPixel32 *target, RrTextureRGBA *rgba,
 105                  gint target_w, gint target_h,
 106                  RrRect *area)
 107 {
 108     RrPixel32 *dest;
 109     RrPixel32 *source;
 110     gint sw, sh, dw, dh;
 111     gint col, num_pixels;
 112
 113     sw = rgba->width;
 114     sh = rgba->height;
 115
 116     /* keep the ratio */
 117     dw = area->width;
 118     dh = (gint)(dw * ((gdouble)sh / sw));
 119     if (dh > area->height) {
 120         dh = area->height;
 121         dw = (gint)(dh * ((gdouble)sw / sh));
 122     }
 123
 124     if (!(dw && dh))
 125         return; /* XXX sanity check */
 126
 127     if (sw != dw || sh != dh) {
 128         /*if (!(rgba->cache && dw == rgba->cwidth && dh == rgba->cheight))*/ {
 129             g_free(rgba->cache);
 130             rgba->cache = g_new(RrPixel32, dw * dh);
 131             ImageCopyResampled(rgba->cache, rgba->data, dw, dh, sw, sh);
 132             rgba->cwidth = dw;
 133             rgba->cheight = dh;
 134         }
 135         source = rgba->cache;
 136     } else {
 137         source = rgba->data;
 138     }
 139
 140     /* copy source -> dest, and apply the alpha channel */
 141     col = 0;
 142     num_pixels = dw * dh;
 143     dest = target + area->x + target_w * area->y;
 144     while (num_pixels-- > 0) {
 145         guchar alpha, r, g, b, bgr, bgg, bgb;
 146
 147         alpha = *source >> RrDefaultAlphaOffset;
 148         r = *source >> RrDefaultRedOffset;
 149         g = *source >> RrDefaultGreenOffset;
 150         b = *source >> RrDefaultBlueOffset;
 151
 152         /* background color */
 153         bgr = *dest >> RrDefaultRedOffset;
 154         bgg = *dest >> RrDefaultGreenOffset;
 155         bgb = *dest >> RrDefaultBlueOffset;
 156
 157         r = bgr + (((r - bgr) * alpha) >> 8);
 158         g = bgg + (((g - bgg) * alpha) >> 8);
 159         b = bgb + (((b - bgb) * alpha) >> 8);
 160
 161         *dest = ((r << RrDefaultRedOffset) |
 162                  (g << RrDefaultGreenOffset) |
 163                  (b << RrDefaultBlueOffset));
 164
 165         dest++;
 166         source++;
 167
 168         if (++col >= dw) {
 169             col = 0;
 170             dest += target_w - dw;
 171         }
 172     }
 173 }