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) 2003-2007   Dana 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
  83                             + (srcX >> FRACTION));
  84                     red   += ((pixel >> RrDefaultRedOffset)   & 0xFF)
  85                              * portionXY;
  86                     green += ((pixel >> RrDefaultGreenOffset) & 0xFF)
  87                              * portionXY;
  88                     blue  += ((pixel >> RrDefaultBlueOffset)  & 0xFF)
  89                              * portionXY;
  90                     alpha += ((pixel >> RrDefaultAlphaOffset) & 0xFF)
  91                              * portionXY;
  92                 }
  93             }
  94
  95             g_assert(sumXY != 0);
  96             red   /= sumXY;
  97             green /= sumXY;
  98             blue  /= sumXY;
  99             alpha /= sumXY;
 100
 101             *dst++ = (red   << RrDefaultRedOffset)   |
 102                      (green << RrDefaultGreenOffset) |
 103                      (blue  << RrDefaultBlueOffset)  |
 104                      (alpha << RrDefaultAlphaOffset);
 105         }
 106     }
 107 }
 108
 109 void RrImageDraw(RrPixel32 *target, RrTextureRGBA *rgba,
 110                  gint target_w, gint target_h,
 111                  RrRect *area)
 112 {
 113     RrPixel32 *dest;
 114     RrPixel32 *source;
 115     gint sw, sh, dw, dh;
 116     gint col, num_pixels;
 117
 118     sw = rgba->width;
 119     sh = rgba->height;
 120
 121     /* keep the ratio */
 122     dw = area->width;
 123     dh = (gint)(dw * ((gdouble)sh / sw));
 124     if (dh > area->height) {
 125         dh = area->height;
 126         dw = (gint)(dh * ((gdouble)sw / sh));
 127     }
 128
 129     if (!(dw && dh))
 130         return; /* XXX sanity check */
 131
 132     if (sw != dw || sh != dh) {
 133         /*if (!(rgba->cache && dw == rgba->cwidth && dh == rgba->cheight))*/ {
 134             g_free(rgba->cache);
 135             rgba->cache = g_new(RrPixel32, dw * dh);
 136             ImageCopyResampled(rgba->cache, rgba->data, dw, dh, sw, sh);
 137             rgba->cwidth = dw;
 138             rgba->cheight = dh;
 139         }
 140         source = rgba->cache;
 141     } else {
 142         source = rgba->data;
 143     }
 144
 145     /* copy source -> dest, and apply the alpha channel */
 146     col = 0;
 147     num_pixels = dw * dh;
 148     dest = target + area->x + target_w * area->y;
 149     while (num_pixels-- > 0) {
 150         guchar alpha, r, g, b, bgr, bgg, bgb;
 151
 152         alpha = *source >> RrDefaultAlphaOffset;
 153         r = *source >> RrDefaultRedOffset;
 154         g = *source >> RrDefaultGreenOffset;
 155         b = *source >> RrDefaultBlueOffset;
 156
 157         /* background color */
 158         bgr = *dest >> RrDefaultRedOffset;
 159         bgg = *dest >> RrDefaultGreenOffset;
 160         bgb = *dest >> RrDefaultBlueOffset;
 161
 162         r = bgr + (((r - bgr) * alpha) >> 8);
 163         g = bgg + (((g - bgg) * alpha) >> 8);
 164         b = bgb + (((b - bgb) * alpha) >> 8);
 165
 166         *dest = ((r << RrDefaultRedOffset) |
 167                  (g << RrDefaultGreenOffset) |
 168                  (b << RrDefaultBlueOffset));
 169
 170         dest++;
 171         source++;
 172
 173         if (++col >= dw) {
 174             col = 0;
 175             dest += target_w - dw;
 176         }
 177     }
 178 }