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