libswfdec/swfdec_color.c

   1 /* Swfdec
   2  * Copyright (C) 2003-2006 David Schleef <ds@schleef.org>
   3  *               2005-2006 Eric Anholt <eric@anholt.net>
   4  *                    2006 Benjamin Otte <otte@gnome.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  * Boston, MA  02110-1301  USA
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <math.h>
  27 #include "swfdec_color.h"
  28 #include "swfdec_debug.h"
  29
  30 SwfdecColor
  31 swfdec_color_apply_morph (SwfdecColor start, SwfdecColor end, unsigned int ratio)
  32 {
  33   unsigned int r, g, b, a;
  34   unsigned int start_ratio, end_ratio;
  35
  36   g_assert (ratio < 65536);
  37   if (ratio == 0)
  38     return start;
  39   if (ratio == 65535)
  40     return end;
  41   start_ratio = 65535 - ratio;
  42   end_ratio = ratio;
  43   r = (SWF_COLOR_R (start) * start_ratio + SWF_COLOR_R (end) * end_ratio) / 65535;
  44   g = (SWF_COLOR_G (start) * start_ratio + SWF_COLOR_G (end) * end_ratio) / 65535;
  45   b = (SWF_COLOR_B (start) * start_ratio + SWF_COLOR_B (end) * end_ratio) / 65535;
  46   a = (SWF_COLOR_A (start) * start_ratio + SWF_COLOR_A (end) * end_ratio) / 65535;
  47
  48   return SWF_COLOR_COMBINE (r, g, b, a);
  49 }
  50
  51 void
  52 swfdec_color_set_source (cairo_t *cr, SwfdecColor color)
  53 {
  54   cairo_set_source_rgba (cr,
  55       SWF_COLOR_R (color) / 255.0, SWF_COLOR_G (color) / 255.0,
  56       SWF_COLOR_B (color) / 255.0, SWF_COLOR_A (color) / 255.0);
  57 }
  58
  59 unsigned int
  60 swfdec_color_apply_transform (unsigned int in, const SwfdecColorTransform * trans)
  61 {
  62   int r, g, b, a;
  63
  64   r = SWF_COLOR_R (in);
  65   g = SWF_COLOR_G (in);
  66   b = SWF_COLOR_B (in);
  67   a = SWF_COLOR_A (in);
  68
  69   SWFDEC_LOG ("in rgba %d,%d,%d,%d", r, g, b, a);
  70
  71   r = (r * trans->ra >> 8) + trans->rb;
  72   g = (g * trans->ga >> 8) + trans->gb;
  73   b = (b * trans->ba >> 8) + trans->bb;
  74   a = (a * trans->aa >> 8) + trans->ab;
  75
  76   r = CLAMP (r, 0, 255);
  77   g = CLAMP (g, 0, 255);
  78   b = CLAMP (b, 0, 255);
  79   a = CLAMP (a, 0, 255);
  80
  81   SWFDEC_LOG ("out rgba %d,%d,%d,%d", r, g, b, a);
  82
  83   return SWF_COLOR_COMBINE (r, g, b, a);
  84 }
  85
  86 /**
  87  * swfdec_color_transform_init_identity:
  88  * @trans: a #SwfdecColorTransform
  89  *
  90  * Initializes the color transform so it doesn't transform any colors.
  91  **/
  92 void
  93 swfdec_color_transform_init_identity (SwfdecColorTransform * trans)
  94 {
  95   g_return_if_fail (trans != NULL);
  96
  97   trans->ra = 256;
  98   trans->ga = 256;
  99   trans->ba = 256;
 100   trans->aa = 256;
 101   trans->rb = 0;
 102   trans->gb = 0;
 103   trans->bb = 0;
 104   trans->ab = 0;
 105 }
 106
 107 /**
 108  * swfdec_color_transform_init_color:
 109  * @trans: a #SwfdecColorTransform
 110  * @color: a #SwfdecColor to transform to
 111  *
 112  * Initializes this color transform so it results in exactly @color no matter
 113  * the input.
 114  **/
 115 void
 116 swfdec_color_transform_init_color (SwfdecColorTransform *trans, SwfdecColor color)
 117 {
 118   trans->ra = 0;
 119   trans->rb = SWF_COLOR_R (color);
 120   trans->ga = 0;
 121   trans->gb = SWF_COLOR_G (color);
 122   trans->ba = 0;
 123   trans->bb = SWF_COLOR_B (color);
 124   trans->aa = 0;
 125   trans->ab = SWF_COLOR_A (color);
 126 }
 127
 128 /**
 129  * swfdec_color_transform_chain:
 130  * @dest: #SwfdecColorTransform to take the result
 131  * @last: a #SwfdecColorTransform
 132  * @first: a #SwfdecColorTransform
 133  *
 134  * Computes a color transform that has the same effect as if the color
 135  * transforms @first and @last would have been applied one after another.
 136  **/
 137 void
 138 swfdec_color_transform_chain (SwfdecColorTransform *dest,
 139     const SwfdecColorTransform *last, const SwfdecColorTransform *first)
 140 {
 141   g_return_if_fail (dest != NULL);
 142   g_return_if_fail (last != NULL);
 143   g_return_if_fail (first != NULL);
 144
 145   /* FIXME: CLAMP here? */
 146   dest->ra = last->ra * first->ra >> 8;
 147   dest->rb = (last->ra * first->rb >> 8) + last->rb;
 148   dest->ga = last->ga * first->ga >> 8;
 149   dest->gb = (last->ga * first->gb >> 8) + last->gb;
 150   dest->ba = last->ba * first->ba >> 8;
 151   dest->bb = (last->ba * first->bb >> 8) + last->bb;
 152   dest->aa = last->aa * first->aa >> 8;
 153   dest->ab = (last->aa * first->ab >> 8) + last->ab;
 154 }
 155