WebCore/svg/ColorDistance.cpp

   1 /*
   2  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public License
  15  * along with this library; see the file COPYING.LIB.  If not, write to
  16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  */
  19
  20 #include "config.h"
  21 #if ENABLE(SVG)
  22 #include "ColorDistance.h"
  23 #include "Color.h"
  24 #include <wtf/MathExtras.h>
  25
  26 namespace WebCore {
  27
  28 ColorDistance::ColorDistance()
  29     : m_redDiff(0)
  30     , m_greenDiff(0)
  31     , m_blueDiff(0)
  32 {
  33 }
  34
  35 ColorDistance::ColorDistance(const Color& fromColor, const Color& toColor)
  36     : m_redDiff(toColor.red() - fromColor.red())
  37     , m_greenDiff(toColor.green() - fromColor.green())
  38     , m_blueDiff(toColor.blue() - fromColor.blue())
  39 {
  40 }
  41
  42 ColorDistance::ColorDistance(int redDiff, int greenDiff, int blueDiff)
  43     : m_redDiff(redDiff)
  44     , m_greenDiff(greenDiff)
  45     , m_blueDiff(blueDiff)
  46 {
  47 }
  48
  49 static inline int clampColorValue(int v)
  50 {
  51     if (v > 255)
  52         v = 255;
  53     else if (v < 0)
  54         v = 0;
  55     return v;
  56 }
  57
  58 ColorDistance ColorDistance::scaledDistance(float scaleFactor) const
  59 {
  60     return ColorDistance(static_cast<int>(scaleFactor * m_redDiff),
  61                          static_cast<int>(scaleFactor * m_greenDiff),
  62                          static_cast<int>(scaleFactor * m_blueDiff));
  63 }
  64
  65 Color ColorDistance::addColorsAndClamp(const Color& first, const Color& second)
  66 {
  67     return Color(clampColorValue(first.red() + second.red()),
  68                  clampColorValue(first.green() + second.green()),
  69                  clampColorValue(first.blue() + second.blue()));
  70 }
  71
  72 Color ColorDistance::addToColorAndClamp(const Color& color) const
  73 {
  74     return Color(clampColorValue(color.red() + m_redDiff),
  75                  clampColorValue(color.green() + m_greenDiff),
  76                  clampColorValue(color.blue() + m_blueDiff));
  77 }
  78
  79 bool ColorDistance::isZero() const
  80 {
  81     return (m_redDiff == 0 && m_blueDiff == 0 && m_greenDiff == 0);
  82 }
  83
  84 float ColorDistance::distance() const
  85 {
  86     // This is just a simple distance calculation, not respecting color spaces
  87     return sqrtf(m_redDiff * m_redDiff + m_blueDiff * m_blueDiff + m_greenDiff * m_greenDiff);
  88 }
  89
  90 }
  91
  92 #endif