khtml/svg/ColorDistance.cpp

   1 /*
   2  Copyright (C) 2007 Eric Seidel <eric@webkit.org>
   3
   4  This file is part of the WebKit project
   5
   6  This library is free software; you can redistribute it and/or
   7  modify it under the terms of the GNU Library General Public
   8  License as published by the Free Software Foundation; either
   9  version 2 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  Library General Public License for more details.
  15
  16  You should have received a copy of the GNU Library General Public License
  17  along with this library; see the file COPYING.LIB.  If not, write to
  18  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  Boston, MA 02110-1301, USA.
  20  */
  21
  22 #include "config.h"
  23 #if ENABLE(SVG)
  24 #include "ColorDistance.h"
  25 #include "Color.h"
  26 #include <wtf/MathExtras.h>
  27
  28 namespace WebCore {
  29
  30 ColorDistance::ColorDistance()
  31     : m_redDiff(0)
  32     , m_greenDiff(0)
  33     , m_blueDiff(0)
  34 {
  35 }
  36
  37 ColorDistance::ColorDistance(const Color& fromColor, const Color& toColor)
  38     : m_redDiff(toColor.red() - fromColor.red())
  39     , m_greenDiff(toColor.green() - fromColor.green())
  40     , m_blueDiff(toColor.blue() - fromColor.blue())
  41 {
  42 }
  43
  44 ColorDistance::ColorDistance(int redDiff, int greenDiff, int blueDiff)
  45     : m_redDiff(redDiff)
  46     , m_greenDiff(greenDiff)
  47     , m_blueDiff(blueDiff)
  48 {
  49 }
  50
  51 static inline int clampColorValue(int v)
  52 {
  53     if (v > 255)
  54         v = 255;
  55     else if (v < 0)
  56         v = 0;
  57     return v;
  58 }
  59
  60 ColorDistance ColorDistance::scaledDistance(float scaleFactor) const
  61 {
  62     return ColorDistance(static_cast<int>(scaleFactor * m_redDiff),
  63                          static_cast<int>(scaleFactor * m_greenDiff),
  64                          static_cast<int>(scaleFactor * m_blueDiff));
  65 }
  66
  67 Color ColorDistance::addColorsAndClamp(const Color& first, const Color& second)
  68 {
  69     return Color(clampColorValue(first.red() + second.red()),
  70                  clampColorValue(first.green() + second.green()),
  71                  clampColorValue(first.blue() + second.blue()));
  72 }
  73
  74 Color ColorDistance::addToColorAndClamp(const Color& color) const
  75 {
  76     return Color(clampColorValue(color.red() + m_redDiff),
  77                  clampColorValue(color.green() + m_greenDiff),
  78                  clampColorValue(color.blue() + m_blueDiff));
  79 }
  80
  81 bool ColorDistance::isZero() const
  82 {
  83     return (m_redDiff == 0 && m_blueDiff == 0 && m_greenDiff == 0);
  84 }
  85
  86 float ColorDistance::distance() const
  87 {
  88     // This is just a simple distance calculation, not respecting color spaces
  89     return sqrtf(m_redDiff * m_redDiff + m_blueDiff * m_blueDiff + m_greenDiff * m_greenDiff);
  90 }
  91
  92 }
  93
  94 #endif