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      1 /*
      2  * Copyright (C) 2003, 2004, 2005, 2006, 2010 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef Color_h
     27 #define Color_h
     28 
     29 #include "core/platform/animation/AnimationUtilities.h"
     30 #include "wtf/FastAllocBase.h"
     31 #include "wtf/Forward.h"
     32 #include "wtf/unicode/Unicode.h"
     33 
     34 namespace WebCore {
     35 
     36 class Color;
     37 
     38 typedef unsigned RGBA32;        // RGBA quadruplet
     39 
     40 RGBA32 makeRGB(int r, int g, int b);
     41 RGBA32 makeRGBA(int r, int g, int b, int a);
     42 
     43 RGBA32 colorWithOverrideAlpha(RGBA32 color, float overrideAlpha);
     44 RGBA32 makeRGBA32FromFloats(float r, float g, float b, float a);
     45 RGBA32 makeRGBAFromHSLA(double h, double s, double l, double a);
     46 RGBA32 makeRGBAFromCMYKA(float c, float m, float y, float k, float a);
     47 
     48 int differenceSquared(const Color&, const Color&);
     49 
     50 inline int redChannel(RGBA32 color) { return (color >> 16) & 0xFF; }
     51 inline int greenChannel(RGBA32 color) { return (color >> 8) & 0xFF; }
     52 inline int blueChannel(RGBA32 color) { return color & 0xFF; }
     53 inline int alphaChannel(RGBA32 color) { return (color >> 24) & 0xFF; }
     54 
     55 class Color {
     56     WTF_MAKE_FAST_ALLOCATED;
     57 public:
     58     Color() : m_color(0) { }
     59     Color(RGBA32 color) : m_color(color) { }
     60     Color(int r, int g, int b) : m_color(makeRGB(r, g, b)) { }
     61     Color(int r, int g, int b, int a) : m_color(makeRGBA(r, g, b, a)) { }
     62     // Color is currently limited to 32bit RGBA, perhaps some day we'll support better colors
     63     Color(float r, float g, float b, float a) : m_color(makeRGBA32FromFloats(r, g, b, a)) { }
     64     // Creates a new color from the specific CMYK and alpha values.
     65     Color(float c, float m, float y, float k, float a) : m_color(makeRGBAFromCMYKA(c, m, y, k, a)) { }
     66 
     67     static Color createUnchecked(int r, int g, int b)
     68     {
     69         RGBA32 color = 0xFF000000 | r << 16 | g << 8 | b;
     70         return Color(color);
     71     }
     72     static Color createUnchecked(int r, int g, int b, int a)
     73     {
     74         RGBA32 color = a << 24 | r << 16 | g << 8 | b;
     75         return Color(color);
     76     }
     77 
     78     // Returns the color serialized according to HTML5
     79     // - http://www.whatwg.org/specs/web-apps/current-work/#serialization-of-a-color
     80     String serialized() const;
     81 
     82     // Returns the color serialized as either #RRGGBB or #RRGGBBAA
     83     // The latter format is not a valid CSS color, and should only be seen in DRT dumps.
     84     String nameForRenderTreeAsText() const;
     85 
     86     bool hasAlpha() const { return alpha() < 255; }
     87 
     88     int red() const { return redChannel(m_color); }
     89     int green() const { return greenChannel(m_color); }
     90     int blue() const { return blueChannel(m_color); }
     91     int alpha() const { return alphaChannel(m_color); }
     92 
     93     RGBA32 rgb() const { return m_color; } // Preserve the alpha.
     94     void setRGB(int r, int g, int b) { m_color = makeRGB(r, g, b); }
     95     void setRGB(RGBA32 rgb) { m_color = rgb; }
     96     void getRGBA(float& r, float& g, float& b, float& a) const;
     97     void getRGBA(double& r, double& g, double& b, double& a) const;
     98     void getHSL(double& h, double& s, double& l) const;
     99 
    100     Color light() const;
    101     Color dark() const;
    102 
    103     // This is an implementation of Porter-Duff's "source-over" equation
    104     Color blend(const Color&) const;
    105     Color blendWithWhite() const;
    106 
    107     static bool parseHexColor(const String&, RGBA32&);
    108     static bool parseHexColor(const LChar*, unsigned, RGBA32&);
    109     static bool parseHexColor(const UChar*, unsigned, RGBA32&);
    110 
    111     static const RGBA32 black = 0xFF000000;
    112     static const RGBA32 white = 0xFFFFFFFF;
    113     static const RGBA32 darkGray = 0xFF808080;
    114     static const RGBA32 gray = 0xFFA0A0A0;
    115     static const RGBA32 lightGray = 0xFFC0C0C0;
    116     static const RGBA32 transparent = 0x00000000;
    117     static const RGBA32 stdShadowColor = 0x00000055;
    118 
    119 private:
    120     RGBA32 m_color;
    121 };
    122 
    123 inline bool operator==(const Color& a, const Color& b)
    124 {
    125     return a.rgb() == b.rgb();
    126 }
    127 
    128 inline bool operator!=(const Color& a, const Color& b)
    129 {
    130     return !(a == b);
    131 }
    132 
    133 Color colorFromPremultipliedARGB(RGBA32);
    134 RGBA32 premultipliedARGBFromColor(const Color&);
    135 
    136 inline Color blend(const Color& from, const Color& to, double progress, bool blendPremultiplied = true)
    137 {
    138     if (blendPremultiplied) {
    139         // Contrary to the name, RGBA32 actually stores ARGB, so we can initialize Color directly from premultipliedARGBFromColor().
    140         // Also, premultipliedARGBFromColor() bails on zero alpha, so special-case that.
    141         Color premultFrom = from.alpha() ? premultipliedARGBFromColor(from) : 0;
    142         Color premultTo = to.alpha() ? premultipliedARGBFromColor(to) : 0;
    143 
    144         Color premultBlended(blend(premultFrom.red(), premultTo.red(), progress),
    145                      blend(premultFrom.green(), premultTo.green(), progress),
    146                      blend(premultFrom.blue(), premultTo.blue(), progress),
    147                      blend(premultFrom.alpha(), premultTo.alpha(), progress));
    148 
    149         return Color(colorFromPremultipliedARGB(premultBlended.rgb()));
    150     }
    151 
    152     return Color(blend(from.red(), to.red(), progress),
    153                  blend(from.green(), to.green(), progress),
    154                  blend(from.blue(), to.blue(), progress),
    155                  blend(from.alpha(), to.alpha(), progress));
    156 }
    157 } // namespace WebCore
    158 
    159 #endif // Color_h
    160