text: /*
   * Copyright (C) 2003, 2004, 2005, 2006, 2010 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_COLOR_H_
  #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_COLOR_H_
  
  #include "third_party/blink/renderer/platform/platform_export.h"
  #include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
  #include "third_party/blink/renderer/platform/wtf/forward.h"
  #include "third_party/blink/renderer/platform/wtf/text/unicode.h"
  
  namespace blink {
  
  class Color;
  
  typedef unsigned RGBA32;  // RGBA quadruplet
  
  PLATFORM_EXPORT RGBA32 MakeRGB(int r, int g, int b);
  PLATFORM_EXPORT RGBA32 MakeRGBA(int r, int g, int b, int a);
  
  PLATFORM_EXPORT RGBA32 MakeRGBA32FromFloats(float r, float g, float b, float a);
  PLATFORM_EXPORT RGBA32 MakeRGBAFromHSLA(double h, double s, double l, double a);
  PLATFORM_EXPORT RGBA32
  MakeRGBAFromCMYKA(float c, float m, float y, float k, float a);
  
  PLATFORM_EXPORT int DifferenceSquared(const Color&, const Color&);
  
  inline int RedChannel(RGBA32 color) {
    return (color >> 16) & 0xFF;
  }
  inline int GreenChannel(RGBA32 color) {
    return (color >> 8) & 0xFF;
  }
  inline int BlueChannel(RGBA32 color) {
    return color & 0xFF;
  }
  inline int AlphaChannel(RGBA32 color) {
    return (color >> 24) & 0xFF;
  }
  
  struct NamedColor {
    DISALLOW_NEW();
    const char* name;
    unsigned argb_value;
  };
  
  PLATFORM_EXPORT const NamedColor* FindColor(const char* str, unsigned len);
  
  class PLATFORM_EXPORT Color {
    DISALLOW_NEW();
  
   public:
    constexpr Color() : color_(Color::kTransparent) {}
    constexpr Color(RGBA32 color) : color_(color) {}
    Color(int r, int g, int b) : color_(MakeRGB(r, g, b)) {}
    Color(int r, int g, int b, int a) : color_(MakeRGBA(r, g, b, a)) {}
    // Color is currently limited to 32bit RGBA. Perhaps some day we'll support
    // better colors.
    Color(float r, float g, float b, float a)
        : color_(MakeRGBA32FromFloats(r, g, b, a)) {}
    // Creates a new color from the specific CMYK and alpha values.
    Color(float c, float m, float y, float k, float a)
        : color_(MakeRGBAFromCMYKA(c, m, y, k, a)) {}
  
    static constexpr Color CreateUnchecked(int r, int g, int b) {
      RGBA32 color = 0xFF000000 | r << 16 | g << 8 | b;
      return Color(color);
    }
    static constexpr Color CreateUnchecked(int r, int g, int b, int a) {
      RGBA32 color = a << 24 | r << 16 | g << 8 | b;
      return Color(color);
    }
  
    // Returns the color serialized according to HTML5:
    // http://www.whatwg.org/specs/web-apps/current-work/#serialization-of-a-color
    String Serialized() const;
  
    // Returns the color serialized as either #RRGGBB or #RRGGBBAA. The latter
    // format is not a valid CSS color, and should only be seen in DRT dumps.
    String NameForLayoutTreeAsText() const;
  
    // Returns whether parsing succeeded. The resulting Color is arbitrary
    // if parsing fails.
    bool SetFromString(const String&);
    bool SetNamedColor(const String&);
  
    bool HasAlpha() const { return Alpha() < 255; }
  
    int Red() const { return RedChannel(color_); }
    int Green() const { return GreenChannel(color_); }
    int Blue() const { return BlueChannel(color_); }
    int Alpha() const { return AlphaChannel(color_); }
  
    RGBA32 Rgb() const { return color_; }  // Preserve the alpha.
    void SetRGB(int r, int g, int b) { color_ = MakeRGB(r, g, b); }
    void SetRGB(RGBA32 rgb) { color_ = rgb; }
    void GetRGBA(float& r, float& g, float& b, float& a) const;
    void GetRGBA(double& r, double& g, double& b, double& a) const;
    void GetHSL(double& h, double& s, double& l) const;
  
    Color Light() const;
    Color Dark() const;
  
    Color CombineWithAlpha(float other_alpha) const;
  
    // This is an implementation of Porter-Duff's "source-over" equation
    Color Blend(const Color&) const;
    Color BlendWithWhite() const;
  
    static bool ParseHexColor(const StringView&, RGBA32&);
    static bool ParseHexColor(const LChar*, unsigned, RGBA32&);
    static bool ParseHexColor(const UChar*, unsigned, RGBA32&);
  
    static const RGBA32 kBlack = 0xFF000000;
    static const RGBA32 kWhite = 0xFFFFFFFF;
    static const RGBA32 kDarkGray = 0xFF808080;
    static const RGBA32 kGray = 0xFFA0A0A0;
    static const RGBA32 kLightGray = 0xFFC0C0C0;
    static const RGBA32 kTransparent = 0x00000000;
  
   private:
    RGBA32 color_;
  };
  
  inline bool operator==(const Color& a, const Color& b) {
    return a.Rgb() == b.Rgb();
  }
  
  inline bool operator!=(const Color& a, const Color& b) {
    return !(a == b);
  }
  
  PLATFORM_EXPORT Color ColorFromPremultipliedARGB(RGBA32);
  PLATFORM_EXPORT RGBA32 PremultipliedARGBFromColor(const Color&);
  
  }  // namespace blink
  
  #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_COLOR_H_
  