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 "platform/animation/AnimationUtilities.h"
30#include "wtf/FastAllocBase.h"
31#include "wtf/Forward.h"
32#include "wtf/unicode/Unicode.h"
33
34namespace blink {
35
36class Color;
37
38typedef unsigned RGBA32; // RGBA quadruplet
39
40PLATFORM_EXPORT RGBA32 makeRGB(int r, int g, int b);
41PLATFORM_EXPORT RGBA32 makeRGBA(int r, int g, int b, int a);
42
43PLATFORM_EXPORT RGBA32 colorWithOverrideAlpha(RGBA32 color, float overrideAlpha);
44PLATFORM_EXPORT RGBA32 makeRGBA32FromFloats(float r, float g, float b, float a);
45PLATFORM_EXPORT RGBA32 makeRGBAFromHSLA(double h, double s, double l, double a);
46PLATFORM_EXPORT RGBA32 makeRGBAFromCMYKA(float c, float m, float y, float k, float a);
47
48PLATFORM_EXPORT int differenceSquared(const Color&, const Color&);
49
50inline int redChannel(RGBA32 color) { return (color >> 16) & 0xFF; }
51inline int greenChannel(RGBA32 color) { return (color >> 8) & 0xFF; }
52inline int blueChannel(RGBA32 color) { return color & 0xFF; }
53inline int alphaChannel(RGBA32 color) { return (color >> 24) & 0xFF; }
54
55struct NamedColor {
56    const char* name;
57    unsigned ARGBValue;
58};
59
60const NamedColor* findColor(register const char* str, register unsigned len);
61
62class PLATFORM_EXPORT Color {
63    WTF_MAKE_FAST_ALLOCATED;
64public:
65    Color() : m_color(Color::transparent) { }
66    Color(RGBA32 color) : m_color(color) { }
67    Color(int r, int g, int b) : m_color(makeRGB(r, g, b)) { }
68    Color(int r, int g, int b, int a) : m_color(makeRGBA(r, g, b, a)) { }
69    // Color is currently limited to 32bit RGBA, perhaps some day we'll support better colors
70    Color(float r, float g, float b, float a) : m_color(makeRGBA32FromFloats(r, g, b, a)) { }
71    // Creates a new color from the specific CMYK and alpha values.
72    Color(float c, float m, float y, float k, float a) : m_color(makeRGBAFromCMYKA(c, m, y, k, a)) { }
73
74    static Color createUnchecked(int r, int g, int b)
75    {
76        RGBA32 color = 0xFF000000 | r << 16 | g << 8 | b;
77        return Color(color);
78    }
79    static Color createUnchecked(int r, int g, int b, int a)
80    {
81        RGBA32 color = a << 24 | r << 16 | g << 8 | b;
82        return Color(color);
83    }
84
85    // Returns the color serialized according to HTML5
86    // - http://www.whatwg.org/specs/web-apps/current-work/#serialization-of-a-color
87    String serialized() const;
88
89    // Returns the color serialized according to CSSOM
90    // - http://dev.w3.org/csswg/cssom/#serialize-a-css-component-value
91    String serializedAsCSSComponentValue() const;
92
93    // Returns the color serialized as either #RRGGBB or #RRGGBBAA
94    // The latter format is not a valid CSS color, and should only be seen in DRT dumps.
95    String nameForRenderTreeAsText() const;
96
97    // Returns whether parsing succeeded. The resulting Color is arbitrary
98    // if parsing fails.
99    bool setFromString(const String&);
100    bool setNamedColor(const String&);
101
102    bool hasAlpha() const { return alpha() < 255; }
103
104    int red() const { return redChannel(m_color); }
105    int green() const { return greenChannel(m_color); }
106    int blue() const { return blueChannel(m_color); }
107    int alpha() const { return alphaChannel(m_color); }
108
109    RGBA32 rgb() const { return m_color; } // Preserve the alpha.
110    void setRGB(int r, int g, int b) { m_color = makeRGB(r, g, b); }
111    void setRGB(RGBA32 rgb) { m_color = rgb; }
112    void getRGBA(float& r, float& g, float& b, float& a) const;
113    void getRGBA(double& r, double& g, double& b, double& a) const;
114    void getHSL(double& h, double& s, double& l) const;
115
116    Color light() const;
117    Color dark() const;
118
119    Color combineWithAlpha(float otherAlpha) const;
120
121    // This is an implementation of Porter-Duff's "source-over" equation
122    Color blend(const Color&) const;
123    Color blendWithWhite() const;
124
125    static bool parseHexColor(const String&, RGBA32&);
126    static bool parseHexColor(const LChar*, unsigned, RGBA32&);
127    static bool parseHexColor(const UChar*, unsigned, RGBA32&);
128
129    static const RGBA32 black = 0xFF000000;
130    static const RGBA32 white = 0xFFFFFFFF;
131    static const RGBA32 darkGray = 0xFF808080;
132    static const RGBA32 gray = 0xFFA0A0A0;
133    static const RGBA32 lightGray = 0xFFC0C0C0;
134    static const RGBA32 transparent = 0x00000000;
135
136private:
137    RGBA32 m_color;
138};
139
140inline bool operator==(const Color& a, const Color& b)
141{
142    return a.rgb() == b.rgb();
143}
144
145inline bool operator!=(const Color& a, const Color& b)
146{
147    return !(a == b);
148}
149
150PLATFORM_EXPORT Color colorFromPremultipliedARGB(RGBA32);
151PLATFORM_EXPORT RGBA32 premultipliedARGBFromColor(const Color&);
152
153inline Color blend(const Color& from, const Color& to, double progress, bool blendPremultiplied = true)
154{
155    if (blendPremultiplied) {
156        // Contrary to the name, RGBA32 actually stores ARGB, so we can initialize Color directly from premultipliedARGBFromColor().
157        // Also, premultipliedARGBFromColor() bails on zero alpha, so special-case that.
158        Color premultFrom = from.alpha() ? premultipliedARGBFromColor(from) : 0;
159        Color premultTo = to.alpha() ? premultipliedARGBFromColor(to) : 0;
160
161        Color premultBlended(blend(premultFrom.red(), premultTo.red(), progress),
162                             blend(premultFrom.green(), premultTo.green(), progress),
163                             blend(premultFrom.blue(), premultTo.blue(), progress),
164                             blend(premultFrom.alpha(), premultTo.alpha(), progress));
165
166        return Color(colorFromPremultipliedARGB(premultBlended.rgb()));
167    }
168
169    return Color(blend(from.red(), to.red(), progress),
170                 blend(from.green(), to.green(), progress),
171                 blend(from.blue(), to.blue(), progress),
172                 blend(from.alpha(), to.alpha(), progress));
173}
174} // namespace blink
175
176#endif // Color_h
177