1/*
2 * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
3 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
4 * Copyright (C) 2008 Torch Mobile, Inc.
5 * Copyright (C) 2013 Google Inc. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
20 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
23 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
24 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef Gradient_h
30#define Gradient_h
31
32#include "platform/PlatformExport.h"
33#include "platform/geometry/FloatPoint.h"
34#include "platform/graphics/Color.h"
35#include "platform/graphics/GraphicsTypes.h"
36#include "platform/transforms/AffineTransform.h"
37#include "wtf/PassRefPtr.h"
38#include "wtf/RefCounted.h"
39#include "wtf/RefPtr.h"
40#include "wtf/Vector.h"
41
42class SkShader;
43
44namespace blink {
45
46class PLATFORM_EXPORT Gradient : public RefCounted<Gradient> {
47public:
48    static PassRefPtr<Gradient> create(const FloatPoint& p0, const FloatPoint& p1)
49    {
50        return adoptRef(new Gradient(p0, p1));
51    }
52    static PassRefPtr<Gradient> create(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio = 1)
53    {
54        return adoptRef(new Gradient(p0, r0, p1, r1, aspectRatio));
55    }
56    ~Gradient();
57
58    struct ColorStop {
59        float stop;
60        Color color;
61
62        ColorStop(float s, const Color& c) : stop(s), color(c) { }
63    };
64    void addColorStop(const ColorStop&);
65    void addColorStop(float value, const Color& color) { addColorStop(ColorStop(value, color)); }
66
67    bool hasAlpha() const;
68    bool shaderChanged() const { return !m_gradient; }
69
70    bool isRadial() const { return m_radial; }
71    bool isZeroSize() const { return m_p0.x() == m_p1.x() && m_p0.y() == m_p1.y() && (!m_radial || m_r0 == m_r1); }
72
73    const FloatPoint& p0() const { return m_p0; }
74    const FloatPoint& p1() const { return m_p1; }
75
76    void setP0(const FloatPoint& p)
77    {
78        if (m_p0 == p)
79            return;
80
81        m_p0 = p;
82    }
83
84    void setP1(const FloatPoint& p)
85    {
86        if (m_p1 == p)
87            return;
88
89        m_p1 = p;
90    }
91
92    float startRadius() const { return m_r0; }
93    float endRadius() const { return m_r1; }
94
95    void setStartRadius(float r)
96    {
97        if (m_r0 == r)
98            return;
99
100        m_r0 = r;
101    }
102
103    void setEndRadius(float r)
104    {
105        if (m_r1 == r)
106            return;
107
108        m_r1 = r;
109    }
110
111    float aspectRatio() const { return m_aspectRatio; }
112
113    SkShader* shader();
114
115    void setDrawsInPMColorSpace(bool drawInPMColorSpace);
116
117    void setSpreadMethod(GradientSpreadMethod);
118    GradientSpreadMethod spreadMethod() { return m_spreadMethod; }
119    void setGradientSpaceTransform(const AffineTransform& gradientSpaceTransformation);
120    AffineTransform gradientSpaceTransform() { return m_gradientSpaceTransformation; }
121
122private:
123    Gradient(const FloatPoint& p0, const FloatPoint& p1);
124    Gradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio);
125
126    void destroyShader();
127
128    void sortStopsIfNecessary();
129
130    FloatPoint m_p0;
131    FloatPoint m_p1;
132    float m_r0;
133    float m_r1;
134    float m_aspectRatio; // For elliptical gradient, width / height.
135    Vector<ColorStop, 2> m_stops;
136    bool m_radial;
137    bool m_stopsSorted;
138    bool m_drawInPMColorSpace;
139    GradientSpreadMethod m_spreadMethod;
140    AffineTransform m_gradientSpaceTransformation;
141
142    RefPtr<SkShader> m_gradient;
143};
144
145} // namespace blink
146
147#endif
148