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      1 /*
      2  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
      3  * Copyright (C) 2007 Alp Toker <alp (at) 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 
     42 class SkShader;
     43 
     44 namespace blink {
     45 
     46 class PLATFORM_EXPORT Gradient : public RefCounted<Gradient> {
     47 public:
     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 
    122 private:
    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