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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 WebCore {
     45 
     46 class FloatRect;
     47 class IntSize;
     48 
     49 class PLATFORM_EXPORT Gradient : public RefCounted<Gradient> {
     50 public:
     51     static PassRefPtr<Gradient> create(const FloatPoint& p0, const FloatPoint& p1)
     52     {
     53         return adoptRef(new Gradient(p0, p1));
     54     }
     55     static PassRefPtr<Gradient> create(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio = 1)
     56     {
     57         return adoptRef(new Gradient(p0, r0, p1, r1, aspectRatio));
     58     }
     59     ~Gradient();
     60 
     61     struct ColorStop {
     62         float stop;
     63         Color color;
     64 
     65         ColorStop(float s, const Color& c) : stop(s), color(c) { }
     66     };
     67     void addColorStop(const ColorStop&);
     68     void addColorStop(float value, const Color& color) { addColorStop(ColorStop(value, color)); }
     69 
     70     bool hasAlpha() const;
     71     bool shaderChanged() const { return !m_gradient; }
     72 
     73     bool isRadial() const { return m_radial; }
     74     bool isZeroSize() const { return m_p0.x() == m_p1.x() && m_p0.y() == m_p1.y() && (!m_radial || m_r0 == m_r1); }
     75 
     76     const FloatPoint& p0() const { return m_p0; }
     77     const FloatPoint& p1() const { return m_p1; }
     78 
     79     void setP0(const FloatPoint& p)
     80     {
     81         if (m_p0 == p)
     82             return;
     83 
     84         m_p0 = p;
     85     }
     86 
     87     void setP1(const FloatPoint& p)
     88     {
     89         if (m_p1 == p)
     90             return;
     91 
     92         m_p1 = p;
     93     }
     94 
     95     float startRadius() const { return m_r0; }
     96     float endRadius() const { return m_r1; }
     97 
     98     void setStartRadius(float r)
     99     {
    100         if (m_r0 == r)
    101             return;
    102 
    103         m_r0 = r;
    104     }
    105 
    106     void setEndRadius(float r)
    107     {
    108         if (m_r1 == r)
    109             return;
    110 
    111         m_r1 = r;
    112     }
    113 
    114     float aspectRatio() const { return m_aspectRatio; }
    115 
    116     SkShader* shader();
    117 
    118     void setDrawsInPMColorSpace(bool drawInPMColorSpace);
    119 
    120     void setSpreadMethod(GradientSpreadMethod);
    121     GradientSpreadMethod spreadMethod() { return m_spreadMethod; }
    122     void setGradientSpaceTransform(const AffineTransform& gradientSpaceTransformation);
    123     AffineTransform gradientSpaceTransform() { return m_gradientSpaceTransformation; }
    124 
    125 private:
    126     Gradient(const FloatPoint& p0, const FloatPoint& p1);
    127     Gradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio);
    128 
    129     void destroyShader();
    130 
    131     void sortStopsIfNecessary();
    132 
    133     FloatPoint m_p0;
    134     FloatPoint m_p1;
    135     float m_r0;
    136     float m_r1;
    137     float m_aspectRatio; // For elliptical gradient, width / height.
    138     Vector<ColorStop, 2> m_stops;
    139     bool m_radial;
    140     bool m_stopsSorted;
    141     bool m_drawInPMColorSpace;
    142     GradientSpreadMethod m_spreadMethod;
    143     AffineTransform m_gradientSpaceTransformation;
    144 
    145     RefPtr<SkShader> m_gradient;
    146 };
    147 
    148 } // namespace WebCore
    149 
    150 #endif
    151