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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/GraphicsTypes.h"
     35 #include "platform/transforms/AffineTransform.h"
     36 #include "wtf/PassRefPtr.h"
     37 #include "wtf/RefCounted.h"
     38 #include "wtf/RefPtr.h"
     39 #include "wtf/Vector.h"
     40 
     41 class SkShader;
     42 
     43 namespace WebCore {
     44 
     45 class Color;
     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         float red;
     64         float green;
     65         float blue;
     66         float alpha;
     67 
     68         ColorStop() : stop(0), red(0), green(0), blue(0), alpha(0) { }
     69         ColorStop(float s, float r, float g, float b, float a) : stop(s), red(r), green(g), blue(b), alpha(a) { }
     70     };
     71     void addColorStop(const ColorStop&);
     72     void addColorStop(float, const Color&);
     73 
     74     bool hasAlpha() const;
     75 
     76     bool isRadial() const { return m_radial; }
     77     bool isZeroSize() const { return m_p0.x() == m_p1.x() && m_p0.y() == m_p1.y() && (!m_radial || m_r0 == m_r1); }
     78 
     79     const FloatPoint& p0() const { return m_p0; }
     80     const FloatPoint& p1() const { return m_p1; }
     81 
     82     void setP0(const FloatPoint& p)
     83     {
     84         if (m_p0 == p)
     85             return;
     86 
     87         m_p0 = p;
     88     }
     89 
     90     void setP1(const FloatPoint& p)
     91     {
     92         if (m_p1 == p)
     93             return;
     94 
     95         m_p1 = p;
     96     }
     97 
     98     float startRadius() const { return m_r0; }
     99     float endRadius() const { return m_r1; }
    100 
    101     void setStartRadius(float r)
    102     {
    103         if (m_r0 == r)
    104             return;
    105 
    106         m_r0 = r;
    107     }
    108 
    109     void setEndRadius(float r)
    110     {
    111         if (m_r1 == r)
    112             return;
    113 
    114         m_r1 = r;
    115     }
    116 
    117     float aspectRatio() const { return m_aspectRatio; }
    118 
    119     SkShader* shader();
    120 
    121     void setStopsSorted(bool s) { m_stopsSorted = s; }
    122 
    123     void setDrawsInPMColorSpace(bool drawInPMColorSpace);
    124 
    125     void setSpreadMethod(GradientSpreadMethod);
    126     GradientSpreadMethod spreadMethod() { return m_spreadMethod; }
    127     void setGradientSpaceTransform(const AffineTransform& gradientSpaceTransformation);
    128     AffineTransform gradientSpaceTransform() { return m_gradientSpaceTransformation; }
    129 
    130 private:
    131     Gradient(const FloatPoint& p0, const FloatPoint& p1);
    132     Gradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio);
    133 
    134     void destroyShader();
    135 
    136     void sortStopsIfNecessary();
    137 
    138     // Keep any parameters relevant to rendering in sync with the structure in Gradient::hash().
    139     bool m_radial;
    140     FloatPoint m_p0;
    141     FloatPoint m_p1;
    142     float m_r0;
    143     float m_r1;
    144     float m_aspectRatio; // For elliptical gradient, width / height.
    145     mutable Vector<ColorStop, 2> m_stops;
    146     mutable bool m_stopsSorted;
    147     GradientSpreadMethod m_spreadMethod;
    148     AffineTransform m_gradientSpaceTransformation;
    149 
    150     bool m_drawInPMColorSpace;
    151 
    152     RefPtr<SkShader> m_gradient;
    153 };
    154 
    155 } // namespace WebCore
    156 
    157 #endif
    158