SkColorShader.h revision 87fcd950198a16211b3988610beebb5ca5bcf323 
1
2/*
3 * Copyright 2007 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#ifndef SkColorShader_DEFINED
11#define SkColorShader_DEFINED
12
13#include "SkShader.h"
14
15/** \class SkColorShader
16    A Shader that represents a single color. In general, this effect can be
17    accomplished by just using the color field on the paint, but if an
18    actual shader object is needed, this provides that feature.
19*/
20class SK_API SkColorShader : public SkShader {
21public:
22    /** Create a ColorShader that will inherit its color from the Paint
23        at draw time.
24    */
25    SkColorShader();
26
27    /** Create a ColorShader that ignores the color in the paint, and uses the
28        specified color. Note: like all shaders, at draw time the paint's alpha
29        will be respected, and is applied to the specified color.
30    */
31    SkColorShader(SkColor c);
32
33    virtual bool isOpaque() const SK_OVERRIDE;
34
35    virtual SkShader::Context* createContext(const SkBitmap& device,
36                                             const SkPaint& paint,
37                                             const SkMatrix& matrix,
38                                             void* storage) const SK_OVERRIDE;
39
40    virtual size_t contextSize() const SK_OVERRIDE {
41        return sizeof(ColorShaderContext);
42    }
43
44    class ColorShaderContext : public SkShader::Context {
45    public:
46        ColorShaderContext(const SkColorShader& shader, const SkBitmap& device,
47                           const SkPaint& paint, const SkMatrix& matrix);
48
49        virtual uint32_t getFlags() const SK_OVERRIDE;
50        virtual uint8_t getSpan16Alpha() const SK_OVERRIDE;
51        virtual void shadeSpan(int x, int y, SkPMColor span[], int count) SK_OVERRIDE;
52        virtual void shadeSpan16(int x, int y, uint16_t span[], int count) SK_OVERRIDE;
53        virtual void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) SK_OVERRIDE;
54
55    private:
56        SkPMColor   fPMColor;
57        uint32_t    fFlags;
58        uint16_t    fColor16;
59
60        typedef SkShader::Context INHERITED;
61    };
62
63    // we return false for this, use asAGradient
64    virtual BitmapType asABitmap(SkBitmap* outTexture,
65                                 SkMatrix* outMatrix,
66                                 TileMode xy[2]) const SK_OVERRIDE;
67
68    virtual GradientType asAGradient(GradientInfo* info) const SK_OVERRIDE;
69
70    SK_TO_STRING_OVERRIDE()
71    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkColorShader)
72
73protected:
74    SkColorShader(SkReadBuffer&);
75    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
76
77private:
78    SkColor     fColor;         // ignored if fInheritColor is true
79    SkBool8     fInheritColor;
80
81    typedef SkShader INHERITED;
82};
83
84#endif
85