1 /* 2 * Copyright 2006 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkGradientShader_DEFINED 9 #define SkGradientShader_DEFINED 10 11 #include "SkShader.h" 12 13 /** \class SkGradientShader 14 15 SkGradientShader hosts factories for creating subclasses of SkShader that 16 render linear and radial gradients. 17 */ 18 class SK_API SkGradientShader { 19 public: 20 enum Flags { 21 /** By default gradients will interpolate their colors in unpremul space 22 * and then premultiply each of the results. By setting this flag, the 23 * gradients will premultiply their colors first, and then interpolate 24 * between them. 25 */ 26 kInterpolateColorsInPremul_Flag = 1 << 0, 27 }; 28 29 /** Returns a shader that generates a linear gradient between the two 30 specified points. 31 <p /> 32 CreateLinear returns a shader with a reference count of 1. 33 The caller should decrement the shader's reference count when done with the shader. 34 It is an error for count to be < 2. 35 @param pts The start and end points for the gradient. 36 @param colors The array[count] of colors, to be distributed between the two points 37 @param pos May be NULL. array[count] of SkScalars, or NULL, of the relative position of 38 each corresponding color in the colors array. If this is NULL, 39 the the colors are distributed evenly between the start and end point. 40 If this is not null, the values must begin with 0, end with 1.0, and 41 intermediate values must be strictly increasing. 42 @param count Must be >=2. The number of colors (and pos if not NULL) entries. 43 @param mode The tiling mode 44 */ 45 static SkShader* CreateLinear(const SkPoint pts[2], 46 const SkColor colors[], const SkScalar pos[], int count, 47 SkShader::TileMode mode, 48 uint32_t flags, const SkMatrix* localMatrix); 49 50 static SkShader* CreateLinear(const SkPoint pts[2], 51 const SkColor colors[], const SkScalar pos[], int count, 52 SkShader::TileMode mode) { 53 return CreateLinear(pts, colors, pos, count, mode, 0, NULL); 54 } 55 56 /** Returns a shader that generates a radial gradient given the center and radius. 57 <p /> 58 CreateRadial returns a shader with a reference count of 1. 59 The caller should decrement the shader's reference count when done with the shader. 60 It is an error for colorCount to be < 2, or for radius to be <= 0. 61 @param center The center of the circle for this gradient 62 @param radius Must be positive. The radius of the circle for this gradient 63 @param colors The array[count] of colors, to be distributed between the center and edge of the circle 64 @param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of 65 each corresponding color in the colors array. If this is NULL, 66 the the colors are distributed evenly between the center and edge of the circle. 67 If this is not null, the values must begin with 0, end with 1.0, and 68 intermediate values must be strictly increasing. 69 @param count Must be >= 2. The number of colors (and pos if not NULL) entries 70 @param mode The tiling mode 71 */ 72 static SkShader* CreateRadial(const SkPoint& center, SkScalar radius, 73 const SkColor colors[], const SkScalar pos[], int count, 74 SkShader::TileMode mode, 75 uint32_t flags, const SkMatrix* localMatrix); 76 77 static SkShader* CreateRadial(const SkPoint& center, SkScalar radius, 78 const SkColor colors[], const SkScalar pos[], int count, 79 SkShader::TileMode mode) { 80 return CreateRadial(center, radius, colors, pos, count, mode, 0, NULL); 81 } 82 83 /** 84 * Returns a shader that generates a conical gradient given two circles, or 85 * returns NULL if the inputs are invalid. The gradient interprets the 86 * two circles according to the following HTML spec. 87 * http://dev.w3.org/html5/2dcontext/#dom-context-2d-createradialgradient 88 */ 89 static SkShader* CreateTwoPointConical(const SkPoint& start, SkScalar startRadius, 90 const SkPoint& end, SkScalar endRadius, 91 const SkColor colors[], const SkScalar pos[], int count, 92 SkShader::TileMode mode, 93 uint32_t flags, const SkMatrix* localMatrix); 94 95 static SkShader* CreateTwoPointConical(const SkPoint& start, SkScalar startRadius, 96 const SkPoint& end, SkScalar endRadius, 97 const SkColor colors[], const SkScalar pos[], int count, 98 SkShader::TileMode mode) { 99 return CreateTwoPointConical(start, startRadius, end, endRadius, colors, pos, count, mode, 100 0, NULL); 101 } 102 103 /** Returns a shader that generates a sweep gradient given a center. 104 <p /> 105 CreateSweep returns a shader with a reference count of 1. 106 The caller should decrement the shader's reference count when done with the shader. 107 It is an error for colorCount to be < 2. 108 @param cx The X coordinate of the center of the sweep 109 @param cx The Y coordinate of the center of the sweep 110 @param colors The array[count] of colors, to be distributed around the center. 111 @param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of 112 each corresponding color in the colors array. If this is NULL, 113 the the colors are distributed evenly between the center and edge of the circle. 114 If this is not null, the values must begin with 0, end with 1.0, and 115 intermediate values must be strictly increasing. 116 @param count Must be >= 2. The number of colors (and pos if not NULL) entries 117 */ 118 static SkShader* CreateSweep(SkScalar cx, SkScalar cy, 119 const SkColor colors[], const SkScalar pos[], int count, 120 uint32_t flags, const SkMatrix* localMatrix); 121 122 static SkShader* CreateSweep(SkScalar cx, SkScalar cy, 123 const SkColor colors[], const SkScalar pos[], int count) { 124 return CreateSweep(cx, cy, colors, pos, count, 0, NULL); 125 } 126 127 SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() 128 }; 129 130 #endif 131
