SkGradientShader.h revision 39123f4c0b4a02b7d94bac4f0348d6ec468b4382
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#define SK_SUPPORT_LEGACY_GRADIENT_FACTORIES 14 15/** \class SkGradientShader 16 17 SkGradientShader hosts factories for creating subclasses of SkShader that 18 render linear and radial gradients. 19*/ 20class SK_API SkGradientShader { 21public: 22 enum Flags { 23 /** By default gradients will interpolate their colors in unpremul space 24 * and then premultiply each of the results. By setting this flag, the 25 * gradients will premultiply their colors first, and then interpolate 26 * between them. 27 */ 28 kInterpolateColorsInPremul_Flag = 1 << 0, 29 }; 30 31 /** Returns a shader that generates a linear gradient between the two 32 specified points. 33 <p /> 34 CreateLinear returns a shader with a reference count of 1. 35 The caller should decrement the shader's reference count when done with the shader. 36 It is an error for count to be < 2. 37 @param pts The start and end points for the gradient. 38 @param colors The array[count] of colors, to be distributed between the two points 39 @param pos May be NULL. array[count] of SkScalars, or NULL, of the relative position of 40 each corresponding color in the colors array. If this is NULL, 41 the the colors are distributed evenly between the start and end point. 42 If this is not null, the values must begin with 0, end with 1.0, and 43 intermediate values must be strictly increasing. 44 @param count Must be >=2. The number of colors (and pos if not NULL) entries. 45 @param mode The tiling mode 46 */ 47 static SkShader* CreateLinear(const SkPoint pts[2], 48 const SkColor colors[], const SkScalar pos[], int count, 49 SkShader::TileMode mode, 50 uint32_t flags, const SkMatrix* localMatrix); 51 52 static SkShader* CreateLinear(const SkPoint pts[2], 53 const SkColor colors[], const SkScalar pos[], int count, 54 SkShader::TileMode mode) { 55 return CreateLinear(pts, colors, pos, count, mode, 0, NULL); 56 } 57 58#ifdef SK_SUPPORT_LEGACY_GRADIENT_FACTORIES 59 static SkShader* CreateLinear(const SkPoint pts[2], 60 const SkColor colors[], const SkScalar pos[], int count, 61 SkShader::TileMode mode, void* ignored, 62 uint32_t flags, const SkMatrix* localMatrix) { 63 return CreateLinear(pts, colors, pos, count, mode, flags, localMatrix); 64 } 65#endif 66 67 /** Returns a shader that generates a radial gradient given the center and radius. 68 <p /> 69 CreateRadial returns a shader with a reference count of 1. 70 The caller should decrement the shader's reference count when done with the shader. 71 It is an error for colorCount to be < 2, or for radius to be <= 0. 72 @param center The center of the circle for this gradient 73 @param radius Must be positive. The radius of the circle for this gradient 74 @param colors The array[count] of colors, to be distributed between the center and edge of the circle 75 @param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of 76 each corresponding color in the colors array. If this is NULL, 77 the the colors are distributed evenly between the center and edge of the circle. 78 If this is not null, the values must begin with 0, end with 1.0, and 79 intermediate values must be strictly increasing. 80 @param count Must be >= 2. The number of colors (and pos if not NULL) entries 81 @param mode The tiling mode 82 */ 83 static SkShader* CreateRadial(const SkPoint& center, SkScalar radius, 84 const SkColor colors[], const SkScalar pos[], int count, 85 SkShader::TileMode mode, 86 uint32_t flags, const SkMatrix* localMatrix); 87 88 static SkShader* CreateRadial(const SkPoint& center, SkScalar radius, 89 const SkColor colors[], const SkScalar pos[], int count, 90 SkShader::TileMode mode) { 91 return CreateRadial(center, radius, colors, pos, count, mode, 0, NULL); 92 } 93 94#ifdef SK_SUPPORT_LEGACY_GRADIENT_FACTORIES 95 static SkShader* CreateRadial(const SkPoint& center, SkScalar radius, 96 const SkColor colors[], const SkScalar pos[], int count, 97 SkShader::TileMode mode, void* ignored, 98 uint32_t flags, const SkMatrix* localMatrix) { 99 return CreateRadial(center, radius, colors, pos, count, mode, flags, localMatrix); 100 } 101#endif 102 103 /** Returns a shader that generates a radial gradient given the start position, start radius, end position and end radius. 104 <p /> 105 CreateTwoPointRadial 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, for startRadius or endRadius to be < 0, or for 108 startRadius to be equal to endRadius. 109 @param start The center of the start circle for this gradient 110 @param startRadius Must be positive. The radius of the start circle for this gradient. 111 @param end The center of the end circle for this gradient 112 @param endRadius Must be positive. The radius of the end circle for this gradient. 113 @param colors The array[count] of colors, to be distributed between the center and edge of the circle 114 @param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of 115 each corresponding color in the colors array. If this is NULL, 116 the the colors are distributed evenly between the center and edge of the circle. 117 If this is not null, the values must begin with 0, end with 1.0, and 118 intermediate values must be strictly increasing. 119 @param count Must be >= 2. The number of colors (and pos if not NULL) entries 120 @param mode The tiling mode 121 */ 122 static SkShader* CreateTwoPointRadial(const SkPoint& start, SkScalar startRadius, 123 const SkPoint& end, SkScalar endRadius, 124 const SkColor colors[], const SkScalar pos[], int count, 125 SkShader::TileMode mode, 126 uint32_t flags, const SkMatrix* localMatrix); 127 128 static SkShader* CreateTwoPointRadial(const SkPoint& start, SkScalar startRadius, 129 const SkPoint& end, SkScalar endRadius, 130 const SkColor colors[], const SkScalar pos[], int count, 131 SkShader::TileMode mode) { 132 return CreateTwoPointRadial(start, startRadius, end, endRadius, colors, pos, count, mode, 133 0, NULL); 134 } 135 136#ifdef SK_SUPPORT_LEGACY_GRADIENT_FACTORIES 137 static SkShader* CreateTwoPointRadial(const SkPoint& start, SkScalar startRadius, 138 const SkPoint& end, SkScalar endRadius, 139 const SkColor colors[], const SkScalar pos[], int count, 140 SkShader::TileMode mode, void* ignored, 141 uint32_t flags, const SkMatrix* localMatrix) { 142 return CreateTwoPointRadial(start, startRadius, end, endRadius, colors, pos, count, mode, 143 flags, localMatrix); 144 } 145#endif 146 147 /** 148 * Returns a shader that generates a conical gradient given two circles, or 149 * returns NULL if the inputs are invalid. The gradient interprets the 150 * two circles according to the following HTML spec. 151 * http://dev.w3.org/html5/2dcontext/#dom-context-2d-createradialgradient 152 */ 153 static SkShader* CreateTwoPointConical(const SkPoint& start, SkScalar startRadius, 154 const SkPoint& end, SkScalar endRadius, 155 const SkColor colors[], const SkScalar pos[], int count, 156 SkShader::TileMode mode, 157 uint32_t flags, const SkMatrix* localMatrix); 158 159 static SkShader* CreateTwoPointConical(const SkPoint& start, SkScalar startRadius, 160 const SkPoint& end, SkScalar endRadius, 161 const SkColor colors[], const SkScalar pos[], int count, 162 SkShader::TileMode mode) { 163 return CreateTwoPointConical(start, startRadius, end, endRadius, colors, pos, count, mode, 164 0, NULL); 165 } 166 167#ifdef SK_SUPPORT_LEGACY_GRADIENT_FACTORIES 168 static SkShader* CreateTwoPointConical(const SkPoint& start, SkScalar startRadius, 169 const SkPoint& end, SkScalar endRadius, 170 const SkColor colors[], const SkScalar pos[], int count, 171 SkShader::TileMode mode, void* ignored, 172 uint32_t flags, const SkMatrix* localMatrix) { 173 return CreateTwoPointConical(start, startRadius, end, endRadius, colors, pos, count, mode, 174 flags, localMatrix); 175 } 176#endif 177 178 /** Returns a shader that generates a sweep gradient given a center. 179 <p /> 180 CreateSweep returns a shader with a reference count of 1. 181 The caller should decrement the shader's reference count when done with the shader. 182 It is an error for colorCount to be < 2. 183 @param cx The X coordinate of the center of the sweep 184 @param cx The Y coordinate of the center of the sweep 185 @param colors The array[count] of colors, to be distributed around the center. 186 @param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of 187 each corresponding color in the colors array. If this is NULL, 188 the the colors are distributed evenly between the center and edge of the circle. 189 If this is not null, the values must begin with 0, end with 1.0, and 190 intermediate values must be strictly increasing. 191 @param count Must be >= 2. The number of colors (and pos if not NULL) entries 192 */ 193 static SkShader* CreateSweep(SkScalar cx, SkScalar cy, 194 const SkColor colors[], const SkScalar pos[], int count, 195 uint32_t flags, const SkMatrix* localMatrix); 196 197 static SkShader* CreateSweep(SkScalar cx, SkScalar cy, 198 const SkColor colors[], const SkScalar pos[], int count) { 199 return CreateSweep(cx, cy, colors, pos, count, 0, NULL); 200 } 201 202#ifdef SK_SUPPORT_LEGACY_GRADIENT_FACTORIES 203 static SkShader* CreateSweep(SkScalar cx, SkScalar cy, 204 const SkColor colors[], const SkScalar pos[], int count, 205 void* ignored, 206 uint32_t flags, const SkMatrix* localMatrix) { 207 return CreateSweep(cx, cy, colors, pos, count, flags, localMatrix); 208 } 209#endif 210 211 SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() 212}; 213 214#endif 215