1 2/* 3 * Copyright 2010 Google Inc. 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 11#ifndef GrColor_DEFINED 12#define GrColor_DEFINED 13 14#include "GrTypes.h" 15 16/** 17 * GrColor is 4 bytes for R, G, B, A, in a specific order defined below. The components are stored 18 * premultiplied. 19 */ 20typedef uint32_t GrColor; 21 22// shift amount to assign a component to a GrColor int 23// These shift values are chosen for compatibility with GL attrib arrays 24// ES doesn't allow BGRA vertex attrib order so if they were not in this order 25// we'd have to swizzle in shaders. 26#ifdef SK_CPU_BENDIAN 27 #define GrColor_SHIFT_R 24 28 #define GrColor_SHIFT_G 16 29 #define GrColor_SHIFT_B 8 30 #define GrColor_SHIFT_A 0 31#else 32 #define GrColor_SHIFT_R 0 33 #define GrColor_SHIFT_G 8 34 #define GrColor_SHIFT_B 16 35 #define GrColor_SHIFT_A 24 36#endif 37 38/** 39 * Pack 4 components (RGBA) into a GrColor int 40 */ 41static inline GrColor GrColorPackRGBA(unsigned r, unsigned g, 42 unsigned b, unsigned a) { 43 SkASSERT((uint8_t)r == r); 44 SkASSERT((uint8_t)g == g); 45 SkASSERT((uint8_t)b == b); 46 SkASSERT((uint8_t)a == a); 47 return (r << GrColor_SHIFT_R) | 48 (g << GrColor_SHIFT_G) | 49 (b << GrColor_SHIFT_B) | 50 (a << GrColor_SHIFT_A); 51} 52 53// extract a component (byte) from a GrColor int 54 55#define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF) 56#define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF) 57#define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF) 58#define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF) 59 60/** 61 * Since premultiplied means that alpha >= color, we construct a color with 62 * each component==255 and alpha == 0 to be "illegal" 63 */ 64#define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A)) 65 66/** 67 * Assert in debug builds that a GrColor is premultiplied. 68 */ 69static inline void GrColorIsPMAssert(GrColor c) { 70#ifdef SK_DEBUG 71 unsigned a = GrColorUnpackA(c); 72 unsigned r = GrColorUnpackR(c); 73 unsigned g = GrColorUnpackG(c); 74 unsigned b = GrColorUnpackB(c); 75 76 SkASSERT(r <= a); 77 SkASSERT(g <= a); 78 SkASSERT(b <= a); 79#endif 80} 81 82/** Converts a GrColor to an rgba array of GrGLfloat */ 83static inline void GrColorToRGBAFloat(GrColor color, float rgba[4]) { 84 static const float ONE_OVER_255 = 1.f / 255.f; 85 rgba[0] = GrColorUnpackR(color) * ONE_OVER_255; 86 rgba[1] = GrColorUnpackG(color) * ONE_OVER_255; 87 rgba[2] = GrColorUnpackB(color) * ONE_OVER_255; 88 rgba[3] = GrColorUnpackA(color) * ONE_OVER_255; 89} 90 91/** 92 * Flags used for bitfields of color components. They are defined so that the bit order reflects the 93 * GrColor shift order. 94 */ 95enum GrColorComponentFlags { 96 kR_GrColorComponentFlag = 1 << (GrColor_SHIFT_R / 8), 97 kG_GrColorComponentFlag = 1 << (GrColor_SHIFT_G / 8), 98 kB_GrColorComponentFlag = 1 << (GrColor_SHIFT_B / 8), 99 kA_GrColorComponentFlag = 1 << (GrColor_SHIFT_A / 8), 100 101 kRGB_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag | 102 kB_GrColorComponentFlag), 103 104 kRGBA_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag | 105 kB_GrColorComponentFlag | kA_GrColorComponentFlag) 106}; 107 108static inline char GrColorComponentFlagToChar(GrColorComponentFlags component) { 109 SkASSERT(SkIsPow2(component)); 110 switch (component) { 111 case kR_GrColorComponentFlag: 112 return 'r'; 113 case kG_GrColorComponentFlag: 114 return 'g'; 115 case kB_GrColorComponentFlag: 116 return 'b'; 117 case kA_GrColorComponentFlag: 118 return 'a'; 119 default: 120 SkFAIL("Invalid color component flag."); 121 return '\0'; 122 } 123} 124 125static inline uint32_t GrPixelConfigComponentMask(GrPixelConfig config) { 126 SkASSERT(config >= 0 && config < kGrPixelConfigCnt); 127 static const uint32_t kFlags[] = { 128 0, // kUnknown_GrPixelConfig 129 kA_GrColorComponentFlag, // kAlpha_8_GrPixelConfig 130 kRGBA_GrColorComponentFlags, // kIndex_8_GrPixelConfig 131 kRGB_GrColorComponentFlags, // kRGB_565_GrPixelConfig 132 kRGBA_GrColorComponentFlags, // kRGBA_4444_GrPixelConfig 133 kRGBA_GrColorComponentFlags, // kRGBA_8888_GrPixelConfig 134 kRGBA_GrColorComponentFlags, // kBGRA_8888_GrPixelConfig 135 kRGB_GrColorComponentFlags, // kETC1_GrPixelConfig 136 kA_GrColorComponentFlag, // kLATC_GrPixelConfig 137 }; 138 return kFlags[config]; 139 140 GR_STATIC_ASSERT(0 == kUnknown_GrPixelConfig); 141 GR_STATIC_ASSERT(1 == kAlpha_8_GrPixelConfig); 142 GR_STATIC_ASSERT(2 == kIndex_8_GrPixelConfig); 143 GR_STATIC_ASSERT(3 == kRGB_565_GrPixelConfig); 144 GR_STATIC_ASSERT(4 == kRGBA_4444_GrPixelConfig); 145 GR_STATIC_ASSERT(5 == kRGBA_8888_GrPixelConfig); 146 GR_STATIC_ASSERT(6 == kBGRA_8888_GrPixelConfig); 147 GR_STATIC_ASSERT(7 == kETC1_GrPixelConfig); 148 GR_STATIC_ASSERT(8 == kLATC_GrPixelConfig); 149 GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFlags) == kGrPixelConfigCnt); 150} 151 152#endif 153