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 #include "SkColor.h" 16 #include "SkColorPriv.h" 17 #include "SkUnPreMultiply.h" 18 19 /** 20 * GrColor is 4 bytes for R, G, B, A, in a specific order defined below. Whether the color is 21 * premultiplied or not depends on the context in which it is being used. 22 */ 23 typedef uint32_t GrColor; 24 25 // shift amount to assign a component to a GrColor int 26 // These shift values are chosen for compatibility with GL attrib arrays 27 // ES doesn't allow BGRA vertex attrib order so if they were not in this order 28 // we'd have to swizzle in shaders. 29 #ifdef SK_CPU_BENDIAN 30 #define GrColor_SHIFT_R 24 31 #define GrColor_SHIFT_G 16 32 #define GrColor_SHIFT_B 8 33 #define GrColor_SHIFT_A 0 34 #else 35 #define GrColor_SHIFT_R 0 36 #define GrColor_SHIFT_G 8 37 #define GrColor_SHIFT_B 16 38 #define GrColor_SHIFT_A 24 39 #endif 40 41 /** 42 * Pack 4 components (RGBA) into a GrColor int 43 */ 44 static inline GrColor GrColorPackRGBA(unsigned r, unsigned g, unsigned b, unsigned a) { 45 SkASSERT((uint8_t)r == r); 46 SkASSERT((uint8_t)g == g); 47 SkASSERT((uint8_t)b == b); 48 SkASSERT((uint8_t)a == a); 49 return (r << GrColor_SHIFT_R) | 50 (g << GrColor_SHIFT_G) | 51 (b << GrColor_SHIFT_B) | 52 (a << GrColor_SHIFT_A); 53 } 54 55 /** 56 * Packs a color with an alpha channel replicated across all four channels. 57 */ 58 static inline GrColor GrColorPackA4(unsigned a) { 59 SkASSERT((uint8_t)a == a); 60 return (a << GrColor_SHIFT_R) | 61 (a << GrColor_SHIFT_G) | 62 (a << GrColor_SHIFT_B) | 63 (a << GrColor_SHIFT_A); 64 } 65 66 // extract a component (byte) from a GrColor int 67 68 #define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF) 69 #define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF) 70 #define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF) 71 #define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF) 72 73 /** 74 * Since premultiplied means that alpha >= color, we construct a color with 75 * each component==255 and alpha == 0 to be "illegal" 76 */ 77 #define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A)) 78 79 #define GrColor_WHITE 0xFFFFFFFF 80 #define GrColor_TRANSPARENT_BLACK 0x0 81 82 /** 83 * Assert in debug builds that a GrColor is premultiplied. 84 */ 85 static inline void GrColorIsPMAssert(GrColor SkDEBUGCODE(c)) { 86 #ifdef SK_DEBUG 87 unsigned a = GrColorUnpackA(c); 88 unsigned r = GrColorUnpackR(c); 89 unsigned g = GrColorUnpackG(c); 90 unsigned b = GrColorUnpackB(c); 91 92 SkASSERT(r <= a); 93 SkASSERT(g <= a); 94 SkASSERT(b <= a); 95 #endif 96 } 97 98 /** Inverts each color channel. */ 99 static inline GrColor GrInvertColor(GrColor c) { 100 U8CPU a = GrColorUnpackA(c); 101 U8CPU r = GrColorUnpackR(c); 102 U8CPU g = GrColorUnpackG(c); 103 U8CPU b = GrColorUnpackB(c); 104 return GrColorPackRGBA(0xff - r, 0xff - g, 0xff - b, 0xff - a); 105 } 106 107 static inline GrColor GrColorMul(GrColor c0, GrColor c1) { 108 U8CPU r = SkMulDiv255Round(GrColorUnpackR(c0), GrColorUnpackR(c1)); 109 U8CPU g = SkMulDiv255Round(GrColorUnpackG(c0), GrColorUnpackG(c1)); 110 U8CPU b = SkMulDiv255Round(GrColorUnpackB(c0), GrColorUnpackB(c1)); 111 U8CPU a = SkMulDiv255Round(GrColorUnpackA(c0), GrColorUnpackA(c1)); 112 return GrColorPackRGBA(r, g, b, a); 113 } 114 115 static inline GrColor GrColorSatAdd(GrColor c0, GrColor c1) { 116 unsigned r = SkTMin<unsigned>(GrColorUnpackR(c0) + GrColorUnpackR(c1), 0xff); 117 unsigned g = SkTMin<unsigned>(GrColorUnpackG(c0) + GrColorUnpackG(c1), 0xff); 118 unsigned b = SkTMin<unsigned>(GrColorUnpackB(c0) + GrColorUnpackB(c1), 0xff); 119 unsigned a = SkTMin<unsigned>(GrColorUnpackA(c0) + GrColorUnpackA(c1), 0xff); 120 return GrColorPackRGBA(r, g, b, a); 121 } 122 123 /** Converts a GrColor to an rgba array of GrGLfloat */ 124 static inline void GrColorToRGBAFloat(GrColor color, float rgba[4]) { 125 static const float ONE_OVER_255 = 1.f / 255.f; 126 rgba[0] = GrColorUnpackR(color) * ONE_OVER_255; 127 rgba[1] = GrColorUnpackG(color) * ONE_OVER_255; 128 rgba[2] = GrColorUnpackB(color) * ONE_OVER_255; 129 rgba[3] = GrColorUnpackA(color) * ONE_OVER_255; 130 } 131 132 /** Normalizes and coverts an uint8_t to a float. [0, 255] -> [0.0, 1.0] */ 133 static inline float GrNormalizeByteToFloat(uint8_t value) { 134 static const float ONE_OVER_255 = 1.f / 255.f; 135 return value * ONE_OVER_255; 136 } 137 138 /** Determines whether the color is opaque or not. */ 139 static inline bool GrColorIsOpaque(GrColor color) { 140 return (color & (0xFFU << GrColor_SHIFT_A)) == (0xFFU << GrColor_SHIFT_A); 141 } 142 143 static inline GrColor GrPremulColor(GrColor color) { 144 unsigned r = GrColorUnpackR(color); 145 unsigned g = GrColorUnpackG(color); 146 unsigned b = GrColorUnpackB(color); 147 unsigned a = GrColorUnpackA(color); 148 return GrColorPackRGBA(SkMulDiv255Round(r, a), 149 SkMulDiv255Round(g, a), 150 SkMulDiv255Round(b, a), 151 a); 152 } 153 154 /** Returns an unpremuled version of the GrColor. */ 155 static inline GrColor GrUnpremulColor(GrColor color) { 156 GrColorIsPMAssert(color); 157 unsigned r = GrColorUnpackR(color); 158 unsigned g = GrColorUnpackG(color); 159 unsigned b = GrColorUnpackB(color); 160 unsigned a = GrColorUnpackA(color); 161 SkPMColor colorPM = SkPackARGB32(a, r, g, b); 162 SkColor colorUPM = SkUnPreMultiply::PMColorToColor(colorPM); 163 164 r = SkColorGetR(colorUPM); 165 g = SkColorGetG(colorUPM); 166 b = SkColorGetB(colorUPM); 167 a = SkColorGetA(colorUPM); 168 169 return GrColorPackRGBA(r, g, b, a); 170 } 171 172 /** 173 * Flags used for bitfields of color components. They are defined so that the bit order reflects the 174 * GrColor shift order. 175 */ 176 enum GrColorComponentFlags { 177 kR_GrColorComponentFlag = 1 << (GrColor_SHIFT_R / 8), 178 kG_GrColorComponentFlag = 1 << (GrColor_SHIFT_G / 8), 179 kB_GrColorComponentFlag = 1 << (GrColor_SHIFT_B / 8), 180 kA_GrColorComponentFlag = 1 << (GrColor_SHIFT_A / 8), 181 182 kNone_GrColorComponentFlags = 0, 183 184 kRGB_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag | 185 kB_GrColorComponentFlag), 186 187 kRGBA_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag | 188 kB_GrColorComponentFlag | kA_GrColorComponentFlag) 189 }; 190 191 GR_MAKE_BITFIELD_OPS(GrColorComponentFlags) 192 193 static inline char GrColorComponentFlagToChar(GrColorComponentFlags component) { 194 SkASSERT(SkIsPow2(component)); 195 switch (component) { 196 case kR_GrColorComponentFlag: 197 return 'r'; 198 case kG_GrColorComponentFlag: 199 return 'g'; 200 case kB_GrColorComponentFlag: 201 return 'b'; 202 case kA_GrColorComponentFlag: 203 return 'a'; 204 default: 205 SkFAIL("Invalid color component flag."); 206 return '\0'; 207 } 208 } 209 210 static inline uint32_t GrPixelConfigComponentMask(GrPixelConfig config) { 211 SkASSERT(config >= 0 && config < kGrPixelConfigCnt); 212 static const uint32_t kFlags[] = { 213 0, // kUnknown_GrPixelConfig 214 kA_GrColorComponentFlag, // kAlpha_8_GrPixelConfig 215 kRGBA_GrColorComponentFlags, // kIndex_8_GrPixelConfig 216 kRGB_GrColorComponentFlags, // kRGB_565_GrPixelConfig 217 kRGBA_GrColorComponentFlags, // kRGBA_4444_GrPixelConfig 218 kRGBA_GrColorComponentFlags, // kRGBA_8888_GrPixelConfig 219 kRGBA_GrColorComponentFlags, // kBGRA_8888_GrPixelConfig 220 kRGBA_GrColorComponentFlags, // kSRGBA_8888_GrPixelConfig 221 kRGB_GrColorComponentFlags, // kETC1_GrPixelConfig 222 kA_GrColorComponentFlag, // kLATC_GrPixelConfig 223 kA_GrColorComponentFlag, // kR11_EAC_GrPixelConfig 224 kRGBA_GrColorComponentFlags, // kASTC_12x12_GrPixelConfig 225 kRGBA_GrColorComponentFlags, // kRGBA_float_GrPixelConfig 226 kA_GrColorComponentFlag, // kAlpha_16_GrPixelConfig 227 kRGBA_GrColorComponentFlags, // kRGBA_half_GrPixelConfig 228 }; 229 return kFlags[config]; 230 231 GR_STATIC_ASSERT(0 == kUnknown_GrPixelConfig); 232 GR_STATIC_ASSERT(1 == kAlpha_8_GrPixelConfig); 233 GR_STATIC_ASSERT(2 == kIndex_8_GrPixelConfig); 234 GR_STATIC_ASSERT(3 == kRGB_565_GrPixelConfig); 235 GR_STATIC_ASSERT(4 == kRGBA_4444_GrPixelConfig); 236 GR_STATIC_ASSERT(5 == kRGBA_8888_GrPixelConfig); 237 GR_STATIC_ASSERT(6 == kBGRA_8888_GrPixelConfig); 238 GR_STATIC_ASSERT(7 == kSRGBA_8888_GrPixelConfig); 239 GR_STATIC_ASSERT(8 == kETC1_GrPixelConfig); 240 GR_STATIC_ASSERT(9 == kLATC_GrPixelConfig); 241 GR_STATIC_ASSERT(10 == kR11_EAC_GrPixelConfig); 242 GR_STATIC_ASSERT(11 == kASTC_12x12_GrPixelConfig); 243 GR_STATIC_ASSERT(12 == kRGBA_float_GrPixelConfig); 244 GR_STATIC_ASSERT(13 == kAlpha_half_GrPixelConfig); 245 GR_STATIC_ASSERT(14 == kRGBA_half_GrPixelConfig); 246 GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFlags) == kGrPixelConfigCnt); 247 } 248 249 #endif 250
