1 /* 2 * Copyright 2008 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 9 #ifndef SkDither_DEFINED 10 #define SkDither_DEFINED 11 12 #include "SkColorData.h" 13 14 #define SK_DitherValueMax4444 15 15 #define SK_DitherValueMax565 7 16 17 /* need to use macros for bit-counts for each component, and then 18 move these into SkColorData.h 19 */ 20 21 #define SkDITHER_R32_FOR_565_MACRO(r, d) (r + d - (r >> 5)) 22 #define SkDITHER_G32_FOR_565_MACRO(g, d) (g + (d >> 1) - (g >> 6)) 23 #define SkDITHER_B32_FOR_565_MACRO(b, d) (b + d - (b >> 5)) 24 25 #define SkDITHER_A32_FOR_4444_MACRO(a, d) (a + 15 - (a >> 4)) 26 #define SkDITHER_R32_FOR_4444_MACRO(r, d) (r + d - (r >> 4)) 27 #define SkDITHER_G32_FOR_4444_MACRO(g, d) (g + d - (g >> 4)) 28 #define SkDITHER_B32_FOR_4444_MACRO(b, d) (b + d - (b >> 4)) 29 30 #ifdef SK_DEBUG 31 inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d) 32 { 33 SkASSERT(d <= SK_DitherValueMax565); 34 SkA32Assert(r); 35 r = SkDITHER_R32_FOR_565_MACRO(r, d); 36 SkA32Assert(r); 37 return r; 38 } 39 inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d) 40 { 41 SkASSERT(d <= SK_DitherValueMax565); 42 SkG32Assert(g); 43 g = SkDITHER_G32_FOR_565_MACRO(g, d); 44 SkG32Assert(g); 45 return g; 46 } 47 inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d) 48 { 49 SkASSERT(d <= SK_DitherValueMax565); 50 SkB32Assert(b); 51 b = SkDITHER_B32_FOR_565_MACRO(b, d); 52 SkB32Assert(b); 53 return b; 54 } 55 #else 56 #define SkDITHER_R32_FOR_565(r, d) SkDITHER_R32_FOR_565_MACRO(r, d) 57 #define SkDITHER_G32_FOR_565(g, d) SkDITHER_G32_FOR_565_MACRO(g, d) 58 #define SkDITHER_B32_FOR_565(b, d) SkDITHER_B32_FOR_565_MACRO(b, d) 59 #endif 60 61 #define SkDITHER_R32To565(r, d) SkR32ToR16(SkDITHER_R32_FOR_565(r, d)) 62 #define SkDITHER_G32To565(g, d) SkG32ToG16(SkDITHER_G32_FOR_565(g, d)) 63 #define SkDITHER_B32To565(b, d) SkB32ToB16(SkDITHER_B32_FOR_565(b, d)) 64 65 #define SkDITHER_A32To4444(a, d) SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d)) 66 #define SkDITHER_R32To4444(r, d) SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d)) 67 #define SkDITHER_G32To4444(g, d) SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d)) 68 #define SkDITHER_B32To4444(b, d) SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d)) 69 70 static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither) 71 { 72 SkASSERT(dither <= SK_DitherValueMax565); 73 74 unsigned sa = SkGetPackedA32(c); 75 dither = SkAlphaMul(dither, SkAlpha255To256(sa)); 76 77 unsigned sr = SkGetPackedR32(c); 78 unsigned sg = SkGetPackedG32(c); 79 unsigned sb = SkGetPackedB32(c); 80 sr = SkDITHER_R32_FOR_565(sr, dither); 81 sg = SkDITHER_G32_FOR_565(sg, dither); 82 sb = SkDITHER_B32_FOR_565(sb, dither); 83 84 return SkPackARGB32(sa, sr, sg, sb); 85 } 86 87 static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither) 88 { 89 SkASSERT(dither <= SK_DitherValueMax565); 90 91 unsigned sr = SkGetPackedR32(c); 92 unsigned sg = SkGetPackedG32(c); 93 unsigned sb = SkGetPackedB32(c); 94 sr = SkDITHER_R32_FOR_565(sr, dither); 95 sg = SkDITHER_G32_FOR_565(sg, dither); 96 sb = SkDITHER_B32_FOR_565(sb, dither); 97 98 return SkPackARGB32(0xFF, sr, sg, sb); 99 } 100 101 static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b, 102 unsigned dither) 103 { 104 SkASSERT(dither <= SK_DitherValueMax565); 105 r = SkDITHER_R32To565(r, dither); 106 g = SkDITHER_G32To565(g, dither); 107 b = SkDITHER_B32To565(b, dither); 108 return SkPackRGB16(r, g, b); 109 } 110 111 static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither) 112 { 113 SkASSERT(dither <= SK_DitherValueMax565); 114 115 unsigned sr = SkGetPackedR32(c); 116 unsigned sg = SkGetPackedG32(c); 117 unsigned sb = SkGetPackedB32(c); 118 sr = SkDITHER_R32To565(sr, dither); 119 sg = SkDITHER_G32To565(sg, dither); 120 sb = SkDITHER_B32To565(sb, dither); 121 122 return SkPackRGB16(sr, sg, sb); 123 } 124 125 static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither) 126 { 127 SkASSERT(dither <= SK_DitherValueMax565); 128 dither = SkAlphaMul(dither, SkAlpha255To256(sa)); 129 130 unsigned sr = SkGetPackedR32(c); 131 unsigned sg = SkGetPackedG32(c); 132 unsigned sb = SkGetPackedB32(c); 133 sr = SkDITHER_R32To565(sr, dither); 134 sg = SkDITHER_G32To565(sg, dither); 135 sb = SkDITHER_B32To565(sb, dither); 136 137 return SkPackRGB16(sr, sg, sb); 138 } 139 140 ///////////////////////// 4444 141 142 static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g, 143 U8CPU b, unsigned dither) 144 { 145 dither = SkAlphaMul(dither, SkAlpha255To256(a)); 146 147 a = SkDITHER_A32To4444(a, dither); 148 r = SkDITHER_R32To4444(r, dither); 149 g = SkDITHER_G32To4444(g, dither); 150 b = SkDITHER_B32To4444(b, dither); 151 152 return SkPackARGB4444(a, r, g, b); 153 } 154 155 static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither) 156 { 157 unsigned a = SkGetPackedA32(c); 158 unsigned r = SkGetPackedR32(c); 159 unsigned g = SkGetPackedG32(c); 160 unsigned b = SkGetPackedB32(c); 161 162 dither = SkAlphaMul(dither, SkAlpha255To256(a)); 163 164 a = SkDITHER_A32To4444(a, dither); 165 r = SkDITHER_R32To4444(r, dither); 166 g = SkDITHER_G32To4444(g, dither); 167 b = SkDITHER_B32To4444(b, dither); 168 169 return SkPackARGB4444(a, r, g, b); 170 } 171 172 // TODO: need dither routines for 565 -> 4444 173 174 // this toggles between a 4x4 and a 1x4 array 175 //#define ENABLE_DITHER_MATRIX_4X4 176 177 #ifdef ENABLE_DITHER_MATRIX_4X4 178 extern const uint8_t gDitherMatrix_4Bit_4X4[4][4]; 179 extern const uint8_t gDitherMatrix_3Bit_4X4[4][4]; 180 181 #define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3] 182 #define DITHER_565_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3] 183 184 #define DITHER_VALUE(x) dither_scan[(x) & 3] 185 #else 186 extern SK_API const uint16_t gDitherMatrix_4Bit_16[4]; 187 extern SK_API const uint16_t gDitherMatrix_3Bit_16[4]; 188 189 #define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3] 190 #define DITHER_565_SCAN(y) const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3] 191 192 #define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF) 193 #endif 194 195 #define DITHER_INC_X(x) ++(x) 196 197 #endif 198
