1 2 /* 3 * Copyright 2008 The Android Open Source Project 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 #ifndef SkDither_DEFINED 11 #define SkDither_DEFINED 12 13 #include "SkColorPriv.h" 14 15 #define SK_DitherValueMax4444 15 16 #define SK_DitherValueMax565 7 17 18 /* need to use macros for bit-counts for each component, and then 19 move these into SkColorPriv.h 20 */ 21 22 #define SkDITHER_R32_FOR_565_MACRO(r, d) (r + d - (r >> 5)) 23 #define SkDITHER_G32_FOR_565_MACRO(g, d) (g + (d >> 1) - (g >> 6)) 24 #define SkDITHER_B32_FOR_565_MACRO(b, d) (b + d - (b >> 5)) 25 26 #define SkDITHER_A32_FOR_4444_MACRO(a, d) (a + 15 - (a >> 4)) 27 #define SkDITHER_R32_FOR_4444_MACRO(r, d) (r + d - (r >> 4)) 28 #define SkDITHER_G32_FOR_4444_MACRO(g, d) (g + d - (g >> 4)) 29 #define SkDITHER_B32_FOR_4444_MACRO(b, d) (b + d - (b >> 4)) 30 31 #ifdef SK_DEBUG 32 inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d) 33 { 34 SkASSERT(d <= SK_DitherValueMax565); 35 SkA32Assert(r); 36 r = SkDITHER_R32_FOR_565_MACRO(r, d); 37 SkA32Assert(r); 38 return r; 39 } 40 inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d) 41 { 42 SkASSERT(d <= SK_DitherValueMax565); 43 SkG32Assert(g); 44 g = SkDITHER_G32_FOR_565_MACRO(g, d); 45 SkG32Assert(g); 46 return g; 47 } 48 inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d) 49 { 50 SkASSERT(d <= SK_DitherValueMax565); 51 SkB32Assert(b); 52 b = SkDITHER_B32_FOR_565_MACRO(b, d); 53 SkB32Assert(b); 54 return b; 55 } 56 #else 57 #define SkDITHER_R32_FOR_565(r, d) SkDITHER_R32_FOR_565_MACRO(r, d) 58 #define SkDITHER_G32_FOR_565(g, d) SkDITHER_G32_FOR_565_MACRO(g, d) 59 #define SkDITHER_B32_FOR_565(b, d) SkDITHER_B32_FOR_565_MACRO(b, d) 60 #endif 61 62 #define SkDITHER_R32To565(r, d) SkR32ToR16(SkDITHER_R32_FOR_565(r, d)) 63 #define SkDITHER_G32To565(g, d) SkG32ToG16(SkDITHER_G32_FOR_565(g, d)) 64 #define SkDITHER_B32To565(b, d) SkB32ToB16(SkDITHER_B32_FOR_565(b, d)) 65 66 #define SkDITHER_A32To4444(a, d) SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d)) 67 #define SkDITHER_R32To4444(r, d) SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d)) 68 #define SkDITHER_G32To4444(g, d) SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d)) 69 #define SkDITHER_B32To4444(b, d) SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d)) 70 71 static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither) 72 { 73 SkASSERT(dither <= SK_DitherValueMax565); 74 75 unsigned sa = SkGetPackedA32(c); 76 dither = SkAlphaMul(dither, SkAlpha255To256(sa)); 77 78 unsigned sr = SkGetPackedR32(c); 79 unsigned sg = SkGetPackedG32(c); 80 unsigned sb = SkGetPackedB32(c); 81 sr = SkDITHER_R32_FOR_565(sr, dither); 82 sg = SkDITHER_G32_FOR_565(sg, dither); 83 sb = SkDITHER_B32_FOR_565(sb, dither); 84 85 return SkPackARGB32(sa, sr, sg, sb); 86 } 87 88 static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither) 89 { 90 SkASSERT(dither <= SK_DitherValueMax565); 91 92 unsigned sr = SkGetPackedR32(c); 93 unsigned sg = SkGetPackedG32(c); 94 unsigned sb = SkGetPackedB32(c); 95 sr = SkDITHER_R32_FOR_565(sr, dither); 96 sg = SkDITHER_G32_FOR_565(sg, dither); 97 sb = SkDITHER_B32_FOR_565(sb, dither); 98 99 return SkPackARGB32(0xFF, sr, sg, sb); 100 } 101 102 static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b, 103 unsigned dither) 104 { 105 SkASSERT(dither <= SK_DitherValueMax565); 106 r = SkDITHER_R32To565(r, dither); 107 g = SkDITHER_G32To565(g, dither); 108 b = SkDITHER_B32To565(b, dither); 109 return SkPackRGB16(r, g, b); 110 } 111 112 static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither) 113 { 114 SkASSERT(dither <= SK_DitherValueMax565); 115 116 unsigned sr = SkGetPackedR32(c); 117 unsigned sg = SkGetPackedG32(c); 118 unsigned sb = SkGetPackedB32(c); 119 sr = SkDITHER_R32To565(sr, dither); 120 sg = SkDITHER_G32To565(sg, dither); 121 sb = SkDITHER_B32To565(sb, dither); 122 123 return SkPackRGB16(sr, sg, sb); 124 } 125 126 static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither) 127 { 128 SkASSERT(dither <= SK_DitherValueMax565); 129 dither = SkAlphaMul(dither, SkAlpha255To256(sa)); 130 131 unsigned sr = SkGetPackedR32(c); 132 unsigned sg = SkGetPackedG32(c); 133 unsigned sb = SkGetPackedB32(c); 134 sr = SkDITHER_R32To565(sr, dither); 135 sg = SkDITHER_G32To565(sg, dither); 136 sb = SkDITHER_B32To565(sb, dither); 137 138 return SkPackRGB16(sr, sg, sb); 139 } 140 141 ///////////////////////// 4444 142 143 static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g, 144 U8CPU b, unsigned dither) 145 { 146 dither = SkAlphaMul(dither, SkAlpha255To256(a)); 147 148 a = SkDITHER_A32To4444(a, dither); 149 r = SkDITHER_R32To4444(r, dither); 150 g = SkDITHER_G32To4444(g, dither); 151 b = SkDITHER_B32To4444(b, dither); 152 153 return SkPackARGB4444(a, r, g, b); 154 } 155 156 static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither) 157 { 158 unsigned a = SkGetPackedA32(c); 159 unsigned r = SkGetPackedR32(c); 160 unsigned g = SkGetPackedG32(c); 161 unsigned b = SkGetPackedB32(c); 162 163 dither = SkAlphaMul(dither, SkAlpha255To256(a)); 164 165 a = SkDITHER_A32To4444(a, dither); 166 r = SkDITHER_R32To4444(r, dither); 167 g = SkDITHER_G32To4444(g, dither); 168 b = SkDITHER_B32To4444(b, dither); 169 170 return SkPackARGB4444(a, r, g, b); 171 } 172 173 // TODO: need dither routines for 565 -> 4444 174 175 // this toggles between a 4x4 and a 1x4 array 176 //#define ENABLE_DITHER_MATRIX_4X4 177 178 #ifdef ENABLE_DITHER_MATRIX_4X4 179 extern const uint8_t gDitherMatrix_4Bit_4X4[4][4]; 180 extern const uint8_t gDitherMatrix_3Bit_4X4[4][4]; 181 182 #define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3] 183 #define DITHER_565_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3] 184 185 #define DITHER_VALUE(x) dither_scan[(x) & 3] 186 #else 187 extern const uint16_t gDitherMatrix_4Bit_16[4]; 188 extern const uint16_t gDitherMatrix_3Bit_16[4]; 189 190 #define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3] 191 #define DITHER_565_SCAN(y) const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3] 192 193 #define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF) 194 #endif 195 196 #define DITHER_INC_X(x) ++(x) 197 198 #endif 199
