1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SkDither_DEFINED 18 #define SkDither_DEFINED 19 20 #include "SkColorPriv.h" 21 22 #define SK_DitherValueMax4444 15 23 #define SK_DitherValueMax565 7 24 25 /* need to use macros for bit-counts for each component, and then 26 move these into SkColorPriv.h 27 */ 28 29 #define SkDITHER_R32_FOR_565_MACRO(r, d) (r + d - (r >> 5)) 30 #define SkDITHER_G32_FOR_565_MACRO(g, d) (g + (d >> 1) - (g >> 6)) 31 #define SkDITHER_B32_FOR_565_MACRO(b, d) (b + d - (b >> 5)) 32 33 #define SkDITHER_A32_FOR_4444_MACRO(a, d) (a + 15 - (a >> 4)) 34 #define SkDITHER_R32_FOR_4444_MACRO(r, d) (r + d - (r >> 4)) 35 #define SkDITHER_G32_FOR_4444_MACRO(g, d) (g + d - (g >> 4)) 36 #define SkDITHER_B32_FOR_4444_MACRO(b, d) (b + d - (b >> 4)) 37 38 #ifdef SK_DEBUG 39 inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d) 40 { 41 SkASSERT(d <= SK_DitherValueMax565); 42 SkA32Assert(r); 43 r = SkDITHER_R32_FOR_565_MACRO(r, d); 44 SkA32Assert(r); 45 return r; 46 } 47 inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d) 48 { 49 SkASSERT(d <= SK_DitherValueMax565); 50 SkG32Assert(g); 51 g = SkDITHER_G32_FOR_565_MACRO(g, d); 52 SkG32Assert(g); 53 return g; 54 } 55 inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d) 56 { 57 SkASSERT(d <= SK_DitherValueMax565); 58 SkB32Assert(b); 59 b = SkDITHER_B32_FOR_565_MACRO(b, d); 60 SkB32Assert(b); 61 return b; 62 } 63 #else 64 #define SkDITHER_R32_FOR_565(r, d) SkDITHER_R32_FOR_565_MACRO(r, d) 65 #define SkDITHER_G32_FOR_565(g, d) SkDITHER_G32_FOR_565_MACRO(g, d) 66 #define SkDITHER_B32_FOR_565(b, d) SkDITHER_B32_FOR_565_MACRO(b, d) 67 #endif 68 69 #define SkDITHER_R32To565(r, d) SkR32ToR16(SkDITHER_R32_FOR_565(r, d)) 70 #define SkDITHER_G32To565(g, d) SkG32ToG16(SkDITHER_G32_FOR_565(g, d)) 71 #define SkDITHER_B32To565(b, d) SkB32ToB16(SkDITHER_B32_FOR_565(b, d)) 72 73 #define SkDITHER_A32To4444(a, d) SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d)) 74 #define SkDITHER_R32To4444(r, d) SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d)) 75 #define SkDITHER_G32To4444(g, d) SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d)) 76 #define SkDITHER_B32To4444(b, d) SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d)) 77 78 static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither) 79 { 80 SkASSERT(dither <= SK_DitherValueMax565); 81 82 unsigned sa = SkGetPackedA32(c); 83 dither = SkAlphaMul(dither, SkAlpha255To256(sa)); 84 85 unsigned sr = SkGetPackedR32(c); 86 unsigned sg = SkGetPackedG32(c); 87 unsigned sb = SkGetPackedB32(c); 88 sr = SkDITHER_R32_FOR_565(sr, dither); 89 sg = SkDITHER_G32_FOR_565(sg, dither); 90 sb = SkDITHER_B32_FOR_565(sb, dither); 91 92 return SkPackARGB32(sa, sr, sg, sb); 93 } 94 95 static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither) 96 { 97 SkASSERT(dither <= SK_DitherValueMax565); 98 99 unsigned sr = SkGetPackedR32(c); 100 unsigned sg = SkGetPackedG32(c); 101 unsigned sb = SkGetPackedB32(c); 102 sr = SkDITHER_R32_FOR_565(sr, dither); 103 sg = SkDITHER_G32_FOR_565(sg, dither); 104 sb = SkDITHER_B32_FOR_565(sb, dither); 105 106 return SkPackARGB32(0xFF, sr, sg, sb); 107 } 108 109 static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b, 110 unsigned dither) 111 { 112 SkASSERT(dither <= SK_DitherValueMax565); 113 r = SkDITHER_R32To565(r, dither); 114 g = SkDITHER_G32To565(g, dither); 115 b = SkDITHER_B32To565(b, dither); 116 return SkPackRGB16(r, g, b); 117 } 118 119 static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither) 120 { 121 SkASSERT(dither <= SK_DitherValueMax565); 122 123 unsigned sr = SkGetPackedR32(c); 124 unsigned sg = SkGetPackedG32(c); 125 unsigned sb = SkGetPackedB32(c); 126 sr = SkDITHER_R32To565(sr, dither); 127 sg = SkDITHER_G32To565(sg, dither); 128 sb = SkDITHER_B32To565(sb, dither); 129 130 return SkPackRGB16(sr, sg, sb); 131 } 132 133 static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither) 134 { 135 SkASSERT(dither <= SK_DitherValueMax565); 136 dither = SkAlphaMul(dither, SkAlpha255To256(sa)); 137 138 unsigned sr = SkGetPackedR32(c); 139 unsigned sg = SkGetPackedG32(c); 140 unsigned sb = SkGetPackedB32(c); 141 sr = SkDITHER_R32To565(sr, dither); 142 sg = SkDITHER_G32To565(sg, dither); 143 sb = SkDITHER_B32To565(sb, dither); 144 145 return SkPackRGB16(sr, sg, sb); 146 } 147 148 ///////////////////////// 4444 149 150 static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g, 151 U8CPU b, unsigned dither) 152 { 153 dither = SkAlphaMul(dither, SkAlpha255To256(a)); 154 155 a = SkDITHER_A32To4444(a, dither); 156 r = SkDITHER_R32To4444(r, dither); 157 g = SkDITHER_G32To4444(g, dither); 158 b = SkDITHER_B32To4444(b, dither); 159 160 return SkPackARGB4444(a, r, g, b); 161 } 162 163 static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither) 164 { 165 unsigned a = SkGetPackedA32(c); 166 unsigned r = SkGetPackedR32(c); 167 unsigned g = SkGetPackedG32(c); 168 unsigned b = SkGetPackedB32(c); 169 170 dither = SkAlphaMul(dither, SkAlpha255To256(a)); 171 172 a = SkDITHER_A32To4444(a, dither); 173 r = SkDITHER_R32To4444(r, dither); 174 g = SkDITHER_G32To4444(g, dither); 175 b = SkDITHER_B32To4444(b, dither); 176 177 return SkPackARGB4444(a, r, g, b); 178 } 179 180 // TODO: need dither routines for 565 -> 4444 181 182 // this toggles between a 4x4 and a 1x4 array 183 //#define ENABLE_DITHER_MATRIX_4X4 184 185 #ifdef ENABLE_DITHER_MATRIX_4X4 186 extern const uint8_t gDitherMatrix_4Bit_4X4[4][4]; 187 extern const uint8_t gDitherMatrix_3Bit_4X4[4][4]; 188 189 #define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3] 190 #define DITHER_565_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3] 191 192 #define DITHER_VALUE(x) dither_scan[(x) & 3] 193 #else 194 extern const uint16_t gDitherMatrix_4Bit_16[4]; 195 extern const uint16_t gDitherMatrix_3Bit_16[4]; 196 197 #define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3] 198 #define DITHER_565_SCAN(y) const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3] 199 200 #define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF) 201 #endif 202 203 #define DITHER_INC_X(x) ++(x) 204 205 #endif 206
