1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/core/SkDither.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,198 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2008 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#ifndef SkDither_DEFINED
1.14 +#define SkDither_DEFINED
1.15 +
1.16 +#include "SkColorPriv.h"
1.17 +
1.18 +#define SK_DitherValueMax4444 15
1.19 +#define SK_DitherValueMax565 7
1.20 +
1.21 +/* need to use macros for bit-counts for each component, and then
1.22 + move these into SkColorPriv.h
1.23 +*/
1.24 +
1.25 +#define SkDITHER_R32_FOR_565_MACRO(r, d) (r + d - (r >> 5))
1.26 +#define SkDITHER_G32_FOR_565_MACRO(g, d) (g + (d >> 1) - (g >> 6))
1.27 +#define SkDITHER_B32_FOR_565_MACRO(b, d) (b + d - (b >> 5))
1.28 +
1.29 +#define SkDITHER_A32_FOR_4444_MACRO(a, d) (a + 15 - (a >> 4))
1.30 +#define SkDITHER_R32_FOR_4444_MACRO(r, d) (r + d - (r >> 4))
1.31 +#define SkDITHER_G32_FOR_4444_MACRO(g, d) (g + d - (g >> 4))
1.32 +#define SkDITHER_B32_FOR_4444_MACRO(b, d) (b + d - (b >> 4))
1.33 +
1.34 +#ifdef SK_DEBUG
1.35 + inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d)
1.36 + {
1.37 + SkASSERT(d <= SK_DitherValueMax565);
1.38 + SkA32Assert(r);
1.39 + r = SkDITHER_R32_FOR_565_MACRO(r, d);
1.40 + SkA32Assert(r);
1.41 + return r;
1.42 + }
1.43 + inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d)
1.44 + {
1.45 + SkASSERT(d <= SK_DitherValueMax565);
1.46 + SkG32Assert(g);
1.47 + g = SkDITHER_G32_FOR_565_MACRO(g, d);
1.48 + SkG32Assert(g);
1.49 + return g;
1.50 + }
1.51 + inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d)
1.52 + {
1.53 + SkASSERT(d <= SK_DitherValueMax565);
1.54 + SkB32Assert(b);
1.55 + b = SkDITHER_B32_FOR_565_MACRO(b, d);
1.56 + SkB32Assert(b);
1.57 + return b;
1.58 + }
1.59 +#else
1.60 + #define SkDITHER_R32_FOR_565(r, d) SkDITHER_R32_FOR_565_MACRO(r, d)
1.61 + #define SkDITHER_G32_FOR_565(g, d) SkDITHER_G32_FOR_565_MACRO(g, d)
1.62 + #define SkDITHER_B32_FOR_565(b, d) SkDITHER_B32_FOR_565_MACRO(b, d)
1.63 +#endif
1.64 +
1.65 +#define SkDITHER_R32To565(r, d) SkR32ToR16(SkDITHER_R32_FOR_565(r, d))
1.66 +#define SkDITHER_G32To565(g, d) SkG32ToG16(SkDITHER_G32_FOR_565(g, d))
1.67 +#define SkDITHER_B32To565(b, d) SkB32ToB16(SkDITHER_B32_FOR_565(b, d))
1.68 +
1.69 +#define SkDITHER_A32To4444(a, d) SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d))
1.70 +#define SkDITHER_R32To4444(r, d) SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d))
1.71 +#define SkDITHER_G32To4444(g, d) SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d))
1.72 +#define SkDITHER_B32To4444(b, d) SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d))
1.73 +
1.74 +static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither)
1.75 +{
1.76 + SkASSERT(dither <= SK_DitherValueMax565);
1.77 +
1.78 + unsigned sa = SkGetPackedA32(c);
1.79 + dither = SkAlphaMul(dither, SkAlpha255To256(sa));
1.80 +
1.81 + unsigned sr = SkGetPackedR32(c);
1.82 + unsigned sg = SkGetPackedG32(c);
1.83 + unsigned sb = SkGetPackedB32(c);
1.84 + sr = SkDITHER_R32_FOR_565(sr, dither);
1.85 + sg = SkDITHER_G32_FOR_565(sg, dither);
1.86 + sb = SkDITHER_B32_FOR_565(sb, dither);
1.87 +
1.88 + return SkPackARGB32(sa, sr, sg, sb);
1.89 +}
1.90 +
1.91 +static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither)
1.92 +{
1.93 + SkASSERT(dither <= SK_DitherValueMax565);
1.94 +
1.95 + unsigned sr = SkGetPackedR32(c);
1.96 + unsigned sg = SkGetPackedG32(c);
1.97 + unsigned sb = SkGetPackedB32(c);
1.98 + sr = SkDITHER_R32_FOR_565(sr, dither);
1.99 + sg = SkDITHER_G32_FOR_565(sg, dither);
1.100 + sb = SkDITHER_B32_FOR_565(sb, dither);
1.101 +
1.102 + return SkPackARGB32(0xFF, sr, sg, sb);
1.103 +}
1.104 +
1.105 +static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b,
1.106 + unsigned dither)
1.107 +{
1.108 + SkASSERT(dither <= SK_DitherValueMax565);
1.109 + r = SkDITHER_R32To565(r, dither);
1.110 + g = SkDITHER_G32To565(g, dither);
1.111 + b = SkDITHER_B32To565(b, dither);
1.112 + return SkPackRGB16(r, g, b);
1.113 +}
1.114 +
1.115 +static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither)
1.116 +{
1.117 + SkASSERT(dither <= SK_DitherValueMax565);
1.118 +
1.119 + unsigned sr = SkGetPackedR32(c);
1.120 + unsigned sg = SkGetPackedG32(c);
1.121 + unsigned sb = SkGetPackedB32(c);
1.122 + sr = SkDITHER_R32To565(sr, dither);
1.123 + sg = SkDITHER_G32To565(sg, dither);
1.124 + sb = SkDITHER_B32To565(sb, dither);
1.125 +
1.126 + return SkPackRGB16(sr, sg, sb);
1.127 +}
1.128 +
1.129 +static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither)
1.130 +{
1.131 + SkASSERT(dither <= SK_DitherValueMax565);
1.132 + dither = SkAlphaMul(dither, SkAlpha255To256(sa));
1.133 +
1.134 + unsigned sr = SkGetPackedR32(c);
1.135 + unsigned sg = SkGetPackedG32(c);
1.136 + unsigned sb = SkGetPackedB32(c);
1.137 + sr = SkDITHER_R32To565(sr, dither);
1.138 + sg = SkDITHER_G32To565(sg, dither);
1.139 + sb = SkDITHER_B32To565(sb, dither);
1.140 +
1.141 + return SkPackRGB16(sr, sg, sb);
1.142 +}
1.143 +
1.144 +///////////////////////// 4444
1.145 +
1.146 +static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g,
1.147 + U8CPU b, unsigned dither)
1.148 +{
1.149 + dither = SkAlphaMul(dither, SkAlpha255To256(a));
1.150 +
1.151 + a = SkDITHER_A32To4444(a, dither);
1.152 + r = SkDITHER_R32To4444(r, dither);
1.153 + g = SkDITHER_G32To4444(g, dither);
1.154 + b = SkDITHER_B32To4444(b, dither);
1.155 +
1.156 + return SkPackARGB4444(a, r, g, b);
1.157 +}
1.158 +
1.159 +static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither)
1.160 +{
1.161 + unsigned a = SkGetPackedA32(c);
1.162 + unsigned r = SkGetPackedR32(c);
1.163 + unsigned g = SkGetPackedG32(c);
1.164 + unsigned b = SkGetPackedB32(c);
1.165 +
1.166 + dither = SkAlphaMul(dither, SkAlpha255To256(a));
1.167 +
1.168 + a = SkDITHER_A32To4444(a, dither);
1.169 + r = SkDITHER_R32To4444(r, dither);
1.170 + g = SkDITHER_G32To4444(g, dither);
1.171 + b = SkDITHER_B32To4444(b, dither);
1.172 +
1.173 + return SkPackARGB4444(a, r, g, b);
1.174 +}
1.175 +
1.176 +// TODO: need dither routines for 565 -> 4444
1.177 +
1.178 +// this toggles between a 4x4 and a 1x4 array
1.179 +//#define ENABLE_DITHER_MATRIX_4X4
1.180 +
1.181 +#ifdef ENABLE_DITHER_MATRIX_4X4
1.182 + extern const uint8_t gDitherMatrix_4Bit_4X4[4][4];
1.183 + extern const uint8_t gDitherMatrix_3Bit_4X4[4][4];
1.184 +
1.185 + #define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3]
1.186 + #define DITHER_565_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3]
1.187 +
1.188 + #define DITHER_VALUE(x) dither_scan[(x) & 3]
1.189 +#else
1.190 + extern const uint16_t gDitherMatrix_4Bit_16[4];
1.191 + extern const uint16_t gDitherMatrix_3Bit_16[4];
1.192 +
1.193 + #define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3]
1.194 + #define DITHER_565_SCAN(y) const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3]
1.195 +
1.196 + #define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF)
1.197 +#endif
1.198 +
1.199 +#define DITHER_INC_X(x) ++(x)
1.200 +
1.201 +#endif
