| /* |
| * Copyright 2008 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| |
| #ifndef SkDither_DEFINED |
| #define SkDither_DEFINED |
| |
| #include "SkColorPriv.h" |
| |
| #define SK_DitherValueMax4444 15 |
| #define SK_DitherValueMax565 7 |
| |
| /* need to use macros for bit-counts for each component, and then |
| move these into SkColorPriv.h |
| */ |
| |
| #define SkDITHER_R32_FOR_565_MACRO(r, d) (r + d - (r >> 5)) |
| #define SkDITHER_G32_FOR_565_MACRO(g, d) (g + (d >> 1) - (g >> 6)) |
| #define SkDITHER_B32_FOR_565_MACRO(b, d) (b + d - (b >> 5)) |
| |
| #define SkDITHER_A32_FOR_4444_MACRO(a, d) (a + 15 - (a >> 4)) |
| #define SkDITHER_R32_FOR_4444_MACRO(r, d) (r + d - (r >> 4)) |
| #define SkDITHER_G32_FOR_4444_MACRO(g, d) (g + d - (g >> 4)) |
| #define SkDITHER_B32_FOR_4444_MACRO(b, d) (b + d - (b >> 4)) |
| |
| #ifdef SK_DEBUG |
| inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d) |
| { |
| SkASSERT(d <= SK_DitherValueMax565); |
| SkA32Assert(r); |
| r = SkDITHER_R32_FOR_565_MACRO(r, d); |
| SkA32Assert(r); |
| return r; |
| } |
| inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d) |
| { |
| SkASSERT(d <= SK_DitherValueMax565); |
| SkG32Assert(g); |
| g = SkDITHER_G32_FOR_565_MACRO(g, d); |
| SkG32Assert(g); |
| return g; |
| } |
| inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d) |
| { |
| SkASSERT(d <= SK_DitherValueMax565); |
| SkB32Assert(b); |
| b = SkDITHER_B32_FOR_565_MACRO(b, d); |
| SkB32Assert(b); |
| return b; |
| } |
| #else |
| #define SkDITHER_R32_FOR_565(r, d) SkDITHER_R32_FOR_565_MACRO(r, d) |
| #define SkDITHER_G32_FOR_565(g, d) SkDITHER_G32_FOR_565_MACRO(g, d) |
| #define SkDITHER_B32_FOR_565(b, d) SkDITHER_B32_FOR_565_MACRO(b, d) |
| #endif |
| |
| #define SkDITHER_R32To565(r, d) SkR32ToR16(SkDITHER_R32_FOR_565(r, d)) |
| #define SkDITHER_G32To565(g, d) SkG32ToG16(SkDITHER_G32_FOR_565(g, d)) |
| #define SkDITHER_B32To565(b, d) SkB32ToB16(SkDITHER_B32_FOR_565(b, d)) |
| |
| #define SkDITHER_A32To4444(a, d) SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d)) |
| #define SkDITHER_R32To4444(r, d) SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d)) |
| #define SkDITHER_G32To4444(g, d) SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d)) |
| #define SkDITHER_B32To4444(b, d) SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d)) |
| |
| static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither) |
| { |
| SkASSERT(dither <= SK_DitherValueMax565); |
| |
| unsigned sa = SkGetPackedA32(c); |
| dither = SkAlphaMul(dither, SkAlpha255To256(sa)); |
| |
| unsigned sr = SkGetPackedR32(c); |
| unsigned sg = SkGetPackedG32(c); |
| unsigned sb = SkGetPackedB32(c); |
| sr = SkDITHER_R32_FOR_565(sr, dither); |
| sg = SkDITHER_G32_FOR_565(sg, dither); |
| sb = SkDITHER_B32_FOR_565(sb, dither); |
| |
| return SkPackARGB32(sa, sr, sg, sb); |
| } |
| |
| static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither) |
| { |
| SkASSERT(dither <= SK_DitherValueMax565); |
| |
| unsigned sr = SkGetPackedR32(c); |
| unsigned sg = SkGetPackedG32(c); |
| unsigned sb = SkGetPackedB32(c); |
| sr = SkDITHER_R32_FOR_565(sr, dither); |
| sg = SkDITHER_G32_FOR_565(sg, dither); |
| sb = SkDITHER_B32_FOR_565(sb, dither); |
| |
| return SkPackARGB32(0xFF, sr, sg, sb); |
| } |
| |
| static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b, |
| unsigned dither) |
| { |
| SkASSERT(dither <= SK_DitherValueMax565); |
| r = SkDITHER_R32To565(r, dither); |
| g = SkDITHER_G32To565(g, dither); |
| b = SkDITHER_B32To565(b, dither); |
| return SkPackRGB16(r, g, b); |
| } |
| |
| static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither) |
| { |
| SkASSERT(dither <= SK_DitherValueMax565); |
| |
| unsigned sr = SkGetPackedR32(c); |
| unsigned sg = SkGetPackedG32(c); |
| unsigned sb = SkGetPackedB32(c); |
| sr = SkDITHER_R32To565(sr, dither); |
| sg = SkDITHER_G32To565(sg, dither); |
| sb = SkDITHER_B32To565(sb, dither); |
| |
| return SkPackRGB16(sr, sg, sb); |
| } |
| |
| static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither) |
| { |
| SkASSERT(dither <= SK_DitherValueMax565); |
| dither = SkAlphaMul(dither, SkAlpha255To256(sa)); |
| |
| unsigned sr = SkGetPackedR32(c); |
| unsigned sg = SkGetPackedG32(c); |
| unsigned sb = SkGetPackedB32(c); |
| sr = SkDITHER_R32To565(sr, dither); |
| sg = SkDITHER_G32To565(sg, dither); |
| sb = SkDITHER_B32To565(sb, dither); |
| |
| return SkPackRGB16(sr, sg, sb); |
| } |
| |
| ///////////////////////// 4444 |
| |
| static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g, |
| U8CPU b, unsigned dither) |
| { |
| dither = SkAlphaMul(dither, SkAlpha255To256(a)); |
| |
| a = SkDITHER_A32To4444(a, dither); |
| r = SkDITHER_R32To4444(r, dither); |
| g = SkDITHER_G32To4444(g, dither); |
| b = SkDITHER_B32To4444(b, dither); |
| |
| return SkPackARGB4444(a, r, g, b); |
| } |
| |
| static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither) |
| { |
| unsigned a = SkGetPackedA32(c); |
| unsigned r = SkGetPackedR32(c); |
| unsigned g = SkGetPackedG32(c); |
| unsigned b = SkGetPackedB32(c); |
| |
| dither = SkAlphaMul(dither, SkAlpha255To256(a)); |
| |
| a = SkDITHER_A32To4444(a, dither); |
| r = SkDITHER_R32To4444(r, dither); |
| g = SkDITHER_G32To4444(g, dither); |
| b = SkDITHER_B32To4444(b, dither); |
| |
| return SkPackARGB4444(a, r, g, b); |
| } |
| |
| // TODO: need dither routines for 565 -> 4444 |
| |
| // this toggles between a 4x4 and a 1x4 array |
| //#define ENABLE_DITHER_MATRIX_4X4 |
| |
| #ifdef ENABLE_DITHER_MATRIX_4X4 |
| extern const uint8_t gDitherMatrix_4Bit_4X4[4][4]; |
| extern const uint8_t gDitherMatrix_3Bit_4X4[4][4]; |
| |
| #define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3] |
| #define DITHER_565_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3] |
| |
| #define DITHER_VALUE(x) dither_scan[(x) & 3] |
| #else |
| extern const uint16_t gDitherMatrix_4Bit_16[4]; |
| extern const uint16_t gDitherMatrix_3Bit_16[4]; |
| |
| #define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3] |
| #define DITHER_565_SCAN(y) const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3] |
| |
| #define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF) |
| #endif |
| |
| #define DITHER_INC_X(x) ++(x) |
| |
| #endif |