206 lines
6.6 KiB
C
206 lines
6.6 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef SkDither_DEFINED
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#define SkDither_DEFINED
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#include "SkColorPriv.h"
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#define SK_DitherValueMax4444 15
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#define SK_DitherValueMax565 7
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/* need to use macros for bit-counts for each component, and then
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move these into SkColorPriv.h
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*/
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#define SkDITHER_R32_FOR_565_MACRO(r, d) (r + d - (r >> 5))
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#define SkDITHER_G32_FOR_565_MACRO(g, d) (g + (d >> 1) - (g >> 6))
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#define SkDITHER_B32_FOR_565_MACRO(b, d) (b + d - (b >> 5))
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#define SkDITHER_A32_FOR_4444_MACRO(a, d) (a + 15 - (a >> 4))
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#define SkDITHER_R32_FOR_4444_MACRO(r, d) (r + d - (r >> 4))
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#define SkDITHER_G32_FOR_4444_MACRO(g, d) (g + d - (g >> 4))
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#define SkDITHER_B32_FOR_4444_MACRO(b, d) (b + d - (b >> 4))
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#ifdef SK_DEBUG
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inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d)
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{
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SkASSERT(d <= SK_DitherValueMax565);
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SkA32Assert(r);
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r = SkDITHER_R32_FOR_565_MACRO(r, d);
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SkA32Assert(r);
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return r;
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}
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inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d)
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{
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SkASSERT(d <= SK_DitherValueMax565);
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SkG32Assert(g);
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g = SkDITHER_G32_FOR_565_MACRO(g, d);
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SkG32Assert(g);
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return g;
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}
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inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d)
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{
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SkASSERT(d <= SK_DitherValueMax565);
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SkB32Assert(b);
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b = SkDITHER_B32_FOR_565_MACRO(b, d);
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SkB32Assert(b);
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return b;
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}
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#else
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#define SkDITHER_R32_FOR_565(r, d) SkDITHER_R32_FOR_565_MACRO(r, d)
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#define SkDITHER_G32_FOR_565(g, d) SkDITHER_G32_FOR_565_MACRO(g, d)
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#define SkDITHER_B32_FOR_565(b, d) SkDITHER_B32_FOR_565_MACRO(b, d)
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#endif
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#define SkDITHER_R32To565(r, d) SkR32ToR16(SkDITHER_R32_FOR_565(r, d))
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#define SkDITHER_G32To565(g, d) SkG32ToG16(SkDITHER_G32_FOR_565(g, d))
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#define SkDITHER_B32To565(b, d) SkB32ToB16(SkDITHER_B32_FOR_565(b, d))
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#define SkDITHER_A32To4444(a, d) SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d))
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#define SkDITHER_R32To4444(r, d) SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d))
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#define SkDITHER_G32To4444(g, d) SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d))
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#define SkDITHER_B32To4444(b, d) SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d))
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static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither)
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{
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SkASSERT(dither <= SK_DitherValueMax565);
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unsigned sa = SkGetPackedA32(c);
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dither = SkAlphaMul(dither, SkAlpha255To256(sa));
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unsigned sr = SkGetPackedR32(c);
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unsigned sg = SkGetPackedG32(c);
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unsigned sb = SkGetPackedB32(c);
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sr = SkDITHER_R32_FOR_565(sr, dither);
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sg = SkDITHER_G32_FOR_565(sg, dither);
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sb = SkDITHER_B32_FOR_565(sb, dither);
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return SkPackARGB32(sa, sr, sg, sb);
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}
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static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither)
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{
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SkASSERT(dither <= SK_DitherValueMax565);
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unsigned sr = SkGetPackedR32(c);
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unsigned sg = SkGetPackedG32(c);
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unsigned sb = SkGetPackedB32(c);
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sr = SkDITHER_R32_FOR_565(sr, dither);
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sg = SkDITHER_G32_FOR_565(sg, dither);
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sb = SkDITHER_B32_FOR_565(sb, dither);
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return SkPackARGB32(0xFF, sr, sg, sb);
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}
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static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b,
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unsigned dither)
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{
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SkASSERT(dither <= SK_DitherValueMax565);
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r = SkDITHER_R32To565(r, dither);
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g = SkDITHER_G32To565(g, dither);
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b = SkDITHER_B32To565(b, dither);
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return SkPackRGB16(r, g, b);
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}
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static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither)
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{
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SkASSERT(dither <= SK_DitherValueMax565);
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unsigned sr = SkGetPackedR32(c);
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unsigned sg = SkGetPackedG32(c);
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unsigned sb = SkGetPackedB32(c);
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sr = SkDITHER_R32To565(sr, dither);
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sg = SkDITHER_G32To565(sg, dither);
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sb = SkDITHER_B32To565(sb, dither);
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return SkPackRGB16(sr, sg, sb);
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}
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static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither)
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{
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SkASSERT(dither <= SK_DitherValueMax565);
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dither = SkAlphaMul(dither, SkAlpha255To256(sa));
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unsigned sr = SkGetPackedR32(c);
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unsigned sg = SkGetPackedG32(c);
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unsigned sb = SkGetPackedB32(c);
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sr = SkDITHER_R32To565(sr, dither);
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sg = SkDITHER_G32To565(sg, dither);
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sb = SkDITHER_B32To565(sb, dither);
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return SkPackRGB16(sr, sg, sb);
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}
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///////////////////////// 4444
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static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g,
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U8CPU b, unsigned dither)
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{
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dither = SkAlphaMul(dither, SkAlpha255To256(a));
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a = SkDITHER_A32To4444(a, dither);
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r = SkDITHER_R32To4444(r, dither);
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g = SkDITHER_G32To4444(g, dither);
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b = SkDITHER_B32To4444(b, dither);
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return SkPackARGB4444(a, r, g, b);
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}
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static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither)
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{
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unsigned a = SkGetPackedA32(c);
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unsigned r = SkGetPackedR32(c);
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unsigned g = SkGetPackedG32(c);
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unsigned b = SkGetPackedB32(c);
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dither = SkAlphaMul(dither, SkAlpha255To256(a));
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a = SkDITHER_A32To4444(a, dither);
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r = SkDITHER_R32To4444(r, dither);
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g = SkDITHER_G32To4444(g, dither);
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b = SkDITHER_B32To4444(b, dither);
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return SkPackARGB4444(a, r, g, b);
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}
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// TODO: need dither routines for 565 -> 4444
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// this toggles between a 4x4 and a 1x4 array
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//#define ENABLE_DITHER_MATRIX_4X4
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#ifdef ENABLE_DITHER_MATRIX_4X4
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extern const uint8_t gDitherMatrix_4Bit_4X4[4][4];
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extern const uint8_t gDitherMatrix_3Bit_4X4[4][4];
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#define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3]
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#define DITHER_565_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3]
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#define DITHER_VALUE(x) dither_scan[(x) & 3]
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#else
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extern const uint16_t gDitherMatrix_4Bit_16[4];
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extern const uint16_t gDitherMatrix_3Bit_16[4];
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#define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3]
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#define DITHER_565_SCAN(y) const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3]
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#define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF)
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#endif
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#define DITHER_INC_X(x) ++(x)
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#endif
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