/*
* 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