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Diffstat (limited to 'src/core/SkColorData.h')
| -rw-r--r-- | src/core/SkColorData.h | 1027 |
1 files changed, 1027 insertions, 0 deletions
diff --git a/src/core/SkColorData.h b/src/core/SkColorData.h new file mode 100644 index 0000000000..a6aa8c8df4 --- /dev/null +++ b/src/core/SkColorData.h @@ -0,0 +1,1027 @@ +/* + * Copyright 2006 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 SkColorData_DEFINED +#define SkColorData_DEFINED + +// turn this own for extra debug checking when blending onto 565 +#ifdef SK_DEBUG + #define CHECK_FOR_565_OVERFLOW +#endif + +#include "SkColor.h" +#include "SkColorPriv.h" +#include "SkMath.h" + +////////////////////////////////////////////////////////////////////////////// + +#define SkASSERT_IS_BYTE(x) SkASSERT(0 == ((x) & ~0xFF)) + +/* + * Skia's 32bit backend only supports 1 sizzle order at a time (compile-time). + * This is specified by 4 defines SK_A32_SHIFT, SK_R32_SHIFT, ... for G and B. + * + * For easier compatibility with Skia's GPU backend, we further restrict these + * to either (in memory-byte-order) RGBA or BGRA. Note that this "order" does + * not directly correspond to the same shift-order, since we have to take endianess + * into account. + * + * Here we enforce this constraint. + */ + +#ifdef SK_CPU_BENDIAN + #define SK_RGBA_R32_SHIFT 24 + #define SK_RGBA_G32_SHIFT 16 + #define SK_RGBA_B32_SHIFT 8 + #define SK_RGBA_A32_SHIFT 0 + + #define SK_BGRA_B32_SHIFT 24 + #define SK_BGRA_G32_SHIFT 16 + #define SK_BGRA_R32_SHIFT 8 + #define SK_BGRA_A32_SHIFT 0 +#else + #define SK_RGBA_R32_SHIFT 0 + #define SK_RGBA_G32_SHIFT 8 + #define SK_RGBA_B32_SHIFT 16 + #define SK_RGBA_A32_SHIFT 24 + + #define SK_BGRA_B32_SHIFT 0 + #define SK_BGRA_G32_SHIFT 8 + #define SK_BGRA_R32_SHIFT 16 + #define SK_BGRA_A32_SHIFT 24 +#endif + +#if defined(SK_PMCOLOR_IS_RGBA) && defined(SK_PMCOLOR_IS_BGRA) + #error "can't define PMCOLOR to be RGBA and BGRA" +#endif + +#define LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_RGBA \ + (SK_A32_SHIFT == SK_RGBA_A32_SHIFT && \ + SK_R32_SHIFT == SK_RGBA_R32_SHIFT && \ + SK_G32_SHIFT == SK_RGBA_G32_SHIFT && \ + SK_B32_SHIFT == SK_RGBA_B32_SHIFT) + +#define LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_BGRA \ + (SK_A32_SHIFT == SK_BGRA_A32_SHIFT && \ + SK_R32_SHIFT == SK_BGRA_R32_SHIFT && \ + SK_G32_SHIFT == SK_BGRA_G32_SHIFT && \ + SK_B32_SHIFT == SK_BGRA_B32_SHIFT) + + +#define SK_A_INDEX (SK_A32_SHIFT/8) +#define SK_R_INDEX (SK_R32_SHIFT/8) +#define SK_G_INDEX (SK_G32_SHIFT/8) +#define SK_B_INDEX (SK_B32_SHIFT/8) + +#if defined(SK_PMCOLOR_IS_RGBA) && !LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_RGBA + #error "SK_PMCOLOR_IS_RGBA does not match SK_*32_SHIFT values" +#endif + +#if defined(SK_PMCOLOR_IS_BGRA) && !LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_BGRA + #error "SK_PMCOLOR_IS_BGRA does not match SK_*32_SHIFT values" +#endif + +#if !defined(SK_PMCOLOR_IS_RGBA) && !defined(SK_PMCOLOR_IS_BGRA) + // deduce which to define from the _SHIFT defines + + #if LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_RGBA + #define SK_PMCOLOR_IS_RGBA + #elif LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_BGRA + #define SK_PMCOLOR_IS_BGRA + #else + #error "need 32bit packing to be either RGBA or BGRA" + #endif +#endif + +// hide these now that we're done +#undef LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_RGBA +#undef LOCAL_PMCOLOR_SHIFTS_EQUIVALENT_TO_BGRA + +////////////////////////////////////////////////////////////////////////////// + +// Reverse the bytes coorsponding to RED and BLUE in a packed pixels. Note the +// pair of them are in the same 2 slots in both RGBA and BGRA, thus there is +// no need to pass in the colortype to this function. +static inline uint32_t SkSwizzle_RB(uint32_t c) { + static const uint32_t kRBMask = (0xFF << SK_R32_SHIFT) | (0xFF << SK_B32_SHIFT); + + unsigned c0 = (c >> SK_R32_SHIFT) & 0xFF; + unsigned c1 = (c >> SK_B32_SHIFT) & 0xFF; + return (c & ~kRBMask) | (c0 << SK_B32_SHIFT) | (c1 << SK_R32_SHIFT); +} + +static inline uint32_t SkPackARGB_as_RGBA(U8CPU a, U8CPU r, U8CPU g, U8CPU b) { + SkASSERT_IS_BYTE(a); + SkASSERT_IS_BYTE(r); + SkASSERT_IS_BYTE(g); + SkASSERT_IS_BYTE(b); + return (a << SK_RGBA_A32_SHIFT) | (r << SK_RGBA_R32_SHIFT) | + (g << SK_RGBA_G32_SHIFT) | (b << SK_RGBA_B32_SHIFT); +} + +static inline uint32_t SkPackARGB_as_BGRA(U8CPU a, U8CPU r, U8CPU g, U8CPU b) { + SkASSERT_IS_BYTE(a); + SkASSERT_IS_BYTE(r); + SkASSERT_IS_BYTE(g); + SkASSERT_IS_BYTE(b); + return (a << SK_BGRA_A32_SHIFT) | (r << SK_BGRA_R32_SHIFT) | + (g << SK_BGRA_G32_SHIFT) | (b << SK_BGRA_B32_SHIFT); +} + +static inline SkPMColor SkSwizzle_RGBA_to_PMColor(uint32_t c) { +#ifdef SK_PMCOLOR_IS_RGBA + return c; +#else + return SkSwizzle_RB(c); +#endif +} + +static inline SkPMColor SkSwizzle_BGRA_to_PMColor(uint32_t c) { +#ifdef SK_PMCOLOR_IS_BGRA + return c; +#else + return SkSwizzle_RB(c); +#endif +} + +////////////////////////////////////////////////////////////////////////////// + +///@{ +/** See ITU-R Recommendation BT.709 at http://www.itu.int/rec/R-REC-BT.709/ .*/ +#define SK_ITU_BT709_LUM_COEFF_R (0.2126f) +#define SK_ITU_BT709_LUM_COEFF_G (0.7152f) +#define SK_ITU_BT709_LUM_COEFF_B (0.0722f) +///@} + +///@{ +/** A float value which specifies this channel's contribution to luminance. */ +#define SK_LUM_COEFF_R SK_ITU_BT709_LUM_COEFF_R +#define SK_LUM_COEFF_G SK_ITU_BT709_LUM_COEFF_G +#define SK_LUM_COEFF_B SK_ITU_BT709_LUM_COEFF_B +///@} + +/** Computes the luminance from the given r, g, and b in accordance with + SK_LUM_COEFF_X. For correct results, r, g, and b should be in linear space. +*/ +static inline U8CPU SkComputeLuminance(U8CPU r, U8CPU g, U8CPU b) { + //The following is + //r * SK_LUM_COEFF_R + g * SK_LUM_COEFF_G + b * SK_LUM_COEFF_B + //with SK_LUM_COEFF_X in 1.8 fixed point (rounding adjusted to sum to 256). + return (r * 54 + g * 183 + b * 19) >> 8; +} + +/** + * Turn a 0..255 value into a 0..256 value, rounding up if the value is >= 0x80. + * This is slightly more accurate than SkAlpha255To256. + */ +static inline unsigned Sk255To256(U8CPU value) { + SkASSERT(SkToU8(value) == value); + return value + (value >> 7); +} + +/** Multiplify value by 0..256, and shift the result down 8 + (i.e. return (value * alpha256) >> 8) + */ +#define SkAlphaMul(value, alpha256) (((value) * (alpha256)) >> 8) + +/** Calculates 256 - (value * alpha256) / 255 in range [0,256], + * for [0,255] value and [0,256] alpha256. + */ +static inline U16CPU SkAlphaMulInv256(U16CPU value, U16CPU alpha256) { + unsigned prod = 0xFFFF - value * alpha256; + return (prod + (prod >> 8)) >> 8; +} + +// The caller may want negative values, so keep all params signed (int) +// so we don't accidentally slip into unsigned math and lose the sign +// extension when we shift (in SkAlphaMul) +static inline int SkAlphaBlend(int src, int dst, int scale256) { + SkASSERT((unsigned)scale256 <= 256); + return dst + SkAlphaMul(src - dst, scale256); +} + +/** + * Returns (src * alpha + dst * (255 - alpha)) / 255 + * + * This is more accurate than SkAlphaBlend, but slightly slower + */ +static inline int SkAlphaBlend255(S16CPU src, S16CPU dst, U8CPU alpha) { + SkASSERT((int16_t)src == src); + SkASSERT((int16_t)dst == dst); + SkASSERT((uint8_t)alpha == alpha); + + int prod = (src - dst) * alpha + 128; + prod = (prod + (prod >> 8)) >> 8; + return dst + prod; +} + +static inline U8CPU SkUnitScalarClampToByte(SkScalar x) { + return static_cast<U8CPU>(SkScalarPin(x, 0, 1) * 255 + 0.5); +} + +#define SK_R16_BITS 5 +#define SK_G16_BITS 6 +#define SK_B16_BITS 5 + +#define SK_R16_SHIFT (SK_B16_BITS + SK_G16_BITS) +#define SK_G16_SHIFT (SK_B16_BITS) +#define SK_B16_SHIFT 0 + +#define SK_R16_MASK ((1 << SK_R16_BITS) - 1) +#define SK_G16_MASK ((1 << SK_G16_BITS) - 1) +#define SK_B16_MASK ((1 << SK_B16_BITS) - 1) + +#define SkGetPackedR16(color) (((unsigned)(color) >> SK_R16_SHIFT) & SK_R16_MASK) +#define SkGetPackedG16(color) (((unsigned)(color) >> SK_G16_SHIFT) & SK_G16_MASK) +#define SkGetPackedB16(color) (((unsigned)(color) >> SK_B16_SHIFT) & SK_B16_MASK) + +#define SkR16Assert(r) SkASSERT((unsigned)(r) <= SK_R16_MASK) +#define SkG16Assert(g) SkASSERT((unsigned)(g) <= SK_G16_MASK) +#define SkB16Assert(b) SkASSERT((unsigned)(b) <= SK_B16_MASK) + +static inline uint16_t SkPackRGB16(unsigned r, unsigned g, unsigned b) { + SkASSERT(r <= SK_R16_MASK); + SkASSERT(g <= SK_G16_MASK); + SkASSERT(b <= SK_B16_MASK); + + return SkToU16((r << SK_R16_SHIFT) | (g << SK_G16_SHIFT) | (b << SK_B16_SHIFT)); +} + +#define SK_R16_MASK_IN_PLACE (SK_R16_MASK << SK_R16_SHIFT) +#define SK_G16_MASK_IN_PLACE (SK_G16_MASK << SK_G16_SHIFT) +#define SK_B16_MASK_IN_PLACE (SK_B16_MASK << SK_B16_SHIFT) + +/** Expand the 16bit color into a 32bit value that can be scaled all at once + by a value up to 32. Used in conjunction with SkCompact_rgb_16. +*/ +static inline uint32_t SkExpand_rgb_16(U16CPU c) { + SkASSERT(c == (uint16_t)c); + + return ((c & SK_G16_MASK_IN_PLACE) << 16) | (c & ~SK_G16_MASK_IN_PLACE); +} + +/** Compress an expanded value (from SkExpand_rgb_16) back down to a 16bit + color value. The computation yields only 16bits of valid data, but we claim + to return 32bits, so that the compiler won't generate extra instructions to + "clean" the top 16bits. However, the top 16 can contain garbage, so it is + up to the caller to safely ignore them. +*/ +static inline U16CPU SkCompact_rgb_16(uint32_t c) { + return ((c >> 16) & SK_G16_MASK_IN_PLACE) | (c & ~SK_G16_MASK_IN_PLACE); +} + +/** Scale the 16bit color value by the 0..256 scale parameter. + The computation yields only 16bits of valid data, but we claim + to return 32bits, so that the compiler won't generate extra instructions to + "clean" the top 16bits. +*/ +static inline U16CPU SkAlphaMulRGB16(U16CPU c, unsigned scale) { + return SkCompact_rgb_16(SkExpand_rgb_16(c) * (scale >> 3) >> 5); +} + +// this helper explicitly returns a clean 16bit value (but slower) +#define SkAlphaMulRGB16_ToU16(c, s) (uint16_t)SkAlphaMulRGB16(c, s) + +/** Blend pre-expanded RGB32 with 16bit color value by the 0..32 scale parameter. + The computation yields only 16bits of valid data, but we claim to return + 32bits, so that the compiler won't generate extra instructions to "clean" + the top 16bits. +*/ +static inline U16CPU SkBlend32_RGB16(uint32_t src_expand, uint16_t dst, unsigned scale) { + uint32_t dst_expand = SkExpand_rgb_16(dst) * scale; + return SkCompact_rgb_16((src_expand + dst_expand) >> 5); +} + +/** Blend src and dst 16bit colors by the 0..256 scale parameter. + The computation yields only 16bits of valid data, but we claim + to return 32bits, so that the compiler won't generate extra instructions to + "clean" the top 16bits. +*/ +static inline U16CPU SkBlendRGB16(U16CPU src, U16CPU dst, int srcScale) { + SkASSERT((unsigned)srcScale <= 256); + + srcScale >>= 3; + + uint32_t src32 = SkExpand_rgb_16(src); + uint32_t dst32 = SkExpand_rgb_16(dst); + return SkCompact_rgb_16(dst32 + ((src32 - dst32) * srcScale >> 5)); +} + +static inline void SkBlendRGB16(const uint16_t src[], uint16_t dst[], + int srcScale, int count) { + SkASSERT(count > 0); + SkASSERT((unsigned)srcScale <= 256); + + srcScale >>= 3; + + do { + uint32_t src32 = SkExpand_rgb_16(*src++); + uint32_t dst32 = SkExpand_rgb_16(*dst); + *dst++ = static_cast<uint16_t>( + SkCompact_rgb_16(dst32 + ((src32 - dst32) * srcScale >> 5))); + } while (--count > 0); +} + +#ifdef SK_DEBUG + static inline U16CPU SkRGB16Add(U16CPU a, U16CPU b) { + SkASSERT(SkGetPackedR16(a) + SkGetPackedR16(b) <= SK_R16_MASK); + SkASSERT(SkGetPackedG16(a) + SkGetPackedG16(b) <= SK_G16_MASK); + SkASSERT(SkGetPackedB16(a) + SkGetPackedB16(b) <= SK_B16_MASK); + + return a + b; + } +#else + #define SkRGB16Add(a, b) ((a) + (b)) +#endif + +/////////////////////////////////////////////////////////////////////////////// + +#define SK_R32_BITS 8 +#define SK_G32_BITS 8 +#define SK_B32_BITS 8 + +#define SK_R32_MASK ((1 << SK_R32_BITS) - 1) +#define SK_G32_MASK ((1 << SK_G32_BITS) - 1) +#define SK_B32_MASK ((1 << SK_B32_BITS) - 1) + +#define SkR32Assert(r) SkASSERT((unsigned)(r) <= SK_R32_MASK) +#define SkG32Assert(g) SkASSERT((unsigned)(g) <= SK_G32_MASK) +#define SkB32Assert(b) SkASSERT((unsigned)(b) <= SK_B32_MASK) + +#ifdef SK_DEBUG + #define SkPMColorAssert(color_value) \ + do { \ + SkPMColor pm_color_value = (color_value); \ + uint32_t alpha_color_value = SkGetPackedA32(pm_color_value); \ + SkA32Assert(alpha_color_value); \ + SkASSERT(SkGetPackedR32(pm_color_value) <= alpha_color_value); \ + SkASSERT(SkGetPackedG32(pm_color_value) <= alpha_color_value); \ + SkASSERT(SkGetPackedB32(pm_color_value) <= alpha_color_value); \ + } while (false) +#else + #define SkPMColorAssert(c) +#endif + +static inline bool SkPMColorValid(SkPMColor c) { + auto a = SkGetPackedA32(c); + bool valid = a <= SK_A32_MASK + && SkGetPackedR32(c) <= a + && SkGetPackedG32(c) <= a + && SkGetPackedB32(c) <= a; + if (valid) { + SkPMColorAssert(c); // Make sure we're consistent when it counts. + } + return valid; +} + +static inline uint32_t SkPackPMColor_as_RGBA(SkPMColor c) { + return SkPackARGB_as_RGBA(SkGetPackedA32(c), SkGetPackedR32(c), + SkGetPackedG32(c), SkGetPackedB32(c)); +} + +static inline uint32_t SkPackPMColor_as_BGRA(SkPMColor c) { + return SkPackARGB_as_BGRA(SkGetPackedA32(c), SkGetPackedR32(c), + SkGetPackedG32(c), SkGetPackedB32(c)); +} + +/** + * Abstract 4-byte interpolation, implemented on top of SkPMColor + * utility functions. Third parameter controls blending of the first two: + * (src, dst, 0) returns dst + * (src, dst, 0xFF) returns src + * srcWeight is [0..256], unlike SkFourByteInterp which takes [0..255] + */ +static inline SkPMColor SkFourByteInterp256(SkPMColor src, SkPMColor dst, + unsigned scale) { + unsigned a = SkAlphaBlend(SkGetPackedA32(src), SkGetPackedA32(dst), scale); + unsigned r = SkAlphaBlend(SkGetPackedR32(src), SkGetPackedR32(dst), scale); + unsigned g = SkAlphaBlend(SkGetPackedG32(src), SkGetPackedG32(dst), scale); + unsigned b = SkAlphaBlend(SkGetPackedB32(src), SkGetPackedB32(dst), scale); + + return SkPackARGB32(a, r, g, b); +} + +/** + * Abstract 4-byte interpolation, implemented on top of SkPMColor + * utility functions. Third parameter controls blending of the first two: + * (src, dst, 0) returns dst + * (src, dst, 0xFF) returns src + */ +static inline SkPMColor SkFourByteInterp(SkPMColor src, SkPMColor dst, + U8CPU srcWeight) { + unsigned scale = SkAlpha255To256(srcWeight); + return SkFourByteInterp256(src, dst, scale); +} + +/** + * 0xAARRGGBB -> 0x00AA00GG, 0x00RR00BB + */ +static inline void SkSplay(uint32_t color, uint32_t* ag, uint32_t* rb) { + const uint32_t mask = 0x00FF00FF; + *ag = (color >> 8) & mask; + *rb = color & mask; +} + +/** + * 0xAARRGGBB -> 0x00AA00GG00RR00BB + * (note, ARGB -> AGRB) + */ +static inline uint64_t SkSplay(uint32_t color) { + const uint32_t mask = 0x00FF00FF; + uint64_t agrb = (color >> 8) & mask; // 0x0000000000AA00GG + agrb <<= 32; // 0x00AA00GG00000000 + agrb |= color & mask; // 0x00AA00GG00RR00BB + return agrb; +} + +/** + * 0xAAxxGGxx, 0xRRxxBBxx-> 0xAARRGGBB + */ +static inline uint32_t SkUnsplay(uint32_t ag, uint32_t rb) { + const uint32_t mask = 0xFF00FF00; + return (ag & mask) | ((rb & mask) >> 8); +} + +/** + * 0xAAxxGGxxRRxxBBxx -> 0xAARRGGBB + * (note, AGRB -> ARGB) + */ +static inline uint32_t SkUnsplay(uint64_t agrb) { + const uint32_t mask = 0xFF00FF00; + return SkPMColor( + ((agrb & mask) >> 8) | // 0x00RR00BB + ((agrb >> 32) & mask)); // 0xAARRGGBB +} + +static inline SkPMColor SkFastFourByteInterp256_32(SkPMColor src, SkPMColor dst, unsigned scale) { + SkASSERT(scale <= 256); + + // Two 8-bit blends per two 32-bit registers, with space to make sure the math doesn't collide. + uint32_t src_ag, src_rb, dst_ag, dst_rb; + SkSplay(src, &src_ag, &src_rb); + SkSplay(dst, &dst_ag, &dst_rb); + + const uint32_t ret_ag = src_ag * scale + (256 - scale) * dst_ag; + const uint32_t ret_rb = src_rb * scale + (256 - scale) * dst_rb; + + return SkUnsplay(ret_ag, ret_rb); +} + +static inline SkPMColor SkFastFourByteInterp256_64(SkPMColor src, SkPMColor dst, unsigned scale) { + SkASSERT(scale <= 256); + // Four 8-bit blends in one 64-bit register, with space to make sure the math doesn't collide. + return SkUnsplay(SkSplay(src) * scale + (256-scale) * SkSplay(dst)); +} + +// TODO(mtklein): Replace slow versions with fast versions, using scale + (scale>>7) everywhere. + +/** + * Same as SkFourByteInterp256, but faster. + */ +static inline SkPMColor SkFastFourByteInterp256(SkPMColor src, SkPMColor dst, unsigned scale) { + // On a 64-bit machine, _64 is about 10% faster than _32, but ~40% slower on a 32-bit machine. + if (sizeof(void*) == 4) { + return SkFastFourByteInterp256_32(src, dst, scale); + } else { + return SkFastFourByteInterp256_64(src, dst, scale); + } +} + +/** + * Nearly the same as SkFourByteInterp, but faster and a touch more accurate, due to better + * srcWeight scaling to [0, 256]. + */ +static inline SkPMColor SkFastFourByteInterp(SkPMColor src, + SkPMColor dst, + U8CPU srcWeight) { + SkASSERT(srcWeight <= 255); + // scale = srcWeight + (srcWeight >> 7) is more accurate than + // scale = srcWeight + 1, but 7% slower + return SkFastFourByteInterp256(src, dst, srcWeight + (srcWeight >> 7)); +} + +static inline +SkPMColor SkPremultiplyARGBInline(U8CPU a, U8CPU r, U8CPU g, U8CPU b) { + SkA32Assert(a); + SkR32Assert(r); + SkG32Assert(g); + SkB32Assert(b); + + if (a != 255) { + r = SkMulDiv255Round(r, a); + g = SkMulDiv255Round(g, a); + b = SkMulDiv255Round(b, a); + } + return SkPackARGB32(a, r, g, b); +} + +/** + * Interpolates between colors src and dst using [0,256] scale. + */ +static inline SkPMColor SkPMLerp(SkPMColor src, SkPMColor dst, unsigned scale) { + return SkFastFourByteInterp256(src, dst, scale); +} + +static inline SkPMColor SkBlendARGB32(SkPMColor src, SkPMColor dst, U8CPU aa) { + SkASSERT((unsigned)aa <= 255); + + unsigned src_scale = SkAlpha255To256(aa); + unsigned dst_scale = SkAlphaMulInv256(SkGetPackedA32(src), src_scale); + + const uint32_t mask = 0xFF00FF; + + uint32_t src_rb = (src & mask) * src_scale; + uint32_t src_ag = ((src >> 8) & mask) * src_scale; + + uint32_t dst_rb = (dst & mask) * dst_scale; + uint32_t dst_ag = ((dst >> 8) & mask) * dst_scale; + + return (((src_rb + dst_rb) >> 8) & mask) | ((src_ag + dst_ag) & ~mask); +} + +//////////////////////////////////////////////////////////////////////////////////////////// +// Convert a 32bit pixel to a 16bit pixel (no dither) + +#define SkR32ToR16_MACRO(r) ((unsigned)(r) >> (SK_R32_BITS - SK_R16_BITS)) +#define SkG32ToG16_MACRO(g) ((unsigned)(g) >> (SK_G32_BITS - SK_G16_BITS)) +#define SkB32ToB16_MACRO(b) ((unsigned)(b) >> (SK_B32_BITS - SK_B16_BITS)) + +#ifdef SK_DEBUG + static inline unsigned SkR32ToR16(unsigned r) { + SkR32Assert(r); + return SkR32ToR16_MACRO(r); + } + static inline unsigned SkG32ToG16(unsigned g) { + SkG32Assert(g); + return SkG32ToG16_MACRO(g); + } + static inline unsigned SkB32ToB16(unsigned b) { + SkB32Assert(b); + return SkB32ToB16_MACRO(b); + } +#else + #define SkR32ToR16(r) SkR32ToR16_MACRO(r) + #define SkG32ToG16(g) SkG32ToG16_MACRO(g) + #define SkB32ToB16(b) SkB32ToB16_MACRO(b) +#endif + +#define SkPacked32ToR16(c) (((unsigned)(c) >> (SK_R32_SHIFT + SK_R32_BITS - SK_R16_BITS)) & SK_R16_MASK) +#define SkPacked32ToG16(c) (((unsigned)(c) >> (SK_G32_SHIFT + SK_G32_BITS - SK_G16_BITS)) & SK_G16_MASK) +#define SkPacked32ToB16(c) (((unsigned)(c) >> (SK_B32_SHIFT + SK_B32_BITS - SK_B16_BITS)) & SK_B16_MASK) + +static inline U16CPU SkPixel32ToPixel16(SkPMColor c) { + unsigned r = ((c >> (SK_R32_SHIFT + (8 - SK_R16_BITS))) & SK_R16_MASK) << SK_R16_SHIFT; + unsigned g = ((c >> (SK_G32_SHIFT + (8 - SK_G16_BITS))) & SK_G16_MASK) << SK_G16_SHIFT; + unsigned b = ((c >> (SK_B32_SHIFT + (8 - SK_B16_BITS))) & SK_B16_MASK) << SK_B16_SHIFT; + return r | g | b; +} + +static inline U16CPU SkPack888ToRGB16(U8CPU r, U8CPU g, U8CPU b) { + return (SkR32ToR16(r) << SK_R16_SHIFT) | + (SkG32ToG16(g) << SK_G16_SHIFT) | + (SkB32ToB16(b) << SK_B16_SHIFT); +} + +#define SkPixel32ToPixel16_ToU16(src) SkToU16(SkPixel32ToPixel16(src)) + +///////////////////////////////////////////////////////////////////////////////////////// +// Fast dither from 32->16 + +#define SkShouldDitherXY(x, y) (((x) ^ (y)) & 1) + +static inline uint16_t SkDitherPack888ToRGB16(U8CPU r, U8CPU g, U8CPU b) { + r = ((r << 1) - ((r >> (8 - SK_R16_BITS) << (8 - SK_R16_BITS)) | (r >> SK_R16_BITS))) >> (8 - SK_R16_BITS); + g = ((g << 1) - ((g >> (8 - SK_G16_BITS) << (8 - SK_G16_BITS)) | (g >> SK_G16_BITS))) >> (8 - SK_G16_BITS); + b = ((b << 1) - ((b >> (8 - SK_B16_BITS) << (8 - SK_B16_BITS)) | (b >> SK_B16_BITS))) >> (8 - SK_B16_BITS); + + return SkPackRGB16(r, g, b); +} + +static inline uint16_t SkDitherPixel32ToPixel16(SkPMColor c) { + return SkDitherPack888ToRGB16(SkGetPackedR32(c), SkGetPackedG32(c), SkGetPackedB32(c)); +} + +/* Return c in expanded_rgb_16 format, but also scaled up by 32 (5 bits) + It is now suitable for combining with a scaled expanded_rgb_16 color + as in SkSrcOver32To16(). + We must do this 565 high-bit replication, in order for the subsequent add + to saturate properly (and not overflow). If we take the 8 bits as is, it is + possible to overflow. +*/ +static inline uint32_t SkPMColorToExpanded16x5(SkPMColor c) { + unsigned sr = SkPacked32ToR16(c); + unsigned sg = SkPacked32ToG16(c); + unsigned sb = SkPacked32ToB16(c); + + sr = (sr << 5) | sr; + sg = (sg << 5) | (sg >> 1); + sb = (sb << 5) | sb; + return (sr << 11) | (sg << 21) | (sb << 0); +} + +/* SrcOver the 32bit src color with the 16bit dst, returning a 16bit value + (with dirt in the high 16bits, so caller beware). +*/ +static inline U16CPU SkSrcOver32To16(SkPMColor src, uint16_t dst) { + unsigned sr = SkGetPackedR32(src); + unsigned sg = SkGetPackedG32(src); + unsigned sb = SkGetPackedB32(src); + + unsigned dr = SkGetPackedR16(dst); + unsigned dg = SkGetPackedG16(dst); + unsigned db = SkGetPackedB16(dst); + + unsigned isa = 255 - SkGetPackedA32(src); + + dr = (sr + SkMul16ShiftRound(dr, isa, SK_R16_BITS)) >> (8 - SK_R16_BITS); + dg = (sg + SkMul16ShiftRound(dg, isa, SK_G16_BITS)) >> (8 - SK_G16_BITS); + db = (sb + SkMul16ShiftRound(db, isa, SK_B16_BITS)) >> (8 - SK_B16_BITS); + + return SkPackRGB16(dr, dg, db); +} + +//////////////////////////////////////////////////////////////////////////////////////////// +// Convert a 16bit pixel to a 32bit pixel + +static inline unsigned SkR16ToR32(unsigned r) { + return (r << (8 - SK_R16_BITS)) | (r >> (2 * SK_R16_BITS - 8)); +} + +static inline unsigned SkG16ToG32(unsigned g) { + return (g << (8 - SK_G16_BITS)) | (g >> (2 * SK_G16_BITS - 8)); +} + +static inline unsigned SkB16ToB32(unsigned b) { + return (b << (8 - SK_B16_BITS)) | (b >> (2 * SK_B16_BITS - 8)); +} + +#define SkPacked16ToR32(c) SkR16ToR32(SkGetPackedR16(c)) +#define SkPacked16ToG32(c) SkG16ToG32(SkGetPackedG16(c)) +#define SkPacked16ToB32(c) SkB16ToB32(SkGetPackedB16(c)) + +static inline SkPMColor SkPixel16ToPixel32(U16CPU src) { + SkASSERT(src == SkToU16(src)); + + unsigned r = SkPacked16ToR32(src); + unsigned g = SkPacked16ToG32(src); + unsigned b = SkPacked16ToB32(src); + + SkASSERT((r >> (8 - SK_R16_BITS)) == SkGetPackedR16(src)); + SkASSERT((g >> (8 - SK_G16_BITS)) == SkGetPackedG16(src)); + SkASSERT((b >> (8 - SK_B16_BITS)) == SkGetPackedB16(src)); + + return SkPackARGB32(0xFF, r, g, b); +} + +// similar to SkPixel16ToPixel32, but returns SkColor instead of SkPMColor +static inline SkColor SkPixel16ToColor(U16CPU src) { + SkASSERT(src == SkToU16(src)); + + unsigned r = SkPacked16ToR32(src); + unsigned g = SkPacked16ToG32(src); + unsigned b = SkPacked16ToB32(src); + + SkASSERT((r >> (8 - SK_R16_BITS)) == SkGetPackedR16(src)); + SkASSERT((g >> (8 - SK_G16_BITS)) == SkGetPackedG16(src)); + SkASSERT((b >> (8 - SK_B16_BITS)) == SkGetPackedB16(src)); + + return SkColorSetRGB(r, g, b); +} + +/////////////////////////////////////////////////////////////////////////////// + +typedef uint16_t SkPMColor16; + +// Put in OpenGL order (r g b a) +#define SK_A4444_SHIFT 0 +#define SK_R4444_SHIFT 12 +#define SK_G4444_SHIFT 8 +#define SK_B4444_SHIFT 4 + +#define SkA32To4444(a) ((unsigned)(a) >> 4) +#define SkR32To4444(r) ((unsigned)(r) >> 4) +#define SkG32To4444(g) ((unsigned)(g) >> 4) +#define SkB32To4444(b) ((unsigned)(b) >> 4) + +static inline U8CPU SkReplicateNibble(unsigned nib) { + SkASSERT(nib <= 0xF); + return (nib << 4) | nib; +} + +#define SkA4444ToA32(a) SkReplicateNibble(a) +#define SkR4444ToR32(r) SkReplicateNibble(r) +#define SkG4444ToG32(g) SkReplicateNibble(g) +#define SkB4444ToB32(b) SkReplicateNibble(b) + +#define SkGetPackedA4444(c) (((unsigned)(c) >> SK_A4444_SHIFT) & 0xF) +#define SkGetPackedR4444(c) (((unsigned)(c) >> SK_R4444_SHIFT) & 0xF) +#define SkGetPackedG4444(c) (((unsigned)(c) >> SK_G4444_SHIFT) & 0xF) +#define SkGetPackedB4444(c) (((unsigned)(c) >> SK_B4444_SHIFT) & 0xF) + +#define SkPacked4444ToA32(c) SkReplicateNibble(SkGetPackedA4444(c)) +#define SkPacked4444ToR32(c) SkReplicateNibble(SkGetPackedR4444(c)) +#define SkPacked4444ToG32(c) SkReplicateNibble(SkGetPackedG4444(c)) +#define SkPacked4444ToB32(c) SkReplicateNibble(SkGetPackedB4444(c)) + +#ifdef SK_DEBUG +static inline void SkPMColor16Assert(U16CPU c) { + unsigned a = SkGetPackedA4444(c); + unsigned r = SkGetPackedR4444(c); + unsigned g = SkGetPackedG4444(c); + unsigned b = SkGetPackedB4444(c); + + SkASSERT(a <= 0xF); + SkASSERT(r <= a); + SkASSERT(g <= a); + SkASSERT(b <= a); +} +#else +#define SkPMColor16Assert(c) +#endif + +static inline unsigned SkAlpha15To16(unsigned a) { + SkASSERT(a <= 0xF); + return a + (a >> 3); +} + +#ifdef SK_DEBUG + static inline int SkAlphaMul4(int value, int scale) { + SkASSERT((unsigned)scale <= 0x10); + return value * scale >> 4; + } +#else + #define SkAlphaMul4(value, scale) ((value) * (scale) >> 4) +#endif + +static inline unsigned SkR4444ToR565(unsigned r) { + SkASSERT(r <= 0xF); + return (r << (SK_R16_BITS - 4)) | (r >> (8 - SK_R16_BITS)); +} + +static inline unsigned SkG4444ToG565(unsigned g) { + SkASSERT(g <= 0xF); + return (g << (SK_G16_BITS - 4)) | (g >> (8 - SK_G16_BITS)); +} + +static inline unsigned SkB4444ToB565(unsigned b) { + SkASSERT(b <= 0xF); + return (b << (SK_B16_BITS - 4)) | (b >> (8 - SK_B16_BITS)); +} + +static inline SkPMColor16 SkPackARGB4444(unsigned a, unsigned r, + unsigned g, unsigned b) { + SkASSERT(a <= 0xF); + SkASSERT(r <= a); + SkASSERT(g <= a); + SkASSERT(b <= a); + + return (SkPMColor16)((a << SK_A4444_SHIFT) | (r << SK_R4444_SHIFT) | + (g << SK_G4444_SHIFT) | (b << SK_B4444_SHIFT)); +} + +static inline SkPMColor16 SkAlphaMulQ4(SkPMColor16 c, int scale) { + SkASSERT(scale <= 16); + + const unsigned mask = 0xF0F; //gMask_0F0F; + +#if 0 + unsigned rb = ((c & mask) * scale) >> 4; + unsigned ag = ((c >> 4) & mask) * scale; + return (rb & mask) | (ag & ~mask); +#else + unsigned expanded_c = (c & mask) | ((c & (mask << 4)) << 12); + unsigned scaled_c = (expanded_c * scale) >> 4; + return (scaled_c & mask) | ((scaled_c >> 12) & (mask << 4)); +#endif +} + +/** Expand the SkPMColor16 color into a 32bit value that can be scaled all at + once by a value up to 16. +*/ +static inline uint32_t SkExpand_4444(U16CPU c) { + SkASSERT(c == (uint16_t)c); + + const unsigned mask = 0xF0F; //gMask_0F0F; + return (c & mask) | ((c & ~mask) << 12); +} + +static inline uint16_t SkSrcOver4444To16(SkPMColor16 s, uint16_t d) { + unsigned sa = SkGetPackedA4444(s); + unsigned sr = SkR4444ToR565(SkGetPackedR4444(s)); + unsigned sg = SkG4444ToG565(SkGetPackedG4444(s)); + unsigned sb = SkB4444ToB565(SkGetPackedB4444(s)); + + // To avoid overflow, we have to clear the low bit of the synthetic sg + // if the src alpha is <= 7. + // to see why, try blending 0x4444 on top of 565-white and watch green + // overflow (sum == 64) + sg &= ~(~(sa >> 3) & 1); + + unsigned scale = SkAlpha15To16(15 - sa); + unsigned dr = SkAlphaMul4(SkGetPackedR16(d), scale); + unsigned dg = SkAlphaMul4(SkGetPackedG16(d), scale); + unsigned db = SkAlphaMul4(SkGetPackedB16(d), scale); + +#if 0 + if (sg + dg > 63) { + SkDebugf("---- SkSrcOver4444To16 src=%x dst=%x scale=%d, sg=%d dg=%d\n", s, d, scale, sg, dg); + } +#endif + return SkPackRGB16(sr + dr, sg + dg, sb + db); +} + +static inline uint16_t SkBlend4444To16(SkPMColor16 src, uint16_t dst, int scale16) { + SkASSERT((unsigned)scale16 <= 16); + + return SkSrcOver4444To16(SkAlphaMulQ4(src, scale16), dst); +} + +static inline SkPMColor SkPixel4444ToPixel32(U16CPU c) { + uint32_t d = (SkGetPackedA4444(c) << SK_A32_SHIFT) | + (SkGetPackedR4444(c) << SK_R32_SHIFT) | + (SkGetPackedG4444(c) << SK_G32_SHIFT) | + (SkGetPackedB4444(c) << SK_B32_SHIFT); + return d | (d << 4); +} + +static inline SkPMColor16 SkPixel32ToPixel4444(SkPMColor c) { + return (((c >> (SK_A32_SHIFT + 4)) & 0xF) << SK_A4444_SHIFT) | + (((c >> (SK_R32_SHIFT + 4)) & 0xF) << SK_R4444_SHIFT) | + (((c >> (SK_G32_SHIFT + 4)) & 0xF) << SK_G4444_SHIFT) | + (((c >> (SK_B32_SHIFT + 4)) & 0xF) << SK_B4444_SHIFT); +} + +// cheap 2x2 dither +static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, + U8CPU g, U8CPU b) { + // to ensure that we stay a legal premultiplied color, we take the max() + // of the truncated and dithered alpha values. If we didn't, cases like + // SkDitherARGB32To4444(0x31, 0x2E, ...) would generate SkPackARGB4444(2, 3, ...) + // which is not legal premultiplied, since a < color + unsigned dithered_a = ((a << 1) - ((a >> 4 << 4) | (a >> 4))) >> 4; + a = SkMax32(a >> 4, dithered_a); + // these we just dither in place + r = ((r << 1) - ((r >> 4 << 4) | (r >> 4))) >> 4; + g = ((g << 1) - ((g >> 4 << 4) | (g >> 4))) >> 4; + b = ((b << 1) - ((b >> 4 << 4) | (b >> 4))) >> 4; + + return SkPackARGB4444(a, r, g, b); +} + +static inline SkPMColor16 SkDitherPixel32To4444(SkPMColor c) { + return SkDitherARGB32To4444(SkGetPackedA32(c), SkGetPackedR32(c), + SkGetPackedG32(c), SkGetPackedB32(c)); +} + +/* Assumes 16bit is in standard RGBA order. + Transforms a normal ARGB_8888 into the same byte order as + expanded ARGB_4444, but keeps each component 8bits +*/ +static inline uint32_t SkExpand_8888(SkPMColor c) { + return (((c >> SK_R32_SHIFT) & 0xFF) << 24) | + (((c >> SK_G32_SHIFT) & 0xFF) << 8) | + (((c >> SK_B32_SHIFT) & 0xFF) << 16) | + (((c >> SK_A32_SHIFT) & 0xFF) << 0); +} + +/* Undo the operation of SkExpand_8888, turning the argument back into + a SkPMColor. +*/ +static inline SkPMColor SkCompact_8888(uint32_t c) { + return (((c >> 24) & 0xFF) << SK_R32_SHIFT) | + (((c >> 8) & 0xFF) << SK_G32_SHIFT) | + (((c >> 16) & 0xFF) << SK_B32_SHIFT) | + (((c >> 0) & 0xFF) << SK_A32_SHIFT); +} + +/* Like SkExpand_8888, this transforms a pmcolor into the expanded 4444 format, + but this routine just keeps the high 4bits of each component in the low + 4bits of the result (just like a newly expanded PMColor16). +*/ +static inline uint32_t SkExpand32_4444(SkPMColor c) { + return (((c >> (SK_R32_SHIFT + 4)) & 0xF) << 24) | + (((c >> (SK_G32_SHIFT + 4)) & 0xF) << 8) | + (((c >> (SK_B32_SHIFT + 4)) & 0xF) << 16) | + (((c >> (SK_A32_SHIFT + 4)) & 0xF) << 0); +} + +// takes two values and alternamtes them as part of a memset16 +// used for cheap 2x2 dithering when the colors are opaque +void sk_dither_memset16(uint16_t dst[], uint16_t value, uint16_t other, int n); + +/////////////////////////////////////////////////////////////////////////////// + +static inline int SkUpscale31To32(int value) { + SkASSERT((unsigned)value <= 31); + return value + (value >> 4); +} + +static inline int SkBlend32(int src, int dst, int scale) { + SkASSERT((unsigned)src <= 0xFF); + SkASSERT((unsigned)dst <= 0xFF); + SkASSERT((unsigned)scale <= 32); + return dst + ((src - dst) * scale >> 5); +} + +static inline SkPMColor SkBlendLCD16(int srcA, int srcR, int srcG, int srcB, + SkPMColor dst, uint16_t mask) { + if (mask == 0) { + return dst; + } + + /* We want all of these in 5bits, hence the shifts in case one of them + * (green) is 6bits. + */ + int maskR = SkGetPackedR16(mask) >> (SK_R16_BITS - 5); + int maskG = SkGetPackedG16(mask) >> (SK_G16_BITS - 5); + int maskB = SkGetPackedB16(mask) >> (SK_B16_BITS - 5); + + // Now upscale them to 0..32, so we can use blend32 + maskR = SkUpscale31To32(maskR); + maskG = SkUpscale31To32(maskG); + maskB = SkUpscale31To32(maskB); + + // srcA has been upscaled to 256 before passed into this function + maskR = maskR * srcA >> 8; + maskG = maskG * srcA >> 8; + maskB = maskB * srcA >> 8; + + int dstR = SkGetPackedR32(dst); + int dstG = SkGetPackedG32(dst); + int dstB = SkGetPackedB32(dst); + + // LCD blitting is only supported if the dst is known/required + // to be opaque + return SkPackARGB32(0xFF, + SkBlend32(srcR, dstR, maskR), + SkBlend32(srcG, dstG, maskG), + SkBlend32(srcB, dstB, maskB)); +} + +static inline SkPMColor SkBlendLCD16Opaque(int srcR, int srcG, int srcB, + SkPMColor dst, uint16_t mask, + SkPMColor opaqueDst) { + if (mask == 0) { + return dst; + } + + if (0xFFFF == mask) { + return opaqueDst; + } + + /* We want all of these in 5bits, hence the shifts in case one of them + * (green) is 6bits. + */ + int maskR = SkGetPackedR16(mask) >> (SK_R16_BITS - 5); + int maskG = SkGetPackedG16(mask) >> (SK_G16_BITS - 5); + int maskB = SkGetPackedB16(mask) >> (SK_B16_BITS - 5); + + // Now upscale them to 0..32, so we can use blend32 + maskR = SkUpscale31To32(maskR); + maskG = SkUpscale31To32(maskG); + maskB = SkUpscale31To32(maskB); + + int dstR = SkGetPackedR32(dst); + int dstG = SkGetPackedG32(dst); + int dstB = SkGetPackedB32(dst); + + // LCD blitting is only supported if the dst is known/required + // to be opaque + return SkPackARGB32(0xFF, + SkBlend32(srcR, dstR, maskR), + SkBlend32(srcG, dstG, maskG), + SkBlend32(srcB, dstB, maskB)); +} + +static inline void SkBlitLCD16Row(SkPMColor dst[], const uint16_t mask[], + SkColor src, int width, SkPMColor) { + int srcA = SkColorGetA(src); + int srcR = SkColorGetR(src); + int srcG = SkColorGetG(src); + int srcB = SkColorGetB(src); + + srcA = SkAlpha255To256(srcA); + + for (int i = 0; i < width; i++) { + dst[i] = SkBlendLCD16(srcA, srcR, srcG, srcB, dst[i], mask[i]); + } +} + +static inline void SkBlitLCD16OpaqueRow(SkPMColor dst[], const uint16_t mask[], + SkColor src, int width, + SkPMColor opaqueDst) { + int srcR = SkColorGetR(src); + int srcG = SkColorGetG(src); + int srcB = SkColorGetB(src); + + for (int i = 0; i < width; i++) { + dst[i] = SkBlendLCD16Opaque(srcR, srcG, srcB, dst[i], mask[i], + opaqueDst); + } +} + +#endif |