SkARGB4444_Blitter::SkARGB4444_Blitter(const SkBitmap& device, const SkPaint& paint) : INHERITED(device) { // cache premultiplied versions in 4444 SkPMColor c = SkPreMultiplyColor(paint.getColor()); fPMColor16 = SkPixel32ToPixel4444(c); if (paint.isDither()) { fPMColor16Other = SkDitherPixel32To4444(c); } else { fPMColor16Other = fPMColor16; } // cache raw versions in 4444 fRawColor16 = SkPackARGB4444(0xFF >> 4, SkColorGetR(c) >> 4, SkColorGetG(c) >> 4, SkColorGetB(c) >> 4); if (paint.isDither()) { fRawColor16Other = SkDitherARGB32To4444(0xFF, SkColorGetR(c), SkColorGetG(c), SkColorGetB(c)); } else { fRawColor16Other = fRawColor16; } fScale16 = SkAlpha15To16(SkGetPackedA4444(fPMColor16Other)); if (16 == fScale16) { // force the original to also be opaque fPMColor16 |= (0xF << SK_A4444_SHIFT); } }
SkARGB4444_Blitter::SkARGB4444_Blitter(const SkBitmap& device, const SkPaint& paint) : INHERITED(device) { // cache premultiplied versions in 4444 SkPMColor c = SkPreMultiplyColor(paint.getColor()); fPMColor16 = SkPixel32ToPixel4444(c); if (paint.isDither()) { fPMColor16Other = SkDitherPixel32To4444(c); } else { fPMColor16Other = fPMColor16; } // cache raw versions in 4444 fRawColor16 = SkPackARGB4444(0xFF >> 4, SkColorGetR(c) >> 4, SkColorGetG(c) >> 4, SkColorGetB(c) >> 4); if (paint.isDither()) { fRawColor16Other = SkDitherARGB32To4444(0xFF, SkColorGetR(c), SkColorGetG(c), SkColorGetB(c)); } else { fRawColor16Other = fRawColor16; } #if 0 /// don't think this assertion is true, but need it be? // our dithered color will be the same or more opaque than the original // so use dithered to compute our scale SkASSERT(SkGetPackedA4444(fPMColor16Other) >= SkGetPackedA4444(fPMColor16)); #endif fScale16 = SkAlpha15To16(SkGetPackedA4444(fPMColor16Other)); if (16 == fScale16) { // force the original to also be opaque fPMColor16 |= (0xF << SK_A4444_SHIFT); } }
static inline SkPMColor SkBlendARGB4444(SkPMColor16 src, SkPMColor16 dst, U8CPU aa) { SkASSERT((unsigned)aa <= 255); unsigned src_scale = SkAlpha255To256(aa) >> 4; unsigned dst_scale = SkAlpha15To16(15 - SkAlphaMul4(SkGetPackedA4444(src), src_scale)); uint32_t src32 = SkExpand_4444(src) * src_scale; uint32_t dst32 = SkExpand_4444(dst) * dst_scale; return SkCompact_4444((src32 + dst32) >> 4); }