// returns answer in SkPMColor format
static inline SkPMColor Filter_4444_D32(unsigned x, unsigned y,
uint32_t a00, uint32_t a01,
uint32_t a10, uint32_t a11) {
SkASSERT((unsigned)x <= 0xF);
SkASSERT((unsigned)y <= 0xF);
a00 = SkExpand_4444(a00);
a01 = SkExpand_4444(a01);
a10 = SkExpand_4444(a10);
a11 = SkExpand_4444(a11);
int xy = x * y >> 4;
uint32_t result = a00 * (16 - y - x + xy) +
a01 * (x - xy) +
a10 * (y - xy) +
a11 * xy;
return SkCompact_8888(result);
}
void SkTransparentShader::shadeSpan(int x, int y, SkPMColor span[], int count) {
unsigned scale = SkAlpha255To256(fAlpha);
switch (fDevice->getConfig()) {
case SkBitmap::kARGB_8888_Config:
if (scale == 256) {
SkPMColor* src = fDevice->getAddr32(x, y);
if (src != span) {
memcpy(span, src, count * sizeof(SkPMColor));
}
} else {
const SkPMColor* src = fDevice->getAddr32(x, y);
for (int i = count - 1; i >= 0; --i) {
span[i] = SkAlphaMulQ(src[i], scale);
}
}
break;
case SkBitmap::kRGB_565_Config: {
const uint16_t* src = fDevice->getAddr16(x, y);
if (scale == 256) {
for (int i = count - 1; i >= 0; --i) {
span[i] = SkPixel16ToPixel32(src[i]);
}
} else {
unsigned alpha = fAlpha;
for (int i = count - 1; i >= 0; --i) {
uint16_t c = src[i];
unsigned r = SkPacked16ToR32(c);
unsigned g = SkPacked16ToG32(c);
unsigned b = SkPacked16ToB32(c);
span[i] = SkPackARGB32( alpha,
SkAlphaMul(r, scale),
SkAlphaMul(g, scale),
SkAlphaMul(b, scale));
}
}
break;
}
case SkBitmap::kARGB_4444_Config: {
const uint16_t* src = fDevice->getAddr16(x, y);
if (scale == 256) {
for (int i = count - 1; i >= 0; --i) {
span[i] = SkPixel4444ToPixel32(src[i]);
}
} else {
unsigned scale16 = scale >> 4;
for (int i = count - 1; i >= 0; --i) {
uint32_t c = SkExpand_4444(src[i]) * scale16;
span[i] = SkCompact_8888(c);
}
}
break;
}
case SkBitmap::kIndex8_Config:
SkDEBUGFAIL("index8 not supported as a destination device");
break;
case SkBitmap::kA8_Config: {
const uint8_t* src = fDevice->getAddr8(x, y);
if (scale == 256) {
for (int i = count - 1; i >= 0; --i) {
span[i] = SkPackARGB32(src[i], 0, 0, 0);
}
} else {
for (int i = count - 1; i >= 0; --i) {
span[i] = SkPackARGB32(SkAlphaMul(src[i], scale), 0, 0, 0);
}
}
break;
}
case SkBitmap::kA1_Config:
SkDEBUGFAIL("kA1_Config umimplemented at this time");
break;
default: // to avoid warnings
break;
}
}
