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/* libs/graphics/effects/SkTransparentShader.cpp
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include "SkTransparentShader.h"
#include "SkColorPriv.h"
bool SkTransparentShader::setContext(const SkBitmap& device,
const SkPaint& paint,
const SkMatrix& matrix)
{
fDevice = &device;
fAlpha = paint.getAlpha();
return this->INHERITED::setContext(device, paint, matrix);
}
uint32_t SkTransparentShader::getFlags()
{
uint32_t flags = this->INHERITED::getFlags();
switch (fDevice->getConfig()) {
case SkBitmap::kRGB_565_Config:
flags |= kHasSpan16_Flag;
if (fAlpha == 255)
flags |= kOpaqueAlpha_Flag;
break;
case SkBitmap::kARGB_8888_Config:
case SkBitmap::kARGB_4444_Config:
if (fAlpha == 255 && fDevice->isOpaque())
flags |= kOpaqueAlpha_Flag;
break;
default:
break;
}
return flags;
}
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)
memcpy(span, fDevice->getAddr32(x, y), 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:
SkASSERT(!"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:
SkASSERT(!"kA1_Config umimplemented at this time");
break;
default: // to avoid warnings
break;
}
}
void SkTransparentShader::shadeSpan16(int x, int y, uint16_t span[], int count)
{
SkASSERT(fDevice->getConfig() == SkBitmap::kRGB_565_Config);
memcpy(span, fDevice->getAddr16(x, y), count << 1);
}
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