michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #include "SkTransparentShader.h"
michael@0: #include "SkColorPriv.h"
michael@0: #include "SkString.h"
michael@0: 
michael@0: bool SkTransparentShader::setContext(const SkBitmap& device,
michael@0:                                      const SkPaint& paint,
michael@0:                                      const SkMatrix& matrix) {
michael@0:     fDevice = &device;
michael@0:     fAlpha = paint.getAlpha();
michael@0: 
michael@0:     return this->INHERITED::setContext(device, paint, matrix);
michael@0: }
michael@0: 
michael@0: uint32_t SkTransparentShader::getFlags() {
michael@0:     uint32_t flags = this->INHERITED::getFlags();
michael@0: 
michael@0:     switch (fDevice->colorType()) {
michael@0:         case kRGB_565_SkColorType:
michael@0:             flags |= kHasSpan16_Flag;
michael@0:             if (fAlpha == 255)
michael@0:                 flags |= kOpaqueAlpha_Flag;
michael@0:             break;
michael@0:         case kPMColor_SkColorType:
michael@0:             if (fAlpha == 255 && fDevice->isOpaque())
michael@0:                 flags |= kOpaqueAlpha_Flag;
michael@0:             break;
michael@0:         default:
michael@0:             break;
michael@0:     }
michael@0:     return flags;
michael@0: }
michael@0: 
michael@0: void SkTransparentShader::shadeSpan(int x, int y, SkPMColor span[], int count) {
michael@0:     unsigned scale = SkAlpha255To256(fAlpha);
michael@0: 
michael@0:     switch (fDevice->colorType()) {
michael@0:         case kPMColor_SkColorType:
michael@0:             if (scale == 256) {
michael@0:                 SkPMColor* src = fDevice->getAddr32(x, y);
michael@0:                 if (src != span) {
michael@0:                     memcpy(span, src, count * sizeof(SkPMColor));
michael@0:                 }
michael@0:             } else {
michael@0:                 const SkPMColor* src = fDevice->getAddr32(x, y);
michael@0:                 for (int i = count - 1; i >= 0; --i) {
michael@0:                     span[i] = SkAlphaMulQ(src[i], scale);
michael@0:                 }
michael@0:             }
michael@0:             break;
michael@0:         case kRGB_565_SkColorType: {
michael@0:             const uint16_t* src = fDevice->getAddr16(x, y);
michael@0:             if (scale == 256) {
michael@0:                 for (int i = count - 1; i >= 0; --i) {
michael@0:                     span[i] = SkPixel16ToPixel32(src[i]);
michael@0:                 }
michael@0:             } else {
michael@0:                 unsigned alpha = fAlpha;
michael@0:                 for (int i = count - 1; i >= 0; --i) {
michael@0:                     uint16_t c = src[i];
michael@0:                     unsigned r = SkPacked16ToR32(c);
michael@0:                     unsigned g = SkPacked16ToG32(c);
michael@0:                     unsigned b = SkPacked16ToB32(c);
michael@0: 
michael@0:                     span[i] = SkPackARGB32( alpha,
michael@0:                                             SkAlphaMul(r, scale),
michael@0:                                             SkAlphaMul(g, scale),
michael@0:                                             SkAlphaMul(b, scale));
michael@0:                 }
michael@0:             }
michael@0:             break;
michael@0:         }
michael@0:         case kAlpha_8_SkColorType: {
michael@0:             const uint8_t* src = fDevice->getAddr8(x, y);
michael@0:             if (scale == 256) {
michael@0:                 for (int i = count - 1; i >= 0; --i) {
michael@0:                     span[i] = SkPackARGB32(src[i], 0, 0, 0);
michael@0:                 }
michael@0:             } else {
michael@0:                 for (int i = count - 1; i >= 0; --i) {
michael@0:                     span[i] = SkPackARGB32(SkAlphaMul(src[i], scale), 0, 0, 0);
michael@0:                 }
michael@0:             }
michael@0:             break;
michael@0:         }
michael@0:         default:
michael@0:             SkDEBUGFAIL("colorType not supported as a destination device");
michael@0:             break;
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkTransparentShader::shadeSpan16(int x, int y, uint16_t span[], int count) {
michael@0:     SkASSERT(fDevice->colorType() == kRGB_565_SkColorType);
michael@0: 
michael@0:     uint16_t* src = fDevice->getAddr16(x, y);
michael@0:     if (src != span) {
michael@0:         memcpy(span, src, count << 1);
michael@0:     }
michael@0: }
michael@0: 
michael@0: #ifndef SK_IGNORE_TO_STRING
michael@0: void SkTransparentShader::toString(SkString* str) const {
michael@0:     str->append("SkTransparentShader: (");
michael@0: 
michael@0:     this->INHERITED::toString(str);
michael@0: 
michael@0:     str->append(")");
michael@0: }
michael@0: #endif