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/*
* 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.
*/
#include "SkComposeShader.h"
#include "SkColorFilter.h"
#include "SkColorPriv.h"
#include "SkColorShader.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
#include "SkXfermode.h"
#include "SkString.h"
///////////////////////////////////////////////////////////////////////////////
SkComposeShader::SkComposeShader(SkShader* sA, SkShader* sB, SkXfermode* mode) {
fShaderA = sA; sA->ref();
fShaderB = sB; sB->ref();
// mode may be null
fMode = mode;
SkSafeRef(mode);
}
SkComposeShader::~SkComposeShader() {
SkSafeUnref(fMode);
fShaderB->unref();
fShaderA->unref();
}
size_t SkComposeShader::contextSize() const {
return sizeof(ComposeShaderContext) + fShaderA->contextSize() + fShaderB->contextSize();
}
class SkAutoAlphaRestore {
public:
SkAutoAlphaRestore(SkPaint* paint, uint8_t newAlpha) {
fAlpha = paint->getAlpha();
fPaint = paint;
paint->setAlpha(newAlpha);
}
~SkAutoAlphaRestore() {
fPaint->setAlpha(fAlpha);
}
private:
SkPaint* fPaint;
uint8_t fAlpha;
};
#define SkAutoAlphaRestore(...) SK_REQUIRE_LOCAL_VAR(SkAutoAlphaRestore)
SkFlattenable* SkComposeShader::CreateProc(SkReadBuffer& buffer) {
SkAutoTUnref<SkShader> shaderA(buffer.readShader());
SkAutoTUnref<SkShader> shaderB(buffer.readShader());
SkAutoTUnref<SkXfermode> mode(buffer.readXfermode());
if (!shaderA.get() || !shaderB.get()) {
return NULL;
}
return SkNEW_ARGS(SkComposeShader, (shaderA, shaderB, mode));
}
void SkComposeShader::flatten(SkWriteBuffer& buffer) const {
buffer.writeFlattenable(fShaderA);
buffer.writeFlattenable(fShaderB);
buffer.writeFlattenable(fMode);
}
template <typename T> void safe_call_destructor(T* obj) {
if (obj) {
obj->~T();
}
}
SkShader::Context* SkComposeShader::onCreateContext(const ContextRec& rec, void* storage) const {
char* aStorage = (char*) storage + sizeof(ComposeShaderContext);
char* bStorage = aStorage + fShaderA->contextSize();
// we preconcat our localMatrix (if any) with the device matrix
// before calling our sub-shaders
SkMatrix tmpM;
tmpM.setConcat(*rec.fMatrix, this->getLocalMatrix());
// Our sub-shaders need to see opaque, so by combining them we don't double-alphatize the
// result. ComposeShader itself will respect the alpha, and post-apply it after calling the
// sub-shaders.
SkPaint opaquePaint(*rec.fPaint);
opaquePaint.setAlpha(0xFF);
ContextRec newRec(rec);
newRec.fMatrix = &tmpM;
newRec.fPaint = &opaquePaint;
SkShader::Context* contextA = fShaderA->createContext(newRec, aStorage);
SkShader::Context* contextB = fShaderB->createContext(newRec, bStorage);
if (!contextA || !contextB) {
safe_call_destructor(contextA);
safe_call_destructor(contextB);
return NULL;
}
return SkNEW_PLACEMENT_ARGS(storage, ComposeShaderContext, (*this, rec, contextA, contextB));
}
SkComposeShader::ComposeShaderContext::ComposeShaderContext(
const SkComposeShader& shader, const ContextRec& rec,
SkShader::Context* contextA, SkShader::Context* contextB)
: INHERITED(shader, rec)
, fShaderContextA(contextA)
, fShaderContextB(contextB) {}
SkComposeShader::ComposeShaderContext::~ComposeShaderContext() {
fShaderContextA->~Context();
fShaderContextB->~Context();
}
bool SkComposeShader::asACompose(ComposeRec* rec) const {
if (rec) {
rec->fShaderA = fShaderA;
rec->fShaderB = fShaderB;
rec->fMode = fMode;
}
return true;
}
// larger is better (fewer times we have to loop), but we shouldn't
// take up too much stack-space (each element is 4 bytes)
#define TMP_COLOR_COUNT 64
void SkComposeShader::ComposeShaderContext::shadeSpan(int x, int y, SkPMColor result[], int count) {
SkShader::Context* shaderContextA = fShaderContextA;
SkShader::Context* shaderContextB = fShaderContextB;
SkXfermode* mode = static_cast<const SkComposeShader&>(fShader).fMode;
unsigned scale = SkAlpha255To256(this->getPaintAlpha());
#ifdef SK_BUILD_FOR_ANDROID
scale = 256; // ugh -- maintain old bug/behavior for now
#endif
SkPMColor tmp[TMP_COLOR_COUNT];
if (NULL == mode) { // implied SRC_OVER
// TODO: when we have a good test-case, should use SkBlitRow::Proc32
// for these loops
do {
int n = count;
if (n > TMP_COLOR_COUNT) {
n = TMP_COLOR_COUNT;
}
shaderContextA->shadeSpan(x, y, result, n);
shaderContextB->shadeSpan(x, y, tmp, n);
if (256 == scale) {
for (int i = 0; i < n; i++) {
result[i] = SkPMSrcOver(tmp[i], result[i]);
}
} else {
for (int i = 0; i < n; i++) {
result[i] = SkAlphaMulQ(SkPMSrcOver(tmp[i], result[i]),
scale);
}
}
result += n;
x += n;
count -= n;
} while (count > 0);
} else { // use mode for the composition
do {
int n = count;
if (n > TMP_COLOR_COUNT) {
n = TMP_COLOR_COUNT;
}
shaderContextA->shadeSpan(x, y, result, n);
shaderContextB->shadeSpan(x, y, tmp, n);
mode->xfer32(result, tmp, n, NULL);
if (256 != scale) {
for (int i = 0; i < n; i++) {
result[i] = SkAlphaMulQ(result[i], scale);
}
}
result += n;
x += n;
count -= n;
} while (count > 0);
}
}
#ifndef SK_IGNORE_TO_STRING
void SkComposeShader::toString(SkString* str) const {
str->append("SkComposeShader: (");
str->append("ShaderA: ");
fShaderA->toString(str);
str->append(" ShaderB: ");
fShaderB->toString(str);
str->append(" Xfermode: ");
fMode->toString(str);
this->INHERITED::toString(str);
str->append(")");
}
#endif
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