Adding isOpaque method to skia shader classes
REVIEW=http://codereview.appspot.com/5451102/
TEST=unit test ShaderOpacity
git-svn-id: http://skia.googlecode.com/svn/trunk@2840 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkGradientShader.cpp b/src/effects/SkGradientShader.cpp
index bc7f8a3..af357a6 100644
--- a/src/effects/SkGradientShader.cpp
+++ b/src/effects/SkGradientShader.cpp
@@ -119,6 +119,7 @@
// overrides
virtual bool setContext(const SkBitmap&, const SkPaint&, const SkMatrix&) SK_OVERRIDE;
virtual uint32_t getFlags() SK_OVERRIDE { return fFlags; }
+ virtual bool isOpaque() const SK_OVERRIDE;
protected:
Gradient_Shader(SkFlattenableReadBuffer& );
@@ -161,7 +162,8 @@
kStorageSize = kColorStorageCount * (sizeof(SkColor) + sizeof(Rec))
};
SkColor fStorage[(kStorageSize + 3) >> 2];
- SkColor* fOrigColors;
+ SkColor* fOrigColors; // original colors, before modulation by paint in setContext
+ bool fColorsAreOpaque;
mutable uint16_t* fCache16; // working ptr. If this is NULL, we need to recompute the cache values
mutable SkPMColor* fCache32; // working ptr. If this is NULL, we need to recompute the cache values
@@ -174,6 +176,7 @@
static void Build32bitCache(SkPMColor[], SkColor c0, SkColor c1, int count,
U8CPU alpha);
void setCacheAlpha(U8CPU alpha) const;
+ void initCommon();
typedef SkShader INHERITED;
};
@@ -302,7 +305,7 @@
}
}
}
- fFlags = 0;
+ this->initCommon();
}
Gradient_Shader::Gradient_Shader(SkFlattenableReadBuffer& buffer) :
@@ -336,7 +339,7 @@
}
}
SkReadMatrix(&buffer, &fPtsToUnit);
- fFlags = 0;
+ this->initCommon();
}
Gradient_Shader::~Gradient_Shader() {
@@ -350,6 +353,15 @@
SkSafeUnref(fMapper);
}
+void Gradient_Shader::initCommon() {
+ fFlags = 0;
+ unsigned colorAlpha = 0xFF;
+ for (int i = 0; i < fColorCount; i++) {
+ colorAlpha &= SkColorGetA(fOrigColors[i]);
+ }
+ fColorsAreOpaque = colorAlpha == 0xFF;
+}
+
void Gradient_Shader::flatten(SkFlattenableWriteBuffer& buffer) {
this->INHERITED::flatten(buffer);
buffer.writeFlattenable(fMapper);
@@ -366,6 +378,10 @@
SkWriteMatrix(&buffer, fPtsToUnit);
}
+bool Gradient_Shader::isOpaque() const {
+ return fColorsAreOpaque;
+}
+
bool Gradient_Shader::setContext(const SkBitmap& device,
const SkPaint& paint,
const SkMatrix& matrix) {
@@ -384,23 +400,14 @@
// now convert our colors in to PMColors
unsigned paintAlpha = this->getPaintAlpha();
- unsigned colorAlpha = 0xFF;
-
- // FIXME: record colorAlpha in constructor, since this is not affected
- // by setContext()
- for (int i = 0; i < fColorCount; i++) {
- SkColor src = fOrigColors[i];
- unsigned sa = SkColorGetA(src);
- colorAlpha &= sa;
- }
fFlags = this->INHERITED::getFlags();
- if ((colorAlpha & paintAlpha) == 0xFF) {
+ if (fColorsAreOpaque && paintAlpha == 0xFF) {
fFlags |= kOpaqueAlpha_Flag;
}
// we can do span16 as long as our individual colors are opaque,
// regardless of the paint's alpha
- if (0xFF == colorAlpha) {
+ if (fColorsAreOpaque) {
fFlags |= kHasSpan16_Flag;
}