Implement crop rect for SkImageFilter

src/core/SkImageFilter.cpp

Index: src/core/SkImageFilter.cpp
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index ddd6449490ba0c0734cfaa925a610f24f704485b..94fe834cffc50b7fb7eece0617f06878fcd925fd 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -18,22 +18,22 @@
 
 SK_DEFINE_INST_COUNT(SkImageFilter)
 
-SkImageFilter::SkImageFilter(int inputCount, SkImageFilter** inputs)
-  : fInputCount(inputCount), fInputs(new SkImageFilter*[inputCount]) {
+SkImageFilter::SkImageFilter(int inputCount, SkImageFilter** inputs, const SkIRect* cropRect)

[reed1, 2013/07/19 21:34:04]

line-wrap

+  : fInputCount(inputCount), fInputs(new SkImageFilter*[inputCount]), fCropRect(cropRect ? *cropRect : SkIRect::MakeLargest()) {
     for (int i = 0; i < inputCount; ++i) {
         fInputs[i] = inputs[i];
         SkSafeRef(fInputs[i]);
     }
 }
 
-SkImageFilter::SkImageFilter(SkImageFilter* input)
-  : fInputCount(1), fInputs(new SkImageFilter*[1]) {
+SkImageFilter::SkImageFilter(SkImageFilter* input, const SkIRect* cropRect)
+  : fInputCount(1), fInputs(new SkImageFilter*[1]), fCropRect(cropRect ? *cropRect : SkIRect::MakeLargest()) {
     fInputs[0] = input;
     SkSafeRef(fInputs[0]);
 }
 
-SkImageFilter::SkImageFilter(SkImageFilter* input1, SkImageFilter* input2)
-  : fInputCount(2), fInputs(new SkImageFilter*[2]) {
+SkImageFilter::SkImageFilter(SkImageFilter* input1, SkImageFilter* input2, const SkIRect* cropRect)
+  : fInputCount(2), fInputs(new SkImageFilter*[2]), fCropRect(cropRect ? *cropRect : SkIRect::MakeLargest()) {
     fInputs[0] = input1;
     fInputs[1] = input2;
     SkSafeRef(fInputs[0]);
@@ -56,6 +56,7 @@ SkImageFilter::SkImageFilter(SkFlattenableReadBuffer& buffer)
             fInputs[i] = NULL;
         }
     }
+    buffer.readIRect(&fCropRect);
 }
 
 void SkImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
@@ -67,6 +68,7 @@ void SkImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
             buffer.writeFlattenable(input);
         }
     }
+    buffer.writeIRect(fCropRect);
 }
 
 bool SkImageFilter::filterImage(Proxy* proxy, const SkBitmap& src,
@@ -137,6 +139,10 @@ bool SkImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, SkBitmap*
 #endif
 }
 
+void SkImageFilter::applyCropRect(SkIRect* rect) const {

[reed1, 2013/07/19 21:34:04]

How is this documented to behave if rect and fCropRect do not intersect? Should
this method return a bool, as the rect-method does?

[Stephen White, 2013/07/19 22:11:50]

That's a good point!

The SVG spec doesn't call out empty intersections explicitly, but just says "All
intermediate offscreens are defined to not exceed the intersection of ‘x’, ‘y’,
‘width’ and ‘height’ with the filter region." So it seems we have to return a
0x0 bitmap, at least semantically.

It looks like the GPU backend doesn't like 0x0 textures, so I think we should
leave the result bitmap untouched and early-out (maybe even before processing
inputs). Does that make sense?

+    rect->intersect(fCropRect);
+}
+
 bool SkImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
                                    SkIRect* dst) {
     *dst = src;