Proposal for SkImageGenerator::canDecodeAndScale API

src/core/SkImageGenerator.cpp

Index: src/core/SkImageGenerator.cpp
diff --git a/src/core/SkImageGenerator.cpp b/src/core/SkImageGenerator.cpp
index 440ae7f5b8f202f1175dc9ad2faef5e9826ccbd5..b6cb630d7c7d5a9ccd036dccc741b3666f63c1d2 100644
--- a/src/core/SkImageGenerator.cpp
+++ b/src/core/SkImageGenerator.cpp
@@ -198,6 +198,28 @@ bool SkImageGenerator::tryGenerateBitmap(SkBitmap* bitmap, const SkImageInfo* in
     return true;
 }
 
+SkImageGenerator::Result SkImageGenerator::canDecodeAndScale(const SkColorType colorType, const SkScalar scale, SkISize* availableSize, SkISize* lowerSize) {
+    return this->onCanDecodeAndScale(colorType, scale, availableSize, lowerSize);
+}
+
+SkImageGenerator::Result SkImageGenerator::onCanDecodeAndScale(const SkColorType colorType, const SkScalar scale, SkISize* availableSize, SkISize* lowerSize) {
+    unsigned result = SkImageGenerator::kNotAvailable;
+    if (colorType == fInfo.colorType())
+        result |= SkImageGenerator::kDecode;
+    if (scale == SK_Scalar1) {
+        result |= SkImageGenerator::kScale;
+        if (availableSize) {
+            availableSize->fWidth = fInfo.width();
+            availableSize->fHeight = fInfo.height();
+        }
+        if (lowerSize) {
+            availableSize->fWidth = availableSize->fHeight = 0;
+        }
+    }
+    return static_cast<SkImageGenerator::Result>(result);
+}
+
+
 #include "SkGraphics.h"
 
 static SkGraphics::ImageGeneratorFromEncodedFactory gFactory;