Make BitmapRegionDecoder succeed on invalid requests

src/android/SkBitmapRegionCodec.cpp

Index: src/android/SkBitmapRegionCodec.cpp
diff --git a/src/android/SkBitmapRegionCodec.cpp b/src/android/SkBitmapRegionCodec.cpp
index 415b60c5ab354e9ddeac605585e02b4e68244c30..2569ac598bacf5d538060ae20d00df65deaabc84 100644
--- a/src/android/SkBitmapRegionCodec.cpp
+++ b/src/android/SkBitmapRegionCodec.cpp
@@ -17,7 +17,7 @@ SkBitmapRegionCodec::SkBitmapRegionCodec(SkAndroidCodec* codec)
 {}
 
 bool SkBitmapRegionCodec::decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocator,
-        const SkIRect& desiredSubset, int sampleSize, SkColorType dstColorType,
+        const SkIRect& desiredSubset, int sampleSize, SkColorType prefColorType,
         bool requireUnpremul) {
 
     // Fix the input sampleSize if necessary.
@@ -50,10 +50,10 @@ bool SkBitmapRegionCodec::decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocat
     SkISize scaledSize = fCodec->getSampledSubsetDimensions(sampleSize, subset);
 
     // Create the image info for the decode
-    SkAlphaType dstAlphaType = fCodec->getInfo().alphaType();
-    if (kOpaque_SkAlphaType != dstAlphaType) {
-        dstAlphaType = requireUnpremul ? kUnpremul_SkAlphaType : kPremul_SkAlphaType;
-    }
+    SkColorType dstColorType = SkAndroidCodec::FixRequestedColorType(prefColorType,
+            fCodec->getInfo().colorType(), fCodec->getInfo().alphaType());
+    SkAlphaType dstAlphaType = SkAndroidCodec::FixRequestedAlphaType(requireUnpremul,
+            fCodec->getInfo().alphaType());
     SkImageInfo decodeInfo = SkImageInfo::Make(scaledSize.width(), scaledSize.height(),
             dstColorType, dstAlphaType);
 
@@ -94,6 +94,9 @@ bool SkBitmapRegionCodec::decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocat
         scaledOutHeight += scaledOutY + scaledExtraY;
     }
     SkImageInfo outInfo = decodeInfo.makeWH(scaledOutWidth, scaledOutHeight);
+    if (kGray_8_SkColorType == dstColorType) {

[scroggo, 2015/12/09 20:57:31]

Comment explaining why?

[msarett, 2015/12/10 15:19:26]

Done.

+        outInfo = SkImageInfo::MakeA8(scaledOutWidth, scaledOutHeight);
+    }
     bitmap->setInfo(outInfo);
     if (!bitmap->tryAllocPixels(allocator, colorTable.get())) {
         SkCodecPrintf("Error: Could not allocate pixels.\n");