SkScaledCodec class

src/codec/SkCodec_libpng.cpp

Index: src/codec/SkCodec_libpng.cpp
diff --git a/src/codec/SkCodec_libpng.cpp b/src/codec/SkCodec_libpng.cpp
index 553233de12117ea8ccebcdfd261a720b8e721412..a03deb435f41d625327eebf75bf21c2c13fb0f52 100644
--- a/src/codec/SkCodec_libpng.cpp
+++ b/src/codec/SkCodec_libpng.cpp
@@ -424,6 +424,11 @@ static bool conversion_possible(const SkImageInfo& dst, const SkImageInfo& src)
     }
 }
 
+bool SkPngCodec::onIsInterlaced() {
+    // we cannot depend on fNumberPasses, since it may not have been set yet

[scroggo, 2015/07/27 19:29:57]

If we moved this onto the scanline decoder, we would already know it.

[emmaleer, 2015/07/28 14:19:16]

Acknowledged.

+    return 1 != png_set_interlace_handling(fPng_ptr); 
+}
+
 SkCodec::Result SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
                                                void* dst, size_t rowBytes,
                                                const Options& options,
@@ -593,14 +598,19 @@ SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void*
 class SkPngScanlineDecoder : public SkScanlineDecoder {
 public:
     SkPngScanlineDecoder(const SkImageInfo& dstInfo, SkPngCodec* codec)
-        : INHERITED(dstInfo)
+        : INHERITED(dstInfo, codec->getInfo())
         , fCodec(codec)
         , fHasAlpha(false)
     {
-        fStorage.reset(dstInfo.width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig));
+        fStorage.reset(fCodec->getInfo().width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig));
         fSrcRow = static_cast<uint8_t*>(fStorage.get());
     }
 
+    bool onSetSampleX(int sampleX) override {
+        fCodec->fSwizzler->setSampleX(sampleX);
+        return true;
+    }
+
     SkCodec::Result onGetScanlines(void* dst, int count, size_t rowBytes) override {
         if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) {
             SkCodecPrintf("setjmp long jump!\n");
@@ -647,17 +657,22 @@ private:
 class SkPngInterlacedScanlineDecoder : public SkScanlineDecoder {
 public:
     SkPngInterlacedScanlineDecoder(const SkImageInfo& dstInfo, SkPngCodec* codec)
-        : INHERITED(dstInfo)
+        : INHERITED(dstInfo, codec->getInfo())
         , fCodec(codec)
         , fHasAlpha(false)
         , fCurrentRow(0)
         , fHeight(dstInfo.height())
     {
-        fSrcRowBytes = dstInfo.width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig);
+        fSrcRowBytes = codec->getInfo().width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig);
         fGarbageRow.reset(fSrcRowBytes);
         fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get());
     }
 
+    bool onSetSampleX(int sampleX) override {
+        fCodec->fSwizzler->setSampleX(sampleX);
+        return true;
+    }
+
     SkCodec::Result onGetScanlines(void* dst, int count, size_t dstRowBytes) override {
         //rewind stream if have previously called onGetScanlines, 
         //since we need entire progressive image to get scanlines
@@ -728,8 +743,11 @@ SkScanlineDecoder* SkPngCodec::onGetScanlineDecoder(const SkImageInfo& dstInfo,
         return NULL;
     }
     // Check to see if scaling was requested.
-    if (dstInfo.dimensions() != this->getInfo().dimensions()) {
-        return NULL;
+    if(options.fSampled == false) {

[msarett, 2015/07/27 20:42:18]

I think we should still be able to check for invalid dimensions, based on the
sample size.

[emmaleer, 2015/07/28 14:19:16]

Yes, I now check to make sure dstHeight == srcHeight, and dstWidth = srcWidth /
SampleX

+        // If the caller is sampling, it is okay for the dimensions to not match
+        if (dstInfo.dimensions() != this->getInfo().dimensions()) {
+            return NULL;
+        }
     }
     // Create a new SkPngCodec, to be owned by the scanline decoder.
     SkStream* stream = this->stream()->duplicate();