SkScaledCodec class

include/codec/SkScaledCodec.h

Index: include/codec/SkScaledCodec.h
diff --git a/include/codec/SkScaledCodec.h b/include/codec/SkScaledCodec.h
new file mode 100644
index 0000000000000000000000000000000000000000..0e9abedea49505e73e10c12f1a7343cde610bf87
--- /dev/null
+++ b/include/codec/SkScaledCodec.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SkScaledCodec_DEFINED
+#define SkScaledCodec_DEFINED
+
+#include "SkCodec.h"
+#include "SkScanlineDecoder.h"
+
+class SkScanlineDecoder;
+class SkStream;
+
+class SkScaledCodec : public SkCodec {
+public:
+    static SkCodec* NewFromStream(SkStream*);
+    static SkCodec* NewFromData(SkData*);
+
+    virtual ~SkScaledCodec();
+
+    // returns a sample size based on the input src and dst dimensions
+    // can only down sample, so dstDimension must be <= than srcDimension
+    static int GetSampleSize(int srcDimension, int dstDimension) {
+        SkASSERT(dstDimension <= srcDimension);
+        return srcDimension / dstDimension;
+    }
+    static bool DimensionsSupportedForSampling(const SkImageInfo& srcInfo, 

[scroggo, 2015/07/31 19:31:58]

nit: newline between functions.

[emmaleer, 2015/07/31 20:43:09]

Acknowledged.

+                                               const SkImageInfo& dstInfo){

[scroggo, 2015/07/31 19:31:58]

nit: space between ) and {

[emmaleer, 2015/07/31 20:43:09]

Acknowledged.

+        // heights must be equal as no native y sampling is supported
+        if (dstInfo.height() != srcInfo.height()) {
+            return false;
+        }
+        // only support down sampling, dstWidth cannot be larger that srcWidth
+        if(dstInfo.width() > srcInfo.width()) {
+            return false;
+        }
+        return true;   
+    }
+
+protected:
+    // Recommend a set of destination dimensions given a requested scale
+    SkISize onGetScaledDimensions(float desiredScale) const override;
+
+    Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, SkPMColor*, int*)
+            override;
+    SkEncodedFormat onGetEncodedFormat() const override{
+        return fCodec->getEncodedFormat();
+    }
+
+    SkScanlineDecoder* onGetScanlineDecoder(const SkImageInfo& dstInfo, const Options& options,
+                                            SkPMColor ctable[], int* ctableCount) override {
+        return fCodec->getScanlineDecoder(dstInfo, &options, ctable, ctableCount);
+    }
+    bool onReallyHasAlpha() const override{

[scroggo, 2015/07/31 19:31:58]

nit: There should be a newline before this method.

[emmaleer, 2015/07/31 20:43:09]

Acknowledged.

+        return fCodec->reallyHasAlpha();
+    }
+
+private:
+    SkAutoTDelete<SkCodec>   fCodec;
+
+    SkScaledCodec(SkCodec*);
+
+

[scroggo, 2015/07/31 19:31:58]

nit: Unnecessary newline.

[emmaleer, 2015/07/31 20:43:09]

Acknowledged.

+    typedef SkCodec INHERITED;
+};
+#endif // SkScaledCodec_DEFINED