SkScaledCodec class

include/codec/SkScaledCodec.h

+/*
+ * 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 "SkColorTable.h"
+#include "SkEncodedFormat.h"
+#include "SkImageInfo.h"
+#include "SkRefCnt.h"
+#include "SkSwizzler.h"
+#include "SkCodec_libpng.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 get_sample_size(int srcDimension, int dstDimension) {

[scroggo, 2015/07/31 13:35:33]

style nit: Skia has different conventions for static functions and static member
functions. While we name static functions get_sample_size, we name static member
functions GetSampleSize.

[emmaleer, 2015/07/31 18:41:56]

Acknowledged.

+        SkASSERT(dstDimension <= srcDimension);
+        return srcDimension / dstDimension;
+    }   
+
+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{
+        return fCodec->reallyHasAlpha();
+    }
+
+private:
+    SkAutoTDelete<SkCodec>   fCodec;
+
+    SkScaledCodec(SkCodec*);
+
+
+    typedef SkCodec INHERITED;
+};
+#endif // SkScaledCodec_DEFINED