SkCachingPixelRef to use SkImageGenerator

src/lazy/SkCachingPixelRef.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCachingPixelRef_DEFINED
 #define SkCachingPixelRef_DEFINED
 
-#include "SkImage.h"
+#include "SkImageInfo.h"
+#include "SkImageGenerator.h"
 #include "SkPixelRef.h"
 
 class SkColorTable;
 
 /**
  *  PixelRef which defers decoding until SkBitmap::lockPixels() is
  *  called.  Caches the decoded images in the global
  *  SkScaledImageCache.  When the pixels are unlocked, this cache may
  *  or be destroyed before the next lock.  If so, onLockPixels will
  *  attempt to re-decode.
  *
- *  Decoding is handled by the pure-virtual functions onDecodeInfo()
- *  and onDecodePixels().  Subclasses of this class need only provide
- *  those two functions.
+ *  Decoding is handled by the SkImageGenerator
  */
 class SkCachingPixelRef : public SkPixelRef {
 public:
-    SkCachingPixelRef();
-    virtual ~SkCachingPixelRef();
+    /**
+     *  This created SkCachingPixelRef will take ownership of the

[scroggo, 2013/12/02 18:26:01]

Could you say that the SkCachingPixelRef is installed on dst?

+     *  SkImageGenerator and destroy it.
+     */
+    static bool Install(SkAutoTDelete<SkImageGenerator>* gen, SkBitmap* dst);

[scroggo, 2013/12/02 18:26:01]

Although I understand the motivation - it simplifies things for the caller, it
seems odd to me to pass the SkImageGenerator inside an SkAutoTDelete.

If we stick with the SkAutoTDelete, can you add a comment that gen is unchanged
on failure (i.e. still holds an SkImageGenerator)?

[hal.canary, 2013/12/04 23:06:41]

I ended up changing my mind on this.  Let's keep the interface similar to
SkDiscardablePixelRef::Install and make the comments very clear.

 
 protected:
+    virtual ~SkCachingPixelRef();
     virtual void* onLockPixels(SkColorTable** colorTable) SK_OVERRIDE;
     virtual void onUnlockPixels() SK_OVERRIDE;
     virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; }
-    virtual bool onImplementsDecodeInto() SK_OVERRIDE  { return true; }
-    virtual bool onDecodeInto(int pow2, SkBitmap*) SK_OVERRIDE;
 
-    /**
-     *  Configure the supplied bitmap for this pixelRef, based on
-     *  information provided by onDecodeInfo().  Does not set the
-     *  bitmap's pixelRef. */
-    bool configure(SkBitmap* bitmap);
-
-    /**
-     *  Cache info from onDecodeInfo(). Returns false on failure.
-     */
-    bool getInfo(SkImageInfo* info);
-
-    /**
-     *  Return some information about the pixels, allowing this class
-     *  to allocate pixels.  @return false if anything goes wrong.
-     */
-    virtual bool onDecodeInfo(SkImageInfo* info) = 0;
-    /**
-     *  Decode into the given pixels, a block of memory of size
-     *  (info.fHeight - 1) * rowBytes + (info.fWidth * bytesPerPixel)
-     *
-     *  @param info Should be identical to the info returned by
-     *         onDecodeInfo so that the implementation can confirm
-     *         that the caller knows what it is asking for (config,
-     *         size).  Thiscontract also allows the caller to specify
-     *         different output-configs, which the implementation can
-     *         decide to support or not.
-     *
-     *  @return false if anything goes wrong.
-     */
-    virtual bool onDecodePixels(const SkImageInfo& info,
-                                void* pixels,
-                                size_t rowBytes) = 0;
+    virtual SkData* onRefEncodedData() SK_OVERRIDE {
+        return fImageGenerator->refEncodedData();
+    }
+    // No need to flatten this object. When flattening an SkBitmap,
+    // SkOrderedWriteBuffer will check the encoded data and write that
+    // instead.
+    // Future implementations of SkFlattenableWriteBuffer will need to
+    // special case for onRefEncodedData as well.
+    SK_DECLARE_UNFLATTENABLE_OBJECT()
 
 private:
-    bool                        fErrorInDecoding;
-    void*                       fScaledCacheId;
-    SkImageInfo                 fInfo;
+    SkImageGenerator* fImageGenerator;
+    bool              fErrorInDecoding;
+    void*             fScaledCacheId;
+    SkImageInfo       fInfo;

[scroggo, 2013/12/02 18:26:01]

fInfo and fRowBytes can be const.

[hal.canary, 2013/12/04 23:06:41]

Done.

+    size_t            fRowBytes;
 
+    SkCachingPixelRef(SkImageGenerator* imageGenerator,
+                      const SkImageInfo& info,
+                      size_t rowBytes);
     typedef SkPixelRef INHERITED;
 };
 
 #endif  // SkCachingPixelRef_DEFINED