Serialization of SkPictureImageFilter

include/core/SkPicture.h

 
 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPicture_DEFINED
@@ skipping 50 matching lines @@
      *  Recreate a picture that was serialized into a stream.
      *  @param SkStream Serialized picture data.
      *  @param proc Function pointer for installing pixelrefs on SkBitmaps representing the
      *              encoded bitmap data from the stream.
      *  @return A new SkPicture representing the serialized data, or NULL if the stream is
      *          invalid.
      */
     static SkPicture* CreateFromStream(SkStream*,
                                        InstallPixelRefProc proc = &SkImageDecoder::DecodeMemory);
 
+    /**
+     *  Recreate a picture that was serialized into a buffer.
+     *  @param SkReadBuffer Serialized picture data.
+     *  @return A new SkPicture representing the serialized data, or NULL if the buffer is
+     *          invalid.
+     */
+    static SkPicture* CreateFromBuffer(SkReadBuffer&);

[reed1, 2014/02/05 21:05:06]

Does this not need/want the same optional parameters as CreateFromStream?

[sugoi1, 2014/02/05 21:33:06]

I'm assuming you're talking about "InstallPixelRefProc proc =
&SkImageDecoder::DecodeMemory". So, this parameter is passed down like this :

SkPicture::CreateFromStream() down to
SkPicturePlayback::CreateFromStream() down to
SkPicturePlayback::parseStream() down to
SkPicturePlayback::parseStreamTag() down to
SkReadBuffer::setBitmapDecoder() (Inside the PICT_BUFFER_SIZE_TAG case)

Currently, the same sequence (if you replace "Stream" by "Buffer" in the
previous list of function names) does not encode/decode bitmaps, it just saves
the memory as is in the buffer, I believe, by using SkBitmap::flatten() so
there's no current need for a decoder (The same way
SkPicturePlayback::serialize() uses an encoder and SkPicturePlayback::flatten()
does not)

[scroggo, 2014/02/05 22:20:11]

This is almost true. In the case of a subclass of SkPixelRef() that implements
onRefEncodedData(), the encoded data is written instead of flattening the
SkBitmap (see SkWriteBuffer::writeBitmap()), and in general, such an SkPixelRef
cannot be flattened normally (see SkCachingPixelRef for an example).

When unflattening, you'll still need to decode images held in these types of
SkPixelRefs somehow.

+
     virtual ~SkPicture();
 
     /**
      *  Swap the contents of the two pictures. Guaranteed to succeed.
      */
     void swap(SkPicture& other);
 
     /**
      *  Creates a thread-safe clone of the picture that is ready for playback.
      */
@@ skipping 99 matching lines @@
     typedef SkData* (*EncodeBitmap)(size_t* pixelRefOffset, const SkBitmap& bm);
 
     /**
      *  Serialize to a stream. If non NULL, encoder will be used to encode
      *  any bitmaps in the picture.
      *  encoder will never be called with a NULL pixelRefOffset.
      */
     void serialize(SkWStream*, EncodeBitmap encoder = NULL) const;
 
     /**
+     *  Serialize to a buffer.
+     */
+    void flatten(SkWriteBuffer&) const;
+
+    /**
      * Returns true if any bitmaps may be produced when this SkPicture
      * is replayed.
      * Returns false if called while still recording.
      */
     bool willPlayBackBitmaps() const;
 
 #ifdef SK_BUILD_FOR_ANDROID
     /** Signals that the caller is prematurely done replaying the drawing
         commands. This can be called from a canvas virtual while the picture
         is drawing. Has no effect if the picture is not drawing.
@@ skipping 38 matching lines @@
 
     // For testing. Derived classes may instantiate an alternate
     // SkBBoxHierarchy implementation
     virtual SkBBoxHierarchy* createBBoxHierarchy() const;
 
     // Return true if the SkStream represents a serialized picture, and fills out
     // SkPictInfo. After this function returns, the SkStream is not rewound; it
     // will be ready to be parsed to create an SkPicturePlayback.
     // If false is returned, SkPictInfo is unmodified.
     static bool StreamIsSKP(SkStream*, SkPictInfo*);
+    static bool BufferIsSKP(SkReadBuffer&, SkPictInfo*);
 private:
     friend class SkFlatPicture;
     friend class SkPicturePlayback;
 
     typedef SkRefCnt INHERITED;
 };
 
 /**
  *  Subclasses of this can be passed to canvas.drawPicture. During the drawing
  *  of the picture, this callback will periodically be invoked. If its
  *  abortDrawing() returns true, then picture playback will be interrupted.
  *
  *  The resulting drawing is undefined, as there is no guarantee how often the
  *  callback will be invoked. If the abort happens inside some level of nested
  *  calls to save(), restore will automatically be called to return the state
  *  to the same level it was before the drawPicture call was made.
  */
 class SK_API SkDrawPictureCallback {
 public:
     SkDrawPictureCallback() {}
     virtual ~SkDrawPictureCallback() {}
 
     virtual bool abortDrawing() = 0;
 };
 
 #endif