Add a means of extracting active operations from SkPicture

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 130 matching lines @@
         not active. This does not alter the refcnt on the canvas (if present).
     */
     SkCanvas* getRecordingCanvas() const;
     /** Signal that the caller is done recording. This invalidates the canvas
         returned by beginRecording/getRecordingCanvas, and prepares the picture
         for drawing. Note: this happens implicitly the first time the picture
         is drawn.
     */
     void endRecording();
 
+    // An OperationList encapsulates a set of operation offsets into the picture byte
+    // stream along with the CTMs needed for those operation.
+    class OperationList : public SkNoncopyable {

[reed1, 2014/03/14 18:28:32]

does this class need to be public? Can it instead be private but declare our
impl as a friend?

[robertphillips, 2014/03/14 18:36:08]

SkPicturePlayback provides the impl and is already a friend. SkGpuDevice needs
to access the information and is pretty far away.

[robertphillips, 2014/03/14 19:23:23]

Done.

+    public:
+        // If valid returns false then there is no optimization data
+        // present. All the draw operations need to be issued.
+        virtual bool valid() const { return false; }
+
+        // The following three entry points should only be accessed if
+        // 'valid' returns true.
+        virtual int numOps() const { SkASSERT(false); return 0; };
+        // The offset in the picture of the operation to execute.
+        virtual uint32_t offset(int index) const { SkASSERT(false); return 0; };
+        // The CTM that must be installed for the operation to behave correctly
+        virtual const SkMatrix& matrix(int index) const { SkASSERT(false); return SkMatrix::I(); }
+
+        static const OperationList& InvalidList();
+
+    private:
+        typedef SkNoncopyable INHERITED;
+    };
+
+    /** PRIVATE / EXPERIMENTAL -- do not call
+        Return the operations required to render the content inside 'queryRect'.
+    */
+    const OperationList& EXPERIMENTAL_getActiveOps(const SkIRect& queryRect);
+
     /** Replays the drawing commands on the specified canvas. This internally
         calls endRecording() if that has not already been called.
         @param canvas the canvas receiving the drawing commands.
     */
     void draw(SkCanvas* canvas, SkDrawPictureCallback* = NULL);
 
     /** Return the width of the picture's recording canvas. This
         value reflects what was passed to setSize(), and does not necessarily
         reflect the bounds of what has been recorded into the picture.
         @return the width of the picture's recording canvas
@@ skipping 134 matching lines @@
  */
 class SK_API SkDrawPictureCallback {
 public:
     SkDrawPictureCallback() {}
     virtual ~SkDrawPictureCallback() {}
 
     virtual bool abortDrawing() = 0;
 };
 
 #endif