initial preroll api

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
 #define SkPicture_DEFINED
@@ skipping 153 matching lines @@
      *  Serialize to a buffer.
      */
     void flatten(SkWriteBuffer&) const;
 
     /**
      * Returns true if any bitmaps may be produced when this SkPicture
      * is replayed.
      */
     bool willPlayBackBitmaps() const;
 
+    /**
+     *  This is a general hint that the picture will (soon) be drawn into a SkCanvas with
+     *  corresponding attributes (e.g. clip, matrix, props). No drawing occurs, but some
+     *  expensive operations may be run (e.g. image decoding).
+     *
+     *  Any of the parameters may be NULL.
+     *
+     *  @param srcBounds If not NULL, this is the subset of the picture (in the same coordinates
+     *                   as the picture's bounds) that preroll() should focus on.
+     *  @param initialMatrix If not NULL, this is the initialMatrix that is expected when the
+     *                       picture is actually drawn.
+     *  @param props If not NULL, these are the expected props when the picture is actually drawn.
+     */
+    void preroll(const SkRect* srcBounds, const SkMatrix* initialMatrix, const SkSurfaceProps*,
+                 void* gpuCacheAccessor) const;
+
     /** Return true if the SkStream/Buffer represents a serialized picture, and
         fills out SkPictInfo. After this function returns, the data source is not
         rewound so it will have to be manually reset before passing to
         CreateFromStream or CreateFromBuffer. Note, CreateFromStream and
         CreateFromBuffer perform this check internally so these entry points are
         intended for stand alone tools.
         If false is returned, SkPictInfo is unmodified.
     */
     static bool InternalOnly_StreamIsSKP(SkStream*, SkPictInfo*);
     static bool InternalOnly_BufferIsSKP(SkReadBuffer*, SkPictInfo*);
@@ skipping 123 matching lines @@
 
     friend class SkPictureRecorder;            // SkRecord-based constructor.
     friend class GrLayerHoister;               // access to fRecord
     friend class ReplaceDraw;
     friend class SkPictureUtils;
     friend class SkRecordedDrawable;
 };
 SK_COMPILE_ASSERT(sizeof(SkPicture) <= 96, SkPictureSize);
 
 #endif