SkMultiPictureDraw API

include/core/SkMultiPictureDraw.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkMultiPictureDraw_DEFINED
+#define SkMultiPictureDraw_DEFINED
+
+#include "SkMatrix.h"
+#include "SkTDArray.h"
+
+class SkCanvas;
+class SkPaint;
+class SkPicture;
+
+/** \class SkMultiPictureDraw
+
+    The MultiPictureDraw object accepts several picture/canvas pairs and
+    then attempts to optimally draw the pictures into the canvases, sharing
+    as many resources as possible.
+*/
+class SK_API SkMultiPictureDraw {
+public:
+    /**
+     *  Create an object to optimize the drawing of multiple pictures.
+     *  @param reserve Hint for the number of add calls expected to be issued
+     */
+    SkMultiPictureDraw(int reserve = 0);
+    ~SkMultiPictureDraw() { this->reset(); }
+
+    /**
+     *  Add a canvas/picture pair for later rendering.
+     *  @param canvas   the canvas in which to draw picture
+     *  @param picture  the picture to draw into canvas
+     *  @param matrix   if non-NULL, applied to the CTM when drawing
+     *  @param paint    if non-NULL, draw picture to a temporary buffer
+     *                  and then apply the paint when the result is drawn
+     */
+    void add(SkCanvas* canvas,
+             const SkPicture* picture,
+             const SkMatrix* matrix = NULL, 
+             const SkPaint* paint = NULL);
+
+    /**
+     *  Perform all the previously added draws. This will reset the state
+     *  of this object.
+     */
+    void draw();
+
+    /**
+     *  Abandon all buffered draws and reset to the initial state.
+     */
+    void reset();
+
+private:
+    struct DrawData {
+        SkCanvas*        canvas;  // reffed
+        const SkPicture* picture; // reffed
+        SkMatrix         matrix;
+        SkPaint*         paint;   // owned
+    };
+
+    SkTDArray<DrawData> fDrawData;
+};
+
+#endif