Let blitters be notified when they're done being used

src/core/SkBlitter.h

 
 /*
  * Copyright 2006 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 SkBlitter_DEFINED
 #define SkBlitter_DEFINED
 
 #include "SkBitmap.h"
 #include "SkBitmapProcShader.h"
 #include "SkMask.h"
 #include "SkMatrix.h"
 #include "SkPaint.h"
 #include "SkRefCnt.h"
 #include "SkRegion.h"
 #include "SkShader.h"
 #include "SkSmallAllocator.h"
 
 /** SkBlitter and its subclasses are responsible for actually writing pixels
     into memory. Besides efficiency, they handle clipping and antialiasing.
 */
 class SkBlitter {
 public:
+    SkBlitter() : fBlitMemory(NULL) { }
     virtual ~SkBlitter();
 
     /// Blit a horizontal run of one or more pixels.
     virtual void blitH(int x, int y, int width);
     /// Blit a horizontal run of antialiased pixels; runs[] is a *sparse*
     /// zero-terminated run-length encoding of spans of constant alpha values.
     virtual void blitAntiH(int x, int y, const SkAlpha antialias[],
                            const int16_t runs[]);
 
     /// Blit a vertical run of pixels with a constant alpha value.
@@ skipping 31 matching lines @@
     virtual SkShader::Context* getShaderContext() const;
 
     /**
      * Special methods for blitters that can blit more than one row at a time.
      * This function returns the number of rows that this blitter could optimally
      * process at a time. It is still required to support blitting one scanline
      * at a time.
      */
     virtual int requestRowsPreserved() const { return 1; }
 
+    /**
+     * This function allocates memory for the blitter that the blitter then owns.
+     * The memory can be used by the calling function at will, but it will be
+     * released when the blitter's destructor is called. This function returns
+     * NULL if no persistent memory is needed by the blitter.
+     */
+    void* allocBlitMemory(size_t);
+
     ///@name non-virtual helpers
     void blitMaskRegion(const SkMask& mask, const SkRegion& clip);
     void blitRectRegion(const SkIRect& rect, const SkRegion& clip);
     void blitRegion(const SkRegion& clip);
     ///@}
 
     /** @name Factories
         Return the correct blitter to use given the specified context.
      */
     static SkBlitter* Choose(const SkBitmap& device,
                              const SkMatrix& matrix,
                              const SkPaint& paint,
                              SkTBlitterAllocator*,
                              bool drawCoverage = false);
 
     static SkBlitter* ChooseSprite(const SkBitmap& device,
                                    const SkPaint&,
                                    const SkBitmap& src,
                                    int left, int top,
                                    SkTBlitterAllocator*);
     ///@}
 
+protected:
+
+    void* fBlitMemory;
+    
 private:
 };
 
 /** This blitter silently never draws anything.
 */
 class SkNullBlitter : public SkBlitter {
 public:
     virtual void blitH(int x, int y, int width) SK_OVERRIDE;
     virtual void blitAntiH(int x, int y, const SkAlpha[],
                            const int16_t runs[]) SK_OVERRIDE;
@@ skipping 67 matching lines @@
     SkBlitter*  apply(SkBlitter* blitter, const SkRegion* clip,
                       const SkIRect* bounds = NULL);
 
 private:
     SkNullBlitter       fNullBlitter;
     SkRectClipBlitter   fRectBlitter;
     SkRgnClipBlitter    fRgnBlitter;
 };
 
 #endif