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:

[robertphillips, 2014/07/21 16:07:19]

I don't think you need the 'fBlitMemory(0)' anymore.

[krajcevski, 2014/07/21 16:42:08]

Done.

I stopped reading at the explicit declaration on the SkAutoMalloc constructor.
:P

+    SkBlitter() : fBlitMemory(0) { }
     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.
+     */
+    virtual void* allocBlitMemory(size_t sz) {
+        return fBlitMemory.reset(sz, SkAutoMalloc::kReuse_OnShrink);
+    }
+
     ///@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:
+
+    SkAutoMalloc 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 19 matching lines @@
     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;
     virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE;
     virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE;
     virtual void blitAntiRect(int x, int y, int width, int height,
                      SkAlpha leftAlpha, SkAlpha rightAlpha) SK_OVERRIDE;
     virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE;
     virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE;
 
+    virtual void* allocBlitMemory(size_t sz) SK_OVERRIDE {
+        return fBlitter->allocBlitMemory(sz);
+    }
+
 private:
     SkBlitter*  fBlitter;
     SkIRect     fClipRect;
 };
 
 /** Wraps another (real) blitter, and ensures that the real blitter is only
     called with coordinates that have been clipped by the specified clipRgn.
     This means the caller need not perform the clipping ahead of time.
 */
 class SkRgnClipBlitter : public SkBlitter {
 public:
     void init(SkBlitter* blitter, const SkRegion* clipRgn) {
         SkASSERT(clipRgn && !clipRgn->isEmpty());
         fBlitter = blitter;
         fRgn = clipRgn;
     }
 
     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;
     virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE;
     virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE;
     virtual void blitAntiRect(int x, int y, int width, int height,
                      SkAlpha leftAlpha, SkAlpha rightAlpha) SK_OVERRIDE;
     virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE;
     virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE;
 
+    virtual void* allocBlitMemory(size_t sz) SK_OVERRIDE {
+        return fBlitter->allocBlitMemory(sz);
+    }
+
 private:
     SkBlitter*      fBlitter;
     const SkRegion* fRgn;
 };
 
 /** Factory to set up the appropriate most-efficient wrapper blitter
     to apply a clip. Returns a pointer to a member, so lifetime must
     be managed carefully.
 */
 class SkBlitterClipper {
 public:
     SkBlitter*  apply(SkBlitter* blitter, const SkRegion* clip,
                       const SkIRect* bounds = NULL);
 
 private:
     SkNullBlitter       fNullBlitter;
     SkRectClipBlitter   fRectBlitter;
     SkRgnClipBlitter    fRgnBlitter;
 };
 
 #endif