move erase into SkPixmap

include/core/SkPixmap.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPixmap_DEFINED
 #define SkPixmap_DEFINED
 
@@ skipping 115 matching lines @@
     bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes) const {
         return this->readPixels(dstInfo, dstPixels, dstRowBytes, 0, 0);
     }
     bool readPixels(const SkPixmap& dst, int srcX, int srcY) const {
         return this->readPixels(dst.info(), dst.writable_addr(), dst.rowBytes(), srcX, srcY);
     }
     bool readPixels(const SkPixmap& dst) const {
         return this->readPixels(dst.info(), dst.writable_addr(), dst.rowBytes(), 0, 0);
     }
 
+    /**
+     *  Returns true if pixels were written to (e.g. if colorType is kUnknown_SkColorType, this
+     *  will return false). If subset does not intersect the bounds of this pixmap, returns false.
+     */
+    bool erase(SkColor, const SkIRect& subset) const;
+
+    bool erase(SkColor color) const { return this->erase(color, this->bounds()); }
+
 private:
     const void*     fPixels;
     SkColorTable*   fCTable;
     size_t          fRowBytes;
     SkImageInfo     fInfo;
 };
 
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 class SkAutoPixmapStorage : public SkPixmap {
@@ skipping 12 matching lines @@
 
     /**
      *  Allocate memory for the pixels needed to match the specified Info and fill out the pixmap
      *  to point to that memory. The storage will be freed when this object is destroyed,
      *  or if another call to tryAlloc() or alloc() is made.
      *
      *  If the memory cannot be allocated, calls sk_throw().
      */
     void alloc(const SkImageInfo&);
 
+    // We wrap these so we can clear our internal storage
+
+    void reset() {
+        this->freeStorage();
+        this->INHERITED::reset();
+    }
+    void reset(const SkImageInfo& info, const void* addr, size_t rb, SkColorTable* ctable = NULL) {
+        this->freeStorage();
+        this->INHERITED::reset(info, addr, rb, ctable);
+    }
+    void reset(const SkImageInfo& info) {
+        this->freeStorage();
+        this->INHERITED::reset(info);
+    }
+    bool SK_WARN_UNUSED_RESULT reset(const SkMask& mask) {
+        this->freeStorage();
+        return this->INHERITED::reset(mask);
+    }
+
 private:
     void*   fStorage;
+
+    void freeStorage() {
+        sk_free(fStorage);
+        fStorage = NULL;
+    }
+
+    typedef SkPixmap INHERITED;
 };
 
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 class SkAutoPixmapUnlock : ::SkNoncopyable {
 public:
     SkAutoPixmapUnlock() : fUnlockProc(NULL), fIsLocked(false) {}
     SkAutoPixmapUnlock(const SkPixmap& pm, void (*unlock)(void*), void* ctx)
         : fUnlockProc(unlock), fUnlockContext(ctx), fPixmap(pm), fIsLocked(true)
     {}
@@ skipping 31 matching lines @@
 private:
     void        (*fUnlockProc)(void*);
     void*       fUnlockContext;
     SkPixmap    fPixmap;
     bool        fIsLocked;
 
     friend class SkBitmap;
 };
 
 #endif