include/graphics/SkBitmapRef.h

/* include/graphics/SkBitmapRef.h
**
** Copyright 2006, Google Inc.
**
** Licensed under the Apache License, Version 2.0 (the "License"); 
** you may not use this file except in compliance with the License. 
** You may obtain a copy of the License at 
**
**     http://www.apache.org/licenses/LICENSE-2.0 
**
** Unless required by applicable law or agreed to in writing, software 
** distributed under the License is distributed on an "AS IS" BASIS, 
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
** See the License for the specific language governing permissions and 
** limitations under the License.
*/

#ifndef SkBitmapRef_DEFINED
#define SkBitmapRef_DEFINED 

#include "SkBitmap.h"

class SkStream;

/** Helper class to manage a cache of decoded images from the file system
*/
class SkBitmapRef : public SkRefCnt {
public:
    /** Create a non-cached bitmap, trasfering ownership of pixels if needed
     */
    SkBitmapRef(const SkBitmap& src, bool transferOwnsPixels);
    virtual ~SkBitmapRef();

    const SkBitmap& bitmap();

    static SkBitmapRef* create(const SkBitmap& src, bool transferOwnsPixels);
    static SkBitmapRef* DecodeFile(const char file[], bool forceDecode);
    static SkBitmapRef* DecodeMemory(const void* bytes, size_t len, const char* name = NULL);
    static SkBitmapRef* DecodeStream(SkStream* stream, const char* name = NULL); 
    
    /** Frees all cached images, asserting that all references have been removed
    */
    static void PurgeCacheAll();

    /** frees one cached image, returning true, or returns false if none could be freed
    */
    static bool PurgeCacheOne();

private:
    struct Rec;
    Rec*    fRec;

    SkBitmapRef(Rec*);

    friend class SkBitmapRef_Globals;
};

class SkAutoBitmapRef {
public:
    SkAutoBitmapRef(const char file[], bool forceDecode)
    {
        fRef = SkBitmapRef::DecodeFile(file, forceDecode);
    }
    ~SkAutoBitmapRef() { delete fRef; }

    const SkBitmap* bitmap() const
    {
        return fRef ? &fRef->bitmap() : nil;
    }
private:
    SkBitmapRef*    fRef;
};


#endif