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#ifndef QVGIMAGEPOOL_P_H

#define QVGIMAGEPOOL_P_H

//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API.  It exists for the convenience

// of other Qt classes.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

//

#include "qvg.h"

#include <QtCore/qscopedpointer.h>

QT_BEGIN_NAMESPACE

class QVGPixmapData;

class QVGImagePoolPrivate;

class Q_OPENVG_EXPORT QVGImagePool

{

public:

    QVGImagePool();

    virtual ~QVGImagePool();

    static QVGImagePool *instance();

    // This function can be used from system-specific graphics system

    // plugins to alter the image allocation strategy.

    static void setImagePool(QVGImagePool *pool);

    // Create a new VGImage from the pool with the specified parameters

    // that is not associated with a pixmap.  The VGImage is returned to

    // the pool when releaseImage() is called.

    //

    // This function will call reclaimSpace() when vgCreateImage() fails.

    //

    // This function is typically called when allocating temporary

    // VGImage's for pixmap filters.  The "keepData" object will not

    // be reclaimed if reclaimSpace() needs to be called.

    virtual VGImage createTemporaryImage(VGImageFormat format,

                                         VGint width, VGint height,

                                         VGbitfield allowedQuality,

                                         QVGPixmapData *keepData = 0);

    // Create a new VGImage with the specified parameters and associate

    // it with "data".  The QVGPixmapData will be notified when the

    // VGImage needs to be reclaimed by the pool.

    //

    // This function will call reclaimSpace() when vgCreateImage() fails.

    virtual VGImage createImageForPixmap(VGImageFormat format,

                                         VGint width, VGint height,

                                         VGbitfield allowedQuality,

                                         QVGPixmapData *data);

    // Create a permanent VGImage with the specified parameters.

    // If there is insufficient space for the vgCreateImage call,

    // then this function will call reclaimSpace() and try again.

    //

    // The caller is responsible for calling vgDestroyImage()

    // when it no longer needs the VGImage, as the image is not

    // recorded in the image pool.

    //

    // This function is typically used for pattern brushes where

    // the OpenVG engine is responsible for managing the lifetime

    // of the VGImage, destroying it automatically when the brush

    // is no longer in use.

    virtual VGImage createPermanentImage(VGImageFormat format,

                                         VGint width, VGint height,

                                         VGbitfield allowedQuality);

    // Release a VGImage that is no longer required.

    virtual void releaseImage(QVGPixmapData *data, VGImage image);

    // Notify the pool that a QVGPixmapData object is using

    // an image again.  This allows the pool to move the image

    // within a least-recently-used list of QVGPixmapData objects.

    virtual void useImage(QVGPixmapData *data);

    // Notify the pool that the VGImage's associated with a

    // QVGPixmapData are being detached from the pool.  The caller

    // will become responsible for calling vgDestroyImage().

    virtual void detachImage(QVGPixmapData *data);

    // Reclaim space for an image allocation with the specified parameters.

    // Returns true if space was reclaimed, or false if there is no

    // further space that can be reclaimed.  The "data" parameter

    // indicates the pixmap that is trying to obtain space which should

    // not itself be reclaimed.

    virtual bool reclaimSpace(VGImageFormat format,

                              VGint width, VGint height,

                              QVGPixmapData *data);

    // Hibernate the image pool because the context is about to be

    // destroyed.  All VGImage's left in the pool should be released.

    virtual void hibernate();

protected:

    // Helper functions for managing the LRU list of QVGPixmapData objects.

    void moveToHeadOfLRU(QVGPixmapData *data);

    void removeFromLRU(QVGPixmapData *data);

    QVGPixmapData *pixmapLRU();

private:

    QScopedPointer<QVGImagePoolPrivate> d_ptr;

    Q_DECLARE_PRIVATE(QVGImagePool)

    Q_DISABLE_COPY(QVGImagePool)

};

QT_END_NAMESPACE

#endif