source: trunk/src/opengl/gl2paintengineex/qglgradientcache_p.h@ 485

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//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QMultiHash>
#include <QObject>
#include <QtOpenGL>

class QGLGradientCache : public QObject
{
    Q_OBJECT
    struct CacheInfo
    {
        inline CacheInfo(QGradientStops s, qreal op, QGradient::InterpolationMode mode) :
            stops(s), opacity(op), interpolationMode(mode) {}

        GLuint texId;
        QGradientStops stops;
        qreal opacity;
        QGradient::InterpolationMode interpolationMode;
    };

    typedef QMultiHash<quint64, CacheInfo> QGLGradientColorTableHash;

public:
    QGLGradientCache() : QObject(), buffer_ctx(0)
    {
/*
        connect(QGLSignalProxy::instance(),
                SIGNAL(aboutToDestroyContext(const QGLContext *)),
                SLOT(cleanupGLContextRefs(const QGLContext *)));
*/
    }

    GLuint getBuffer(const QGradient &gradient, qreal opacity, const QGLContext *ctx);
    inline int paletteSize() const { return 1024; }

protected:
    inline int maxCacheSize() const { return 60; }
    inline void generateGradientColorTable(const QGradient& gradient,
                                           uint *colorTable,
                                           int size, qreal opacity) const;
    GLuint addCacheElement(quint64 hash_val, const QGradient &gradient, qreal opacity);

    void cleanCache();

    QGLGradientColorTableHash cache;
    const QGLContext *buffer_ctx;

public slots:
    void cleanupGLContextRefs(const QGLContext *context) {
        if (context == buffer_ctx) {
            cleanCache();
            buffer_ctx = 0;
        }
    }
};