composition.h Example File
^{demos/composition/composition.h}

 /****************************************************************************
 **
 ** Copyright (C) 2005-2007 Trolltech ASA. All rights reserved.
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
 ** This file may be used under the terms of the GNU General Public
 ** License version 2.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of
 ** this file.  Please review the following information to ensure GNU
 ** General Public Licensing requirements will be met:
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 ** review the following information:
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 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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 ****************************************************************************/

 #ifndef COMPOSITION_H
 #define COMPOSITION_H

 #include "arthurwidgets.h"

 #include <QPainter>
 #include <QEvent>

 class QPushButton;
 class QRadioButton;

 #ifdef QT_OPENGL_SUPPORT
 #include <QtOpenGL>
 #endif

 class CompositionWidget : public QWidget
 {
     Q_OBJECT

 public:
     CompositionWidget(QWidget *parent);

 public slots:
 void nextMode();

 private:
     bool m_cycle_enabled;

     QRadioButton *rbClear;
     QRadioButton *rbSource;
     QRadioButton *rbDest;
     QRadioButton *rbSourceOver;
     QRadioButton *rbDestOver;
     QRadioButton *rbSourceIn;
     QRadioButton *rbDestIn;
     QRadioButton *rbSourceOut;
     QRadioButton *rbDestOut;
     QRadioButton *rbSourceAtop;
     QRadioButton *rbDestAtop;
     QRadioButton *rbXor;
 };

 class CompositionRenderer : public ArthurFrame
 {
     Q_OBJECT

     enum ObjectType { NoObject, Circle, Rectangle, Image };

     Q_PROPERTY(int circleColor READ circleColor WRITE setCircleColor)
     Q_PROPERTY(int circleAlpha READ circleAlpha WRITE setCircleAlpha)
     Q_PROPERTY(bool animation READ animationEnabled WRITE setAnimationEnabled)

 public:
     CompositionRenderer(QWidget *parent);

     void paint(QPainter *);

     void mousePressEvent(QMouseEvent *);
     void mouseMoveEvent(QMouseEvent *);
     void mouseReleaseEvent(QMouseEvent *);

     void setCirclePos(const QPointF &pos) { m_circle_pos = pos; update(); }

     QSize sizeHint() const { return QSize(500, 400); }

     bool animationEnabled() const { return m_animation_enabled; }
     int circleColor() const { return m_circle_hue; }
     int circleAlpha() const { return m_circle_alpha; }

 public slots:
 void setClearMode() { m_composition_mode = QPainter::CompositionMode_Clear; update(); }
     void setSourceMode() { m_composition_mode = QPainter::CompositionMode_Source; update(); }
     void setDestMode() { m_composition_mode = QPainter::CompositionMode_Destination; update(); }
     void setSourceOverMode() { m_composition_mode = QPainter::CompositionMode_SourceOver; update(); }
     void setDestOverMode() { m_composition_mode = QPainter::CompositionMode_DestinationOver; update(); }
     void setSourceInMode() { m_composition_mode = QPainter::CompositionMode_SourceIn; update(); }
     void setDestInMode() { m_composition_mode = QPainter::CompositionMode_DestinationIn; update(); }
     void setSourceOutMode() { m_composition_mode = QPainter::CompositionMode_SourceOut; update(); }
     void setDestOutMode() { m_composition_mode = QPainter::CompositionMode_DestinationOut; update(); }
     void setSourceAtopMode() { m_composition_mode = QPainter::CompositionMode_SourceAtop; update(); }
     void setDestAtopMode() { m_composition_mode = QPainter::CompositionMode_DestinationAtop; update(); }
     void setXorMode() { m_composition_mode = QPainter::CompositionMode_Xor; update(); }

     void setCircleAlpha(int alpha) { m_circle_alpha = alpha; update(); }
     void setCircleColor(int hue) { m_circle_hue = hue; update(); }
     void setAnimationEnabled(bool enabled) { m_animation_enabled = enabled; update(); }

 private:
     void updateCirclePos();
     void drawBase(QPainter &p);
     void drawSource(QPainter &p);

     QPainter::CompositionMode m_composition_mode;

     QImage m_image;
     QImage m_buffer;
     QImage m_base_buffer;

     int m_circle_alpha;
     int m_circle_hue;

     QPointF m_circle_pos;
     QPointF m_offset;

     ObjectType m_current_object;
     bool m_animation_enabled;

 #ifdef QT_OPENGL_SUPPORT
     QGLPixelBuffer *m_pbuffer;
     GLuint m_base_tex;
     GLuint m_compositing_tex;
     int m_pbuffer_size; // width==height==size of pbuffer
     QSize m_previous_size;
 #endif
 };

 #endif // COMPOSITION_H