composition.h Example File

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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;

      QRadioButton *rbPlus;
      QRadioButton *rbMultiply;
      QRadioButton *rbScreen;
      QRadioButton *rbOverlay;
      QRadioButton *rbDarken;
      QRadioButton *rbLighten;
      QRadioButton *rbColorDodge;
      QRadioButton *rbColorBurn;
      QRadioButton *rbHardLight;
      QRadioButton *rbSoftLight;
      QRadioButton *rbDifference;
      QRadioButton *rbExclusion;
  };

  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 *) override;

      void setCirclePos(const QPointF &pos);

      QSize sizeHint() const override { 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; }

  protected:
      void mousePressEvent(QMouseEvent *) override;
      void mouseMoveEvent(QMouseEvent *) override;
      void mouseReleaseEvent(QMouseEvent *) override;
      void timerEvent(QTimerEvent *) override;

  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 setPlusMode() { m_composition_mode = QPainter::CompositionMode_Plus; update(); }
      void setMultiplyMode() { m_composition_mode = QPainter::CompositionMode_Multiply; update(); }
      void setScreenMode() { m_composition_mode = QPainter::CompositionMode_Screen; update(); }
      void setOverlayMode() { m_composition_mode = QPainter::CompositionMode_Overlay; update(); }
      void setDarkenMode() { m_composition_mode = QPainter::CompositionMode_Darken; update(); }
      void setLightenMode() { m_composition_mode = QPainter::CompositionMode_Lighten; update(); }
      void setColorDodgeMode() { m_composition_mode = QPainter::CompositionMode_ColorDodge; update(); }
      void setColorBurnMode() { m_composition_mode = QPainter::CompositionMode_ColorBurn; update(); }
      void setHardLightMode() { m_composition_mode = QPainter::CompositionMode_HardLight; update(); }
      void setSoftLightMode() { m_composition_mode = QPainter::CompositionMode_SoftLight; update(); }
      void setDifferenceMode() { m_composition_mode = QPainter::CompositionMode_Difference; update(); }
      void setExclusionMode() { m_composition_mode = QPainter::CompositionMode_Exclusion; update(); }

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

  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;
      int m_animationTimer;

  #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