tabletcanvas.h Example File

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 #ifndef TABLETCANVAS_H
 #define TABLETCANVAS_H

 #include <QWidget>
 #include <QPixmap>
 #include <QPoint>
 #include <QTabletEvent>
 #include <QColor>
 #include <QBrush>
 #include <QPen>
 #include <QPoint>

 class QPaintEvent;
 class QString;

 class TabletCanvas : public QWidget
 {
     Q_OBJECT

 public:
     enum Valuator { PressureValuator, TangentialPressureValuator,
                     TiltValuator, VTiltValuator, HTiltValuator, NoValuator };
     Q_ENUM(Valuator)

     TabletCanvas();

     bool saveImage(const QString &file);
     bool loadImage(const QString &file);
     void clear();
     void setAlphaChannelValuator(Valuator type)
         { m_alphaChannelValuator = type; }
     void setColorSaturationValuator(Valuator type)
         { m_colorSaturationValuator = type; }
     void setLineWidthType(Valuator type)
         { m_lineWidthValuator = type; }
     void setColor(const QColor &c)
         { if (c.isValid()) m_color = c; }
     QColor color() const
         { return m_color; }
     void setTabletDevice(QTabletEvent *event)
         { updateCursor(event); }
     int maximum(int a, int b)
         { return a > b ? a : b; }

 protected:
     void tabletEvent(QTabletEvent *event) override;
     void paintEvent(QPaintEvent *event) override;
     void resizeEvent(QResizeEvent *event) override;

 private:
     void initPixmap();
     void paintPixmap(QPainter &painter, QTabletEvent *event);
     Qt::BrushStyle brushPattern(qreal value);
     static qreal pressureToWidth(qreal pressure);
     void updateBrush(const QTabletEvent *event);
     void updateCursor(const QTabletEvent *event);

     Valuator m_alphaChannelValuator;
     Valuator m_colorSaturationValuator;
     Valuator m_lineWidthValuator;
     QColor m_color;
     QPixmap m_pixmap;
     QBrush m_brush;
     QPen m_pen;
     bool m_deviceDown;

     struct Point {
         QPointF pos;
         qreal pressure;
         qreal rotation;
     } lastPoint;
 };

 #endif