Plug & Paint Example | Qt Widgets 5.13.0

Qt 5.13 | Qt Widgets | Plug & Paint Example

Qt 5.13.0 Reference Documentation

# Plug & Paint Example

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      #ifndef PAINTAREA_H
      #define PAINTAREA_H

      #include <QColor>
      #include <QImage>
      #include <QPainterPath>
      #include <QWidget>

      class BrushInterface;

      class PaintArea : public QWidget
      {
          Q_OBJECT

      public:
          PaintArea(QWidget *parent = nullptr);

          bool openImage(const QString &fileName);
          bool saveImage(const QString &fileName, const char *fileFormat);
          void setImage(const QImage &image);
          void insertShape(const QPainterPath &path);
          void setBrushColor(const QColor &color);
          void setBrushWidth(int width);
          void setBrush(BrushInterface *brushInterface, const QString &brush);

          QImage image() const { return theImage; }
          QColor brushColor() const { return color; }
          int brushWidth() const { return thickness; }
          QSize sizeHint() const override;

      protected:
          void paintEvent(QPaintEvent *event) override;
          void mousePressEvent(QMouseEvent *event) override;
          void mouseMoveEvent(QMouseEvent *event) override;
          void mouseReleaseEvent(QMouseEvent *event) override;

      private:
          void setupPainter(QPainter &painter);

          QImage theImage = {500, 400, QImage::Format_RGB32};
          QColor color = Qt::blue;
          int thickness = 3;

          BrushInterface *brushInterface = nullptr;
          QString brush;
          QPoint lastPos = {-1, -1};

          QPainterPath pendingPath;
      };

      #endif