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Lts/Common/LtsWidgets/LtsImageCropper/lts_image_cropper.h

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+/*
+ * @RDE_HEADER@
+ * graphicsview widget to resize qpixmaps/qimages with mouse drag and mwheel
+ * $Id$
+ * $HeadURL$
+ * $Author$
+ * Created by Jens Heilmann, SLTE, 2020-10-14
+ */
+
+#pragma once
+
+#include "lts_widgets_export.h"
+#include <QGraphicsView>
+
+namespace LtsWidgets
+{
+
+/**
+ * @brief The ImageCropper class provides a graphicsview widget to crop images with mouse drag and mwheel scroll.
+ *        avatar() returns a pixmap of the current view (the cropped image).
+ */
+class LTSWIDGETS_EXPORT LtsImageCropper : public QGraphicsView
+{
+
+  Q_OBJECT
+
+  Q_PROPERTY(QPixmap  pixMap     READ pixmap     WRITE setPixmap)
+  Q_PROPERTY(double   multiplier READ multiplier WRITE setMultiplier)
+  Q_PROPERTY(double   maxZoom    READ maxZoom    WRITE setMaxZoom)
+
+public:
+  /**
+    * @brief ImageCropper
+    * @param parent
+    * @param size specifies the size of the graphicsview widget, aswell as the size of the cropped image.
+    * @param image to crop
+    */
+  LtsImageCropper(QWidget *parent = nullptr, const QSize &size = {} , const QPixmap &pixmap = {});
+  ~LtsImageCropper();
+
+  /**
+   * @brief setter for image
+   * @param image
+   */
+  void setPixmap(const QPixmap &pixmap);
+
+  /**
+   * @brief setter for image
+   * @param image
+   */
+  void setImage(const QImage &image);
+
+  /**
+   * @brief set the zoom mutliplier for mwheel scaling e.g. 1.03.
+   * @param multiplier
+   */
+  void setMultiplier(double multiplier);
+
+  /**
+   * @brief set the maximum zoom in scale e.g. 2.0 = 200% zoom in.
+   * @param maxZoom
+   */
+  void setMaxZoom(double maxZoom) { m_maxScale = maxZoom; }
+
+  /**
+   * @brief returns the current graphicsview view as a pixmap.
+   * @return qpixmap
+   */
+  QPixmap pixmap() { return grab(); }
+
+  /**
+   * @brief returns the current graphicsview view as qimage.
+   * @return qimage
+   */
+  QImage  image();
+
+  /**
+   * @brief returns the current multiplier
+   * @return double
+   */
+  double multiplier() const { return m_multiplier; }
+
+  /**
+   * @brief returns the current max zoom value
+   * @return double
+   */
+  double maxZoom() const { return m_maxScale; }
+
+private:
+  QGraphicsScene      *m_scene = nullptr;
+  QGraphicsPixmapItem *m_pixmapItem = nullptr;
+
+  double m_currentZoom;
+  double m_minScale;
+  double m_maxScale;
+  double m_stepScale;
+  double m_multiplier;
+
+  void calculateScaleStep();
+
+protected:
+  void wheelEvent(QWheelEvent *event) override;
+  void mousePressEvent(QMouseEvent *event) override;
+  void mouseReleaseEvent(QMouseEvent *event) override;
+
+};
+
+} // namespace LtsWidgets