This class acts as a single handle for the PdfCropping class. More...

#include <PdfFrameHandle.h>

Inheritance diagram for PdfFrameHandle:

Collaboration diagram for PdfFrameHandle:

Public Member Functions
	PdfFrameHandle (QGraphicsScene &scene, QGraphicsView &view, const QPointF &pointReference, int orientationFlags, PdfCropping &pdfCropping, int zValue)
	Single constructor. More...

virtual QVariant	itemChange (GraphicsItemChange change, const QVariant &value)
	Intercept the drags and process them, which is the whole point of handles. More...

virtual void	paint (QPainter painter, const QStyleOptionGraphicsItem option, QWidget *widget)
	Override the paint method so the dashed-border-when-selected can be removed. More...

void	setDisableEventsWhileMovingAutomatically (bool disable)
	Temporarily disable event handling so code can move this object without triggering a cascade of events. More...

Detailed Description

This class acts as a single handle for the PdfCropping class.

Definition at line 18 of file PdfFrameHandle.h.

Constructor & Destructor Documentation

◆ PdfFrameHandle()

PdfFrameHandle::PdfFrameHandle	(	QGraphicsScene &	scene,
		QGraphicsView &	view,
		const QPointF &	pointReference,
		int	orientationFlags,
		PdfCropping &	pdfCropping,
		int	zValue
	)

Single constructor.

Definition at line 16 of file PdfFrameHandle.cpp.

                                             :
   m_pdfCropping (pdfCropping),
   m_orientationFlags (orientationFlags),
   m_disableEventsWhileMovingAutomatically (false),
   m_scene (scene),
   m_view (view)
 {
   const double SUBTLE_OPACITY = 0.2;
  
   // Advantages of using ItemIgnoresTransformations:
   //   1) handles do not get bigger or smaller depending on the size of the image
   //   2) handles never get ugly when zoomed in
   //   3) handles never get too tiny when zoomed out
   // Disadvantages of using ItemIgnoresTransformation:
   //   1) Resizing the preview window with ItemIgnoresTransformations moves the handles out of position
   //   2) More conversions back and forth between untransformed and transformed coordinates. This was the deal breaker since
   //      the transformations were undocumented and ultimately too difficult
   // The solution is to have constant-size handles WITHOUT ItemIgnoresTransformations. This means resizing the window
   // also involves resizing the handles, but everything else is pretty easy
   //
   // ItemIgnoresTransformations flag must agree with the QGraphicsRectItem used for the frame box by PdfCropping
   setFlags (QGraphicsItem::ItemIsMovable |
             QGraphicsItem::ItemIsSelectable |
             QGraphicsItem::ItemSendsScenePositionChanges);
  
   // Fill with nice color for better visibility. Note that the pen is disabled by overriding the paint method
   setBrush (QBrush (Qt::blue));
   setVisible (true);
   setZValue (zValue);
   setOpacity (SUBTLE_OPACITY);
   setPos (pointReference); // Point position is handled in scene/view coordinates
  
   // Add to scene
   scene.addItem (this);
  
   QSize handleSize = m_pdfCropping.windowSize() / HANDLE_SIZE_AS_FRACTION_OF_WINDOW_SIZE;
  
   // Adjust positions of handles that are not at the top left so handles are laid out symmetrically
   QPointF pointPos = pointReference;
   if ((orientationFlags & PdfCropping::PDF_CROPPING_LEFT) != 0) {
     pointPos.setX (pointPos.x() - handleSize.width() / 2.0);
   } else if ((orientationFlags & PdfCropping::PDF_CROPPING_RIGHT) != 0) {
     pointPos.setX (pointPos.x() + handleSize.width() / 2.0);
   }
   if ((orientationFlags & PdfCropping::PDF_CROPPING_TOP) != 0) {
     pointPos.setY (pointPos.y() - handleSize.height() / 2.0);
   } else if ((orientationFlags & PdfCropping::PDF_CROPPING_BOTTOM) != 0) {
     pointPos.setY (pointPos.y() + handleSize.height() / 2.0);
   }
  
   // Start with geometry. Since point positions are handled in scene/view coordinates, we have to convert
   // to local coordinates for the rectangle
   QPointF topLeftLocal = mapFromScene (pointPos);
  
   setRect (QRectF (topLeftLocal,
                    handleSize));

Member Function Documentation

◆ itemChange()

QVariant PdfFrameHandle::itemChange	(	GraphicsItemChange	change,
		const QVariant &	value
	)

virtual

Intercept the drags and process them, which is the whole point of handles.

Definition at line 79 of file PdfFrameHandle.cpp.

 {
   QVariant valueFiltered = value;
  
   if (change == ItemPositionChange && scene()) {
  
     QPointF sizeAsPointF (boundingRect().size().width(),
                           boundingRect().size().height());
  
     // New position is in the value argument
     QPointF newPos = valueFiltered.toPointF();
     QPointF oldPos = pos ();
  
     // This sequence is from http://www.qtcentre.org/threads/47248-How-to-efficiently-get-position-of-a-QGraphicsItem-in-view-coordinates
     QRectF newRectItem (newPos,
                         QSize (qFloor (boundingRect().size().width()),
                                qFloor (boundingRect().size().height())));
     QPolygonF newRectScene = mapToScene (newRectItem);
     QPolygon newRectView = m_view.mapFromScene (newRectScene.boundingRect());
  
     // Skip moving of this handle if it will go outside of the window
     QRectF rectWindow = m_scene.sceneRect();
     if (!rectWindow.contains (newRectView.boundingRect())) {
  
       // Keep the item inside the scene rectangle
       newPos.setX (qMin (rectWindow.right(), qMax (newPos.x(), rectWindow.left())));
       newPos.setY (qMin (rectWindow.bottom(), qMax (newPos.y(), rectWindow.top())));
  
       valueFiltered = (newPos);
  
     }
  
     // Skip moving of other handles, in response to the move of this handle, if event handling is (temporarily) off,
     // to prevent an infinite loop
     if (!m_disableEventsWhileMovingAutomatically) {
  
       bool left   = ((m_orientationFlags & PdfCropping::PDF_CROPPING_LEFT  ) != 0);
       bool right  = ((m_orientationFlags & PdfCropping::PDF_CROPPING_RIGHT ) != 0);
       bool top    = ((m_orientationFlags & PdfCropping::PDF_CROPPING_TOP   ) != 0);
       bool bottom = ((m_orientationFlags & PdfCropping::PDF_CROPPING_BOTTOM) != 0);
  
       if (left && top) {
         m_pdfCropping.moveTL (newPos, oldPos);
       } else if (right && top) {
         m_pdfCropping.moveTR (newPos, oldPos);
       } else if (right && bottom) {
         m_pdfCropping.moveBR (newPos, oldPos);
       } else if (left && bottom) {
         m_pdfCropping.moveBL (newPos, oldPos);
       }
     }
   }
  
   return QGraphicsItem::itemChange(change, valueFiltered);

◆ paint()

void PdfFrameHandle::paint	(	QPainter *	painter,
		const QStyleOptionGraphicsItem *	option,
		QWidget *	widget
	)

virtual

Override the paint method so the dashed-border-when-selected can be removed.

Definition at line 136 of file PdfFrameHandle.cpp.

 {
   // Temporarily remove the selected option
   QStyleOptionGraphicsItem scrubbed (*option);
   scrubbed.state &= ~QStyle::State_Selected;
   QGraphicsRectItem::paint (painter, &scrubbed, widget);

◆ setDisableEventsWhileMovingAutomatically()

void PdfFrameHandle::setDisableEventsWhileMovingAutomatically ( bool disable )

Temporarily disable event handling so code can move this object without triggering a cascade of events.

Definition at line 144 of file PdfFrameHandle.cpp.

146 {

147 m_disableEventsWhileMovingAutomatically = disable;

The documentation for this class was generated from the following files:

Pdf/PdfFrameHandle.h
Pdf/PdfFrameHandle.cpp