Subversion Repositories bw_tiff_compression

/*
 * Thanks to the autor of http://www.qtcentre.org/wiki/index.php?title=QGraphicsView:_Smooth_Panning_and_Zooming
 */
 
//Our includes
#include "CMyGraphicsView.h"
#include "stddefs.h"
 
//Qt includes
#include <QGraphicsTextItem>
#include <QTextStream>
#include <QScrollBar>
#include <QMouseEvent>
#include <QWheelEvent>
#include <QDebug>
#include <QBrush>
 
/**
* Sets up the subclassed QGraphicsView
*/
CMyGraphicsView::CMyGraphicsView(QWidget* parent) : QGraphicsView(parent) {
 
	setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
 
	//Set-up the scene
	Scene = new QGraphicsScene(this);
    QBrush oBrush;
    oBrush.setColor(Qt::lightGray);
    oBrush.setStyle(Qt::SolidPattern);
    Scene->setBackgroundBrush(oBrush);
	setScene(Scene);
	setCursor(Qt::OpenHandCursor);
//    setBackgroundBrush();
}
 
/**
  * Sets the current centerpoint.  Also updates the scene's center point.
  * Unlike centerOn, which has no way of getting the floating point center
  * back, SetCenter() stores the center point.  It also handles the special
  * sidebar case.  This function will claim the centerPoint to sceneRec ie.
  * the centerPoint must be within the sceneRec.
  */
//Set the current centerpoint in the
void CMyGraphicsView::SetCenter(const QPointF& centerPoint) {
	//Get the rectangle of the visible area in scene coords
	QRectF visibleArea = mapToScene(rect()).boundingRect();
 
	//Get the scene area
	QRectF sceneBounds = sceneRect();
 
	double boundX = visibleArea.width() / 2.0;
	double boundY = visibleArea.height() / 2.0;
	double boundWidth = sceneBounds.width() - 2.0 * boundX;
	double boundHeight = sceneBounds.height() - 2.0 * boundY;
 
	//The max boundary that the centerPoint can be to
	QRectF bounds(boundX, boundY, boundWidth, boundHeight);
 
	if(bounds.contains(centerPoint)) {
		//We are within the bounds
		CurrentCenterPoint = centerPoint;
	} else {
		//We need to clamp or use the center of the screen
		if(visibleArea.contains(sceneBounds)) {
			//Use the center of scene ie. we can see the whole scene
			CurrentCenterPoint = sceneBounds.center();
		} else {
 
			CurrentCenterPoint = centerPoint;
 
			//We need to clamp the center. The centerPoint is too large
			if(centerPoint.x() > bounds.x() + bounds.width()) {
				CurrentCenterPoint.setX(bounds.x() + bounds.width());
			} else if(centerPoint.x() < bounds.x()) {
				CurrentCenterPoint.setX(bounds.x());
			}
 
			if(centerPoint.y() > bounds.y() + bounds.height()) {
				CurrentCenterPoint.setY(bounds.y() + bounds.height());
			} else if(centerPoint.y() < bounds.y()) {
				CurrentCenterPoint.setY(bounds.y());
			}
 
		}
	}
 
	//Update the scrollbars
	centerOn(CurrentCenterPoint);
}
 
/**
  * Handles when the mouse button is pressed
  */
void CMyGraphicsView::mousePressEvent(QMouseEvent* event) {
	//For panning the view
	LastPanPoint = event->pos();
	setCursor(Qt::ClosedHandCursor);
}
 
/**
  * Handles when the mouse button is released
  */
void CMyGraphicsView::mouseReleaseEvent(QMouseEvent* event)
{
	REFER(event);
	setCursor(Qt::OpenHandCursor);
	LastPanPoint = QPoint();
}
 
/**
*Handles the mouse move event
*/
void CMyGraphicsView::mouseMoveEvent(QMouseEvent* event) {
	if(!LastPanPoint.isNull()) {
		//Get how much we panned
		QPointF delta = mapToScene(LastPanPoint) - mapToScene(event->pos());
		LastPanPoint = event->pos();
 
		//Update the center ie. do the pan
		SetCenter(GetCenter() + delta);
	}
}
 
/**
  * Zoom the view in and out.
  */
void CMyGraphicsView::wheelEvent(QWheelEvent* event) {
 
	//Get the position of the mouse before scaling, in scene coords
	QPointF pointBeforeScale(mapToScene(event->pos()));
 
	//Get the original screen centerpoint
	QPointF screenCenter = GetCenter(); //CurrentCenterPoint; //(visRect.center());
 
	//Scale the view ie. do the zoom
	double scaleFactor = 1.15; //How fast we zoom
	if(event->delta() > 0) {
		//Zoom in
		scale(scaleFactor, scaleFactor);
	} else {
		//Zooming out
		scale(1.0 / scaleFactor, 1.0 / scaleFactor);
	}
 
	//Get the position after scaling, in scene coords
	QPointF pointAfterScale(mapToScene(event->pos()));
 
	//Get the offset of how the screen moved
	QPointF offset = pointBeforeScale - pointAfterScale;
 
	//Adjust to the new center for correct zooming
	QPointF newCenter = screenCenter + offset;
	SetCenter(newCenter);
}
 
/**
  * Need to update the center so there is no jolt in the
  * interaction after resizing the widget.
  */
void CMyGraphicsView::resizeEvent(QResizeEvent* event) {
	//Get the rectangle of the visible area in scene coords
	QRectF visibleArea = mapToScene(rect()).boundingRect();
	SetCenter(visibleArea.center());
 
	//Call the subclass resize so the scrollbars are updated correctly
	QGraphicsView::resizeEvent(event);
}