Fixed: #1301 Smooth Panning and Zooming.

--HG--
branch : gsoc2011-worldeditorqt

code/nel/tools/3d/object_viewer_qt/src/plugins/landscape_editor/landscape_editor_window.cpp

@@ -267,8 +267,8 @@ int LandscapeEditorWindow::createLandscape(const QString &fileName)
 		return -1;
 	}
 	ZoneRegionObject *zoneRegion = m_zoneBuilder->zoneRegion(id);
-	m_ui.graphicsView->centerOn(zoneRegion->ligoZoneRegion().getMinX() * m_landscapeScene->cellSize(),
-								abs(zoneRegion->ligoZoneRegion().getMinY()) * m_landscapeScene->cellSize());
+	m_ui.graphicsView->setCenter(QPointF(zoneRegion->ligoZoneRegion().getMinX() * m_landscapeScene->cellSize(),
+										 abs(zoneRegion->ligoZoneRegion().getMinY()) * m_landscapeScene->cellSize()));
 
 	QListWidgetItem *item;
 	if (fileName.isEmpty())

code/nel/tools/3d/object_viewer_qt/src/plugins/landscape_editor/landscape_view.cpp

@@ -33,8 +33,7 @@ namespace LandscapeEditor
 LandscapeView::LandscapeView(QWidget *parent)
 	: QGraphicsView(parent),
 	  m_visibleGrid(true),
-	  m_visibleText(true),
-	  m_moveMouse(false)
+	  m_visibleText(false)
 {
 	//setDragMode(ScrollHandDrag);
 	setTransformationAnchor(AnchorUnderMouse);
@@ -45,6 +44,9 @@ LandscapeView::LandscapeView(QWidget *parent)
 	m_cellSize = 160;
 	m_numSteps = 0;
 	m_maxSteps = 20;
+
+	//A modified version of centerOn(), handles special cases
+	setCenter(QPointF(500.0, 500.0));
 }
 
 LandscapeView::~LandscapeView()
@@ -70,7 +72,7 @@ void LandscapeView::setVisibleText(bool visible)
 
 void LandscapeView::wheelEvent(QWheelEvent *event)
 {
-	double numDegrees = event->delta() / 8.0;
+	/*	double numDegrees = event->delta() / 8.0;
 		double numSteps = numDegrees / 15.0;
 		double factor = std::pow(1.125, numSteps);
 		if (factor > 1.0)
@@ -88,7 +90,36 @@ void LandscapeView::wheelEvent(QWheelEvent *event)
 			--m_numSteps;
 		}
 		scale(factor, factor);
-	QGraphicsView::wheelEvent(event);
+		QGraphicsView::wheelEvent(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);
 }
 
 void LandscapeView::mousePressEvent(QMouseEvent *event)
@@ -96,24 +127,108 @@ void LandscapeView::mousePressEvent(QMouseEvent *event)
 	QGraphicsView::mousePressEvent(event);
 	if (event->button() != Qt::MiddleButton)
 		return;
-	m_moveMouse = true;
-	QApplication::setOverrideCursor(Qt::ClosedHandCursor);
+
+	//For panning the view
+	m_lastPanPoint = event->pos();
+	setCursor(Qt::ClosedHandCursor);
 }
 
 void LandscapeView::mouseMoveEvent(QMouseEvent *event)
 {
-	if (m_moveMouse)
-		translate(0.001, 0.001);
+	if(!m_lastPanPoint.isNull())
+	{
+		//Get how much we panned
+		QPointF delta = mapToScene(m_lastPanPoint) - mapToScene(event->pos());
+		m_lastPanPoint = event->pos();
+
+		//Update the center ie. do the pan
+		setCenter(getCenter() + delta);
+	}
+
 	QGraphicsView::mouseMoveEvent(event);
 }
 
 void LandscapeView::mouseReleaseEvent(QMouseEvent *event)
 {
+	m_lastPanPoint = QPoint();
 	QApplication::restoreOverrideCursor();
-	m_moveMouse = false;
 	QGraphicsView::mouseReleaseEvent(event);
 }
 
+void LandscapeView::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);
+}
+
+void LandscapeView::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
+		m_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
+			m_currentCenterPoint = sceneBounds.center();
+		}
+		else
+		{
+			m_currentCenterPoint = centerPoint;
+
+			//We need to clamp the center. The centerPoint is too large
+			if (centerPoint.x() > bounds.x() + bounds.width())
+			{
+				m_currentCenterPoint.setX(bounds.x() + bounds.width());
+			}
+			else if(centerPoint.x() < bounds.x())
+			{
+				m_currentCenterPoint.setX(bounds.x());
+			}
+
+			if(centerPoint.y() > bounds.y() + bounds.height())
+			{
+				m_currentCenterPoint.setY(bounds.y() + bounds.height());
+			}
+			else if(centerPoint.y() < bounds.y())
+			{
+				m_currentCenterPoint.setY(bounds.y());
+			}
+
+		}
+	}
+
+	//Update the scrollbars
+	centerOn(m_currentCenterPoint);
+}
+
+QPointF LandscapeView::getCenter() const
+{
+	return m_currentCenterPoint;
+}
+
 void LandscapeView::drawForeground(QPainter *painter, const QRectF &rect)
 {
 	QGraphicsView::drawForeground(painter, rect);

code/nel/tools/3d/object_viewer_qt/src/plugins/landscape_editor/landscape_view.h

@@ -35,6 +35,10 @@ public:
 	LandscapeView(QWidget *parent = 0);
 	virtual ~LandscapeView();
 
+	//Set the current centerpoint in the
+	void setCenter(const QPointF &centerPoint);
+	QPointF getCenter() const;
+
 	bool isVisibleGrid() const;
 
 public Q_SLOTS:
@@ -48,6 +52,7 @@ protected:
 	virtual void mouseMoveEvent(QMouseEvent *event);
 	virtual void mouseReleaseEvent(QMouseEvent *event);
 	virtual void drawForeground(QPainter *painter, const QRectF &rect);
+	virtual void resizeEvent(QResizeEvent *event);
 
 	void drawGrid(QPainter *painter, const QRectF &rect);
 	void drawZoneNames(QPainter *painter, const QRectF &rect);
@@ -56,7 +61,12 @@ private:
 	bool m_visibleGrid, m_visibleText;
 	int m_numSteps, m_maxSteps;
 	int m_cellSize;
-	bool m_moveMouse;
+
+	//Holds the current centerpoint for the view, used for panning and zooming
+	QPointF m_currentCenterPoint;
+
+	//From panning the view
+	QPoint m_lastPanPoint;
 }; /* class LandscapeView */
 
 } /* namespace LandscapeEditor */