void QgsComposerView::wheelZoom( QWheelEvent * event )
{
//get mouse wheel zoom behaviour settings
QSettings mySettings;
int wheelAction = mySettings.value( "/qgis/wheel_action", 2 ).toInt();
double zoomFactor = mySettings.value( "/qgis/zoom_factor", 2 ).toDouble();
if (( QgsMapCanvas::WheelAction )wheelAction == QgsMapCanvas::WheelNothing )
{
return;
}
if ( event->modifiers() & Qt::ControlModifier )
{
//holding ctrl while wheel zooming results in a finer zoom
zoomFactor = 1.0 + ( zoomFactor - 1.0 ) / 10.0;
}
//caculate zoom scale factor
bool zoomIn = event->delta() > 0;
double scaleFactor = ( zoomIn ? 1 / zoomFactor : zoomFactor );
//get current visible part of scene
QRect viewportRect( 0, 0, viewport()->width(), viewport()->height() );
QgsRectangle visibleRect = QgsRectangle( mapToScene( viewportRect ).boundingRect() );
//transform the mouse pos to scene coordinates
QPointF scenePoint = mapToScene( event->pos() );
//adjust view center according to wheel action setting
switch (( QgsMapCanvas::WheelAction )wheelAction )
{
case QgsMapCanvas::WheelZoomAndRecenter:
{
centerOn( scenePoint.x(), scenePoint.y() );
break;
}
case QgsMapCanvas::WheelZoomToMouseCursor:
{
QgsPoint oldCenter( visibleRect.center() );
QgsPoint newCenter( scenePoint.x() + (( oldCenter.x() - scenePoint.x() ) * scaleFactor ),
scenePoint.y() + (( oldCenter.y() - scenePoint.y() ) * scaleFactor ) );
centerOn( newCenter.x(), newCenter.y() );
break;
}
default:
break;
}
//zoom composition
if ( zoomIn )
{
scale( zoomFactor, zoomFactor );
}
else
{
scale( 1 / zoomFactor, 1 / zoomFactor );
}
//update composition for new zoom
emit zoomLevelChanged();
updateRulers();
update();
//redraw cached map items
QList<QGraphicsItem *> itemList = composition()->items();
QList<QGraphicsItem *>::iterator itemIt = itemList.begin();
for ( ; itemIt != itemList.end(); ++itemIt )
{
QgsComposerMap* mypItem = dynamic_cast<QgsComposerMap *>( *itemIt );
if (( mypItem ) && ( mypItem->previewMode() == QgsComposerMap::Render ) )
{
mypItem->updateCachedImage();
}
}
}
void QgsComposerView::wheelZoom( QWheelEvent * event )
{
//get mouse wheel zoom behaviour settings
QSettings mySettings;
int wheelAction = mySettings.value( "/qgis/wheel_action", 2 ).toInt();
double zoomFactor = mySettings.value( "/qgis/zoom_factor", 2 ).toDouble();
//caculate zoom scale factor
bool zoomIn = event->delta() > 0;
double scaleFactor = ( zoomIn ? 1 / zoomFactor : zoomFactor );
//get current visible part of scene
QRect viewportRect( 0, 0, viewport()->width(), viewport()->height() );
QgsRectangle visibleRect = QgsRectangle( mapToScene( viewportRect ).boundingRect() );
//transform the mouse pos to scene coordinates
QPointF scenePoint = mapToScene( event->pos() );
//zoom composition, respecting wheel action setting
switch (( QgsMapCanvas::WheelAction )wheelAction )
{
case QgsMapCanvas::WheelZoom:
// zoom without changing extent
if ( zoomIn )
{
scale( zoomFactor, zoomFactor );
}
else
{
scale( 1 / zoomFactor, 1 / zoomFactor );
}
break;
case QgsMapCanvas::WheelZoomAndRecenter:
{
visibleRect.scale( scaleFactor, scenePoint.x(), scenePoint.y() );
fitInView( visibleRect.toRectF(), Qt::KeepAspectRatio );
break;
}
case QgsMapCanvas::WheelZoomToMouseCursor:
{
QgsPoint oldCenter( visibleRect.center() );
QgsPoint newCenter( scenePoint.x() + (( oldCenter.x() - scenePoint.x() ) * scaleFactor ),
scenePoint.y() + (( oldCenter.y() - scenePoint.y() ) * scaleFactor ) );
visibleRect.scale( scaleFactor, newCenter.x(), newCenter.y() );
fitInView( visibleRect.toRectF(), Qt::KeepAspectRatio );
break;
}
case QgsMapCanvas::WheelNothing:
return;
}
//update composition for new zoom
updateRulers();
update();
//redraw cached map items
QList<QGraphicsItem *> itemList = composition()->items();
QList<QGraphicsItem *>::iterator itemIt = itemList.begin();
for ( ; itemIt != itemList.end(); ++itemIt )
{
QgsComposerMap* mypItem = dynamic_cast<QgsComposerMap *>( *itemIt );
if (( mypItem ) && ( mypItem->previewMode() == QgsComposerMap::Render ) )
{
mypItem->updateCachedImage();
}
}
}
