Ejemplo n.º 1
0
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();
    }
  }
}
Ejemplo n.º 2
0
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();
    }
  }
}