How to use

getCenter

method

in

org.jxmapviewer.JXMapViewer

/**
 * Returns the bounds of the viewport in pixels. This can be used to transform points into the world bitmap
 * coordinate space.
 * @return the bounds in <em>pixels</em> of the "view" of this map
 */
public Rectangle getViewportBounds()
{
  return calculateViewportBounds(getCenter());
}

Point2D old = this.getCenter();

/**
 * Returns the bounds of the viewport in pixels. This can be used to transform points into the world bitmap
 * coordinate space.
 * @return the bounds in <em>pixels</em> of the "view" of this map
 */
public Rectangle getViewportBounds()
{
  return calculateViewportBounds(getCenter());
}

Point2D old = this.getCenter();

/**
 * A property indicating the center position of the map
 * @return the current center position
 */
public GeoPosition getCenterPosition()
{
  return getTileFactory().pixelToGeo(getCenter(), zoomLevel);
}

/**
 * A property indicating the center position of the map
 * @return the current center position
 */
public GeoPosition getCenterPosition()
{
  return getTileFactory().pixelToGeo(getCenter(), zoomLevel);
}

  @Override
  public void mouseWheelMoved(MouseWheelEvent evt)
  {
    Point current = evt.getPoint();
    Rectangle bound = viewer.getViewportBounds();
    
    double dx = current.x - bound.width / 2;
    double dy = current.y - bound.height / 2;
    
    Dimension oldMapSize = viewer.getTileFactory().getMapSize(viewer.getZoom());

    viewer.setZoom(viewer.getZoom() + evt.getWheelRotation());
    
    Dimension mapSize = viewer.getTileFactory().getMapSize(viewer.getZoom());

    Point2D center = viewer.getCenter();

    double dzw = (mapSize.getWidth() / oldMapSize.getWidth());
    double dzh = (mapSize.getHeight() / oldMapSize.getHeight());

    double x = center.getX() + dx * (dzw - 1);
    double y = center.getY() + dy * (dzh - 1);

    viewer.setCenter(new Point2D.Double(x, y));
  }
}

  @Override
  public void mouseWheelMoved(MouseWheelEvent evt)
  {
    Point current = evt.getPoint();
    Rectangle bound = viewer.getViewportBounds();
    
    double dx = current.x - bound.width / 2;
    double dy = current.y - bound.height / 2;
    
    Dimension oldMapSize = viewer.getTileFactory().getMapSize(viewer.getZoom());

    viewer.setZoom(viewer.getZoom() + evt.getWheelRotation());
    
    Dimension mapSize = viewer.getTileFactory().getMapSize(viewer.getZoom());

    Point2D center = viewer.getCenter();

    double dzw = (mapSize.getWidth() / oldMapSize.getWidth());
    double dzh = (mapSize.getHeight() / oldMapSize.getHeight());

    double x = center.getX() + dx * (dzw - 1);
    double y = center.getY() + dy * (dzh - 1);

    viewer.setCenter(new Point2D.Double(x, y));
  }
}

@Override
public void mouseDragged(MouseEvent evt)
{
  if (!SwingUtilities.isLeftMouseButton(evt))
    return;
  if (!viewer.isPanningEnabled())
    return;
  
  Point current = evt.getPoint();
  double x = viewer.getCenter().getX();
  double y = viewer.getCenter().getY();
  if(prev != null){
      x += prev.x - current.x;
      y += prev.y - current.y;
  }
  int maxHeight = (int) (viewer.getTileFactory().getMapSize(viewer.getZoom()).getHeight() * viewer
      .getTileFactory().getTileSize(viewer.getZoom()));
  if (y > maxHeight)
  {
    y = maxHeight;
  }
  prev = current;
  viewer.setCenter(new Point2D.Double(x, y));
  viewer.repaint();
}

@Override
public void mouseDragged(MouseEvent evt)
{
  if (!SwingUtilities.isLeftMouseButton(evt))
    return;
  if (!viewer.isPanningEnabled())
    return;
  
  Point current = evt.getPoint();
  double x = viewer.getCenter().getX();
  double y = viewer.getCenter().getY();
  if(prev != null){
      x += prev.x - current.x;
      y += prev.y - current.y;
  }
  int maxHeight = (int) (viewer.getTileFactory().getMapSize(viewer.getZoom()).getHeight() * viewer
      .getTileFactory().getTileSize(viewer.getZoom()));
  if (y > maxHeight)
  {
    y = maxHeight;
  }
  prev = current;
  viewer.setCenter(new Point2D.Double(x, y));
  viewer.repaint();
}

/**
 * Set the current zoom level
 * @param zoom the new zoom level
 */
public void setZoom(int zoom)
{
  if (zoom == this.zoomLevel)
  {
    return;
  }
  TileFactoryInfo info = getTileFactory().getInfo();
  // don't repaint if we are out of the valid zoom levels
  if (info != null && (zoom < info.getMinimumZoomLevel() || zoom > info.getMaximumZoomLevel()))
  {
    return;
  }
  // if(zoom >= 0 && zoom <= 15 && zoom != this.zoom) {
  int oldzoom = this.zoomLevel;
  Point2D oldCenter = getCenter();
  Dimension oldMapSize = getTileFactory().getMapSize(oldzoom);
  this.zoomLevel = zoom;
  this.firePropertyChange("zoom", oldzoom, zoom);
  Dimension mapSize = getTileFactory().getMapSize(zoom);
  setCenter(new Point2D.Double(oldCenter.getX() * (mapSize.getWidth() / oldMapSize.getWidth()), oldCenter.getY()
      * (mapSize.getHeight() / oldMapSize.getHeight())));
  repaint();
}

/**
 * Set the current zoom level
 * @param zoom the new zoom level
 */
public void setZoom(int zoom)
{
  if (zoom == this.zoomLevel)
  {
    return;
  }
  TileFactoryInfo info = getTileFactory().getInfo();
  // don't repaint if we are out of the valid zoom levels
  if (info != null && (zoom < info.getMinimumZoomLevel() || zoom > info.getMaximumZoomLevel()))
  {
    return;
  }
  // if(zoom >= 0 && zoom <= 15 && zoom != this.zoom) {
  int oldzoom = this.zoomLevel;
  Point2D oldCenter = getCenter();
  Dimension oldMapSize = getTileFactory().getMapSize(oldzoom);
  this.zoomLevel = zoom;
  this.firePropertyChange("zoom", oldzoom, zoom);
  Dimension mapSize = getTileFactory().getMapSize(zoom);
  setCenter(new Point2D.Double(oldCenter.getX() * (mapSize.getWidth() / oldMapSize.getWidth()), oldCenter.getY()
      * (mapSize.getHeight() / oldMapSize.getHeight())));
  repaint();
}