PanController.java

/*
 * This is part of Geomajas, a GIS framework, http://www.geomajas.org/.
 *
 * Copyright 2008-2015 Geosparc nv, http://www.geosparc.com/, Belgium.
 *
 * The program is available in open source according to the GNU Affero
 * General Public License. All contributions in this program are covered
 * by the Geomajas Contributors License Agreement. For full licensing
 * details, see LICENSE.txt in the project root.
 */
package org.geomajas.gwt.client.controller;

import org.geomajas.geometry.Coordinate;
import org.geomajas.gwt.client.map.MapView.ZoomOption;
import org.geomajas.gwt.client.map.RenderSpace;
import org.geomajas.gwt.client.spatial.Bbox;
import org.geomajas.gwt.client.widget.MapWidget;

import com.google.gwt.event.dom.client.DoubleClickEvent;
import com.google.gwt.event.dom.client.HumanInputEvent;
import com.google.gwt.event.dom.client.MouseOutEvent;
import com.smartgwt.client.types.Cursor;

/**
 * Handle panning by dragging the map. Also allows zoom to rectangle when using shift or ctrl when you start to drag.
 * Double clicking allows the user to zoom in on the clicked location.
 * 
 * @author Joachim Van der Auwera
 * @author Pieter De Graef
 */
public class PanController extends AbstractGraphicsController {

	private boolean zooming;

	private boolean panning;

	private boolean moving;

	private boolean showCursorOnMove;

	private Coordinate begin;

	private ZoomToRectangleController zoomToRectangleController;

	private Coordinate lastClickPosition;

	// Constructors:

	public PanController(MapWidget mapWidget) {
		super(mapWidget);
		zoomToRectangleController = new ZoomToRectangleController(mapWidget);
	}

	/**
	 * Should the cursor only be shown when mouse is dragged (defaults to false) ?
	 * 
	 * @return true if to be shown on drag
	 */
	public boolean isShowCursorOnMove() {
		return showCursorOnMove;
	}

	/**
	 * If set to true, the move cursor is only shown when the mouse is dragged.
	 * 
	 * @param showCursorOnMove
	 *            true if cursor should be shown on move (defaults to false)
	 */
	public void setShowCursorOnMove(boolean showCursorOnMove) {
		this.showCursorOnMove = showCursorOnMove;
	}
	
	@Override
	public void onDown(HumanInputEvent<?> event) {
		if (event.isControlKeyDown() || event.isShiftKeyDown()) {
			zooming = true;
			zoomToRectangleController.onDown(event);
		} else if (!isRightMouseButton(event)) {
			panning = true;
			mapWidget.getMapModel().getMapView().setPanDragging(true);
			begin = getLocation(event, RenderSpace.SCREEN);
			if (!isShowCursorOnMove()) {
				mapWidget.setCursor(Cursor.MOVE);
			}
		}
		lastClickPosition = getLocation(event, RenderSpace.WORLD);
	}
	
	@Override
	public void onUp(HumanInputEvent<?> event) {
		if (zooming) {
			zoomToRectangleController.onUp(event);
			zooming = false;
		} else if (panning) {
			stopPanning(event);
		}
	}

	@Override
	public void onDrag(HumanInputEvent<?> event) {
		if (zooming) {
			zoomToRectangleController.onDrag(event);
		} else if (panning) {
			if (!moving && isShowCursorOnMove()) {
				mapWidget.setCursor(Cursor.MOVE);
			}
			moving = true;
			updateView(event);
		}
	}

	@Override
	public void onMouseOut(MouseOutEvent event) {
		if (zooming) {
			zoomToRectangleController.onMouseOut(event);
		} else {
			stopPanning(null);
		}
	}

	/**
	 * Zoom in to the double-clicked position.
	 */
	public void onDoubleClick(DoubleClickEvent event) {
		//Check if there was a last click that was handled in this class.
		if (null != lastClickPosition) {
			// Zoom in on the event location.
			Bbox bounds = mapWidget.getMapModel().getMapView().getBounds();
			double x = lastClickPosition.getX() - (bounds.getWidth() / 4);
			double y = lastClickPosition.getY() - (bounds.getHeight() / 4);
			Bbox newBounds = new Bbox(x, y, bounds.getWidth() / 2, bounds.getHeight() / 2);
			mapWidget.getMapModel().getMapView().applyBounds(newBounds, ZoomOption.LEVEL_CHANGE);
		}
	}

	public boolean isMoving() {
		return moving;
	}

	// Private methods:

	private void stopPanning(HumanInputEvent<?> event) {
		mapWidget.getMapModel().getMapView().setPanDragging(false);
		panning = false;
		moving = false;
		mapWidget.setCursorString(mapWidget.getDefaultCursorString());
		if (null != event) {
			updateView(event);
		}
	}

	private void updateView(HumanInputEvent<?> event) {
		Coordinate end = getLocation(event, RenderSpace.SCREEN);
		Coordinate beginWorld = getTransformer().viewToWorld(begin);
		Coordinate endWorld = getTransformer().viewToWorld(end);
		mapWidget.getMapModel().getMapView()
				.translate(beginWorld.getX() - endWorld.getX(), beginWorld.getY() - endWorld.getY());
		begin = end;
	}

	@Override
	public void onDeactivate() {
		super.onDeactivate();
		zoomToRectangleController.onDeactivate();
	}
}