Dragging to resize a JavaFX Region

Here is another handy JavaFX utility to allow you to drag the bottom edge of a JavaFX Region to resize it. Layout containers inherit from Region although controls do not even though they both have a minHeight property so Controls cannot be resized using this class :(

	import javafx.event.EventHandler;
	import javafx.scene.Cursor;
	import javafx.scene.input.MouseEvent;
	import javafx.scene.layout.Region;
	/**
	* {@link DragResizer} can be used to add mouse listeners to a {@link Region}
	* and make it resizable by the user by clicking and dragging the border in the
	* same way as a window.
	* <p>
	* Only height resizing is currently implemented. Usage: <pre>DragResizer.makeResizable(myAnchorPane);</pre>
	*
	* @author atill
	*
	*/
	public class DragResizer {
	/**
	* The margin around the control that a user can click in to start resizing
	* the region.
	*/
	private static final int RESIZE_MARGIN = 5;
	private final Region region;
	private double y;
	private boolean initMinHeight;
	private boolean dragging;
	private DragResizer(Region aRegion) {
	region = aRegion;
	}
	public static void makeResizable(Region region) {
	final DragResizer resizer = new DragResizer(region);
	region.setOnMousePressed(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent event) {
	resizer.mousePressed(event);
	}});
	region.setOnMouseDragged(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent event) {
	resizer.mouseDragged(event);
	}});
	region.setOnMouseMoved(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent event) {
	resizer.mouseOver(event);
	}});
	region.setOnMouseReleased(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent event) {
	resizer.mouseReleased(event);
	}});
	}
	protected void mouseReleased(MouseEvent event) {
	dragging = false;
	region.setCursor(Cursor.DEFAULT);
	}
	protected void mouseOver(MouseEvent event) {
	if(isInDraggableZone(event) || dragging) {
	region.setCursor(Cursor.S_RESIZE);
	}
	else {
	region.setCursor(Cursor.DEFAULT);
	}
	}
	protected boolean isInDraggableZone(MouseEvent event) {
	return event.getY() > (region.getHeight() - RESIZE_MARGIN);
	}
	protected void mouseDragged(MouseEvent event) {
	if(!dragging) {
	return;
	}
	double mousey = event.getY();
	double newHeight = region.getMinHeight() + (mousey - y);
	region.setMinHeight(newHeight);
	y = mousey;
	}
	protected void mousePressed(MouseEvent event) {
	// ignore clicks outside of the draggable margin
	if(!isInDraggableZone(event)) {
	return;
	}
	dragging = true;
	// make sure that the minimum height is set to the current height once,
	// setting a min height that is smaller than the current height will
	// have no effect
	if (!initMinHeight) {
	region.setMinHeight(region.getHeight());
	initMinHeight = true;
	}
	y = event.getY();
	}
	}

view raw DragResizer.java hosted with ❤ by GitHub