package jcgp.gui.dragresize; import javafx.event.EventHandler; import javafx.scene.Cursor; import javafx.scene.input.MouseEvent; import javafx.scene.layout.Region; import jcgp.gui.constants.Constants; /** * This class adds horizontal drag resize functionality to any * arbitrary region provided. This is done by using the static * method {@code makeDragResizable()}. *

* This is based on a class by Andrew Till found on: * http://andrewtill.blogspot.co.uk/2012/12/dragging-to-resize-javafx-region.html * */ public class HorizontalDragResize { private boolean dragging = false; private final Region region; /** * For internal use only, creates an instance of the actual * resizer used. * * @param region the region to make resizable. */ private HorizontalDragResize(Region region) { this.region = region; } /** * Makes the specified region drag resizable. * This particular implementation only creates a resize * click-and-drag area on the left side of the region. * The resize area is defined by {@code GUI.RESIZE_MARGIN}. * * @param region the region to make resizable. */ public static void makeDragResizable(final Region region) { // make the instance, this actually performs the resizing final HorizontalDragResize dr = new HorizontalDragResize(region); // set mouse listeners region.setOnMousePressed(new EventHandler() { @Override public void handle(MouseEvent event) { dr.mousePressed(event); } }); region.setOnMouseDragged(new EventHandler() { @Override public void handle(MouseEvent event) { dr.mouseDragged(event); } }); region.setOnMouseMoved(new EventHandler() { @Override public void handle(MouseEvent event) { dr.mouseMoved(event); } }); region.setOnMouseReleased(new EventHandler() { @Override public void handle(MouseEvent event) { dr.mouseReleased(); } }); } /** * If the press happened in the resize area, raise the drag flag. * * @param event the associated mouse event. */ private void mousePressed(MouseEvent event) { if(isInDraggableZone(event)) { dragging = true; } } /** * If drag flag is high, resize the region to match the mouse position. * * @param event the associated mouse event. */ private void mouseDragged(MouseEvent event) { if(dragging) { double newWidth = region.getWidth() - event.getX(); if (newWidth >= region.getMinWidth()) { region.setPrefWidth(newWidth); } else { region.setPrefWidth(region.getMinWidth()); } } } /** * Change the cursor if the mouse position overlaps with the resize area. * * @param event the associated mouse event. */ private void mouseMoved(MouseEvent event) { if(isInDraggableZone(event) || dragging) { region.setCursor(Cursor.H_RESIZE); } else { region.setCursor(Cursor.DEFAULT); } } /** * Finish resizing. */ private void mouseReleased() { dragging = false; region.setCursor(Cursor.DEFAULT); } /** * Assert whether the mouse cursor is in the draggable area defined by {@code GUI.RESIZE_MARGIN}. * * @param event the associated mouse event. * @return true if the mouse position is in the draggable area. */ private boolean isInDraggableZone(MouseEvent event) { return event.getX() < (Constants.RESIZE_MARGIN); } }