Java SE (Java Platform, Standard Edition)

Hello, this is my first post.


I'd like to add zoom in/out function to my ScrollPane, and make shortcut (CTRL+MOUSE SCROLL UP/DOWN) for it. ( like Inkscape )

I made the following code ( Canvas ) to achieve this, but have some problems.

*1. How can I prevent ScrollBar's thumb to move when pressing CTRL?*
When ScrollBar is visible and ScrollBar's thumb (or scroller, knob) has room to move, CTRL+MOUSE SCROLL UP/DOWN doesn't work because the thumb moves instead of zooming in/out.
When the thumb moves up/down to bar's end, then zoom in/out finally works fine.

*2. ScrollEvent handler is sometimes not called in ScrollPane*
When ScrollBarPolicy is not ScrollBarPolicy.ALWAYS and Scrollbar is not visible, SOMETIMES CTRL+SCROLL UP/DOWN operation dosen't work.
(ScrollEvent handler is not called. For other panes, ScrollEvent works fine. Please check MouseScrollEventTest below)

Thank you in advance.


Canvas

public class Canvas extends Application {
	DoubleProperty zoom = new SimpleDoubleProperty(1.0);
	final double MAX_ZOOM = 3.0;
	final double MIN_ZOOM = 0.1;
	
	@Override
	public void start(Stage stage) throws Exception {
		Rectangle rectangle = RectangleBuilder.create()
			.width(1000).height(1000)
			.fill( LinearGradientBuilder.create()
				.stops(new Stop(0, Color.BLUE), new Stop(1, Color.RED))
				.build()
			).build();
		
		ScrollPane scrollPane = ScrollPaneBuilder.create()
			.content(
				GroupBuilder.create()
					.children(rectangle)
					.build())
//			.hbarPolicy(ScrollBarPolicy.ALWAYS)
//			.vbarPolicy(ScrollBarPolicy.ALWAYS)
			.build();
		
		rectangle.scaleXProperty().bind(zoom);
		rectangle.scaleYProperty().bind(zoom);
		
		scrollPane.setOnScroll(new EventHandler<ScrollEvent>(){
			public void handle(ScrollEvent event) {
				if( !event.isControlDown() ) return ;
				
				double zoomValue;
				if ( event.getDeltaY() > 0 ) {
					zoomValue = zoom.get() + 0.1;
				} else {
					zoomValue = zoom.get() - 0.1;
				}
				
				if( zoomValue > MAX_ZOOM || zoomValue < MIN_ZOOM ) return ;
				
				zoom.set(zoomValue);
			}
		});
		
		Scene scene = SceneBuilder.create()
				.width(500).height(500)
				.root(scrollPane)
				.build();
		
		stage.setScene(scene);
		stage.show();
	}
	
	
	public static void main(String[] args) {
		launch(args);
	}
}

Mouse Scroll Event Test

public class MouseScrollEventTest extends Application {
	BorderPane bPane;
	ScrollPane sPane;

	public void start(Stage stage) throws Exception {
		EventHandler<ScrollEvent> handler = new EventHandler<ScrollEvent>() {
			public void handle(ScrollEvent event) {
				System.out.println(event);
			}
		};
		
		bPane = new BorderPane();
		bPane.setPrefSize(100, 100);
		
		sPane = new ScrollPane();
		sPane.setPrefSize(100, 100);
//		sPane.setContent( new Rectangle(50,50) );
		
//             This works fine.
		bPane.setOnScroll(handler);
//             Sometimes, this is not called.
		sPane.setOnScroll(handler);
		
		HBox root = new HBox();
		root.getChildren().addAll(bPane, sPane);
		
		Scene scene = new Scene(root);
//		scene.setOnScroll(handler);
		
		stage.setScene(scene);
		stage.show();
	}
	
	public static void main(String[] args) {
		launch(args);
	}	
}

--- My Environment
Windows Vista
JavaFX 2.0 SDK
---

Edited by: 932474 on 2012/05/07 4:31

Edited by: 932474 on 2012/05/07 4:47