Zum Zoomen innerhalb eines ScrollPane
müssen Sie die Bildlaufpositionen anpassen. Dies ist ein bisschen komplexer als nur eine Transformation anhängen, was getan werden könnte, wenn keine ScrollPane
verwendet wurde.
Grundsätzlich müssen Sie vor dem Skalieren des Knotens die aktuelle Bildlaufposition prüfen und nach dem Skalieren die Bildlaufpositionen ändern, um zu verhindern, dass der Pivotpunkt aufgrund des geänderten Skalierungsfaktors seine Position ändert.
Im folgenden Beispiel können Sie einen Kreis in einem Raster bewegen und sich um das Raster bewegen, wenn Sie nicht auf einen Kreis klicken (pannable ScrollPane
). Außerdem können Sie den Zoom anpassen, wenn Sie das Mausrad gedrückt halten der CTRL Schlüssel.
import java.net.MalformedURLException;
import javafx.application.Application;
import javafx.geometry.Bounds;
import javafx.geometry.Point2D;
import javafx.geometry.Pos;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.SplitPane;
import javafx.scene.layout.Pane;
import javafx.scene.layout.Region;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
public class PivotZoom extends Application {
public static Region createContent() {
double width = 1000;
double height = 1000;
Canvas canvas = new Canvas(width, height);
GraphicsContext gc = canvas.getGraphicsContext2D();
gc.setFill(Color.LIGHTGREY);
gc.fillRect(0, 0, width, height);
gc.setStroke(Color.BLUE);
gc.beginPath();
for (int i = 50; i < width; i += 50) {
gc.moveTo(i, 0);
gc.lineTo(i, height);
}
for (int i = 50; i < height; i += 50) {
gc.moveTo(0, i);
gc.lineTo(width, i);
}
gc.stroke();
Pane content = new Pane(
new Circle(50, 50, 20),
new Circle(120, 90, 20, Color.RED),
new Circle(200, 70, 20, Color.GREEN)
);
StackPane result = new StackPane(canvas, content);
result.setAlignment(Pos.TOP_LEFT);
class DragData {
double startX;
double startY;
double startLayoutX;
double startLayoutY;
Node dragTarget;
}
DragData dragData = new DragData();
content.setOnMousePressed(evt -> {
if (evt.getTarget() != content) {
// initiate drag gesture, if a child of content receives the
// event to prevent ScrollPane from panning.
evt.consume();
evt.setDragDetect(true);
}
});
content.setOnDragDetected(evt -> {
Node n = (Node) evt.getTarget();
if (n != content) {
// set start paremeters
while (n.getParent() != content) {
n = n.getParent();
}
dragData.startX = evt.getX();
dragData.startY = evt.getY();
dragData.startLayoutX = n.getLayoutX();
dragData.startLayoutY = n.getLayoutY();
dragData.dragTarget = n;
n.startFullDrag();
evt.consume();
}
});
// stop dragging when mouse is released
content.setOnMouseReleased(evt -> dragData.dragTarget = null);
content.setOnMouseDragged(evt -> {
if (dragData.dragTarget != null) {
// move dragged node
dragData.dragTarget.setLayoutX(evt.getX() + dragData.startLayoutX - dragData.startX);
dragData.dragTarget.setLayoutY(evt.getY() + dragData.startLayoutY - dragData.startY);
Point2D p = new Point2D(evt.getX(), evt.getY());
evt.consume();
}
});
return result;
}
@Override
public void start(Stage primaryStage) throws MalformedURLException {
Region zoomTarget = createContent();
zoomTarget.setPrefSize(1000, 1000);
zoomTarget.setOnDragDetected(evt -> {
Node target = (Node) evt.getTarget();
while (target != zoomTarget && target != null) {
target = target.getParent();
}
if (target != null) {
target.startFullDrag();
}
});
Group group = new Group(zoomTarget);
// stackpane for centering the content, in case the ScrollPane viewport
// is larget than zoomTarget
StackPane content = new StackPane(group);
group.layoutBoundsProperty().addListener((observable, oldBounds, newBounds) -> {
// keep it at least as large as the content
content.setMinWidth(newBounds.getWidth());
content.setMinHeight(newBounds.getHeight());
});
ScrollPane scrollPane = new ScrollPane(content);
scrollPane.setPannable(true);
scrollPane.viewportBoundsProperty().addListener((observable, oldBounds, newBounds) -> {
// use vieport size, if not too small for zoomTarget
content.setPrefSize(newBounds.getWidth(), newBounds.getHeight());
});
content.setOnScroll(evt -> {
if (evt.isControlDown()) {
evt.consume();
final double zoomFactor = evt.getDeltaY() > 0 ? 1.2 : 1/1.2;
Bounds groupBounds = group.getLayoutBounds();
final Bounds viewportBounds = scrollPane.getViewportBounds();
// calculate pixel offsets from [0, 1] range
double valX = scrollPane.getHvalue() * (groupBounds.getWidth() - viewportBounds.getWidth());
double valY = scrollPane.getVvalue() * (groupBounds.getHeight() - viewportBounds.getHeight());
// convert content coordinates to zoomTarget coordinates
Point2D posInZoomTarget = zoomTarget.parentToLocal(group.parentToLocal(new Point2D(evt.getX(), evt.getY())));
// calculate adjustment of scroll position (pixels)
Point2D adjustment = zoomTarget.getLocalToParentTransform().deltaTransform(posInZoomTarget.multiply(zoomFactor - 1));
// do the resizing
zoomTarget.setScaleX(zoomFactor * zoomTarget.getScaleX());
zoomTarget.setScaleY(zoomFactor * zoomTarget.getScaleY());
// refresh ScrollPane scroll positions & content bounds
scrollPane.layout();
// convert back to [0, 1] range
// (too large/small values are automatically corrected by ScrollPane)
groupBounds = group.getLayoutBounds();
scrollPane.setHvalue((valX + adjustment.getX())/(groupBounds.getWidth() - viewportBounds.getWidth()));
scrollPane.setVvalue((valY + adjustment.getY())/(groupBounds.getHeight() - viewportBounds.getHeight()));
}
});
StackPane left = new StackPane(new Label("Left Menu"));
SplitPane root = new SplitPane(left, scrollPane);
Scene scene = new Scene(root, 800, 600);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
Vielen Dank. Leider brauche ich eine Kombination aus Ziehen und Zoomen. Das Ziehen fehlt noch –
@RadimBurget Hier gehts. Pannable, zoombar und enthält nun ein Raster mit ziehbaren Kreisen ... – fabian