10
Ich versuche, eine Anwendung mit einem zoombaren/pannable Canvas zu erstellen.Skalierung am Drehpunkt in einem bereits skalierten Knoten
Eigenschaften:
- Zoom in/out mit an Drehpunkten Mausrad
- ziehen die Knoten auf der Leinwand mit der linken Maustaste um
- ziehen die gesamte Leinwand mit der rechten Maustaste
Das Zoomen am Pivot-Punkt funktioniert so lange, wie Sie das Zoomen mit Skalierung 1 starten. Positionieren Sie die Maus über einen Rasterpunkt und scrollen Sie mit t er Mausrad. Der Drehpunkt bleibt dort, wo Sie mit dem Zoomen begonnen haben.
Problem:
Wenn Sie die Ansicht vergrößern, dann mit der Maus auf einen anderen Punkt bewegen und wieder vergrößern, dann wird der Drehpunkt verschoben und Zoomen geschieht nicht mehr in der Anfangsmausposition.
Beispiel:
Hier ist der Code:
import javafx.application.Application;
import javafx.event.EventHandler;
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.input.MouseEvent;
import javafx.scene.input.ScrollEvent;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.scene.transform.Scale;
import javafx.stage.Stage;
/**
* The canvas which holds all of the nodes of the application.
*/
class PannableCanvas extends Pane {
Scale scaleTransform;
public PannableCanvas() {
setPrefSize(600, 600);
setStyle("-fx-background-color: lightgrey; -fx-border-color: blue;");
// add scale transform
scaleTransform = new Scale(1.0, 1.0);
getTransforms().add(scaleTransform);
// logging
addEventFilter(MouseEvent.MOUSE_PRESSED, event -> {
System.out.println(
"canvas event: " + (((event.getSceneX() - getBoundsInParent().getMinX())/getScale()) + ", scale: " + getScale())
);
System.out.println("canvas bounds: " + getBoundsInParent());
});
}
/**
* Add a grid to the canvas, send it to back
*/
public void addGrid() {
double w = getBoundsInLocal().getWidth();
double h = getBoundsInLocal().getHeight();
// add grid
Canvas grid = new Canvas(w, h);
// don't catch mouse events
grid.setMouseTransparent(true);
GraphicsContext gc = grid.getGraphicsContext2D();
gc.setStroke(Color.GRAY);
gc.setLineWidth(1);
// draw grid lines
double offset = 50;
for(double i=offset; i < w; i+=offset) {
// vertical
gc.strokeLine(i, 0, i, h);
// horizontal
gc.strokeLine(0, i, w, i);
}
getChildren().add(grid);
grid.toBack();
}
public Scale getScaleTransform() {
return scaleTransform;
}
public double getScale() {
return scaleTransform.getY();
}
/**
* Set x/y scale
* @param scale
*/
public void setScale(double scale) {
scaleTransform.setX(scale);
scaleTransform.setY(scale);
}
/**
* Set x/y pivot points
* @param x
* @param y
*/
public void setPivot(double x, double y) {
scaleTransform.setPivotX(x);
scaleTransform.setPivotY(y);
}
}
/**
* Mouse drag context used for scene and nodes.
*/
class DragContext {
double mouseAnchorX;
double mouseAnchorY;
double translateAnchorX;
double translateAnchorY;
}
/**
* Listeners for making the nodes draggable via left mouse button. Considers if parent is zoomed.
*/
class NodeGestures {
private DragContext nodeDragContext = new DragContext();
PannableCanvas canvas;
public NodeGestures(PannableCanvas canvas) {
this.canvas = canvas;
}
public EventHandler<MouseEvent> getOnMousePressedEventHandler() {
return onMousePressedEventHandler;
}
public EventHandler<MouseEvent> getOnMouseDraggedEventHandler() {
return onMouseDraggedEventHandler;
}
private EventHandler<MouseEvent> onMousePressedEventHandler = new EventHandler<MouseEvent>() {
public void handle(MouseEvent event) {
// left mouse button => dragging
if(!event.isPrimaryButtonDown())
return;
nodeDragContext.mouseAnchorX = event.getSceneX();
nodeDragContext.mouseAnchorY = event.getSceneY();
Node node = (Node) event.getSource();
nodeDragContext.translateAnchorX = node.getTranslateX();
nodeDragContext.translateAnchorY = node.getTranslateY();
}
};
private EventHandler<MouseEvent> onMouseDraggedEventHandler = new EventHandler<MouseEvent>() {
public void handle(MouseEvent event) {
// left mouse button => dragging
if(!event.isPrimaryButtonDown())
return;
double scale = canvas.getScale();
Node node = (Node) event.getSource();
node.setTranslateX(nodeDragContext.translateAnchorX + ((event.getSceneX() - nodeDragContext.mouseAnchorX)/scale));
node.setTranslateY(nodeDragContext.translateAnchorY + ((event.getSceneY() - nodeDragContext.mouseAnchorY)/scale));
event.consume();
}
};
}
/**
* Listeners for making the scene's canvas draggable and zoomable
*/
class SceneGestures {
private static final double MAX_SCALE = 10.0d;
private static final double MIN_SCALE = .1d;
private DragContext sceneDragContext = new DragContext();
PannableCanvas canvas;
public SceneGestures(PannableCanvas canvas) {
this.canvas = canvas;
}
public EventHandler<MouseEvent> getOnMousePressedEventHandler() {
return onMousePressedEventHandler;
}
public EventHandler<MouseEvent> getOnMouseDraggedEventHandler() {
return onMouseDraggedEventHandler;
}
public EventHandler<ScrollEvent> getOnScrollEventHandler() {
return onScrollEventHandler;
}
private EventHandler<MouseEvent> onMousePressedEventHandler = new EventHandler<MouseEvent>() {
public void handle(MouseEvent event) {
// right mouse button => panning
if(!event.isSecondaryButtonDown())
return;
sceneDragContext.mouseAnchorX = event.getSceneX();
sceneDragContext.mouseAnchorY = event.getSceneY();
sceneDragContext.translateAnchorX = canvas.getTranslateX();
sceneDragContext.translateAnchorY = canvas.getTranslateY();
}
};
private EventHandler<MouseEvent> onMouseDraggedEventHandler = new EventHandler<MouseEvent>() {
public void handle(MouseEvent event) {
// right mouse button => panning
if(!event.isSecondaryButtonDown())
return;
canvas.setTranslateX(sceneDragContext.translateAnchorX + event.getSceneX() - sceneDragContext.mouseAnchorX);
canvas.setTranslateY(sceneDragContext.translateAnchorY + event.getSceneY() - sceneDragContext.mouseAnchorY);
event.consume();
}
};
/**
* Mouse wheel handler: zoom to pivot point
*/
private EventHandler<ScrollEvent> onScrollEventHandler = new EventHandler<ScrollEvent>() {
@Override
public void handle(ScrollEvent event) {
double delta = 1;
double scale = canvas.getScale(); // currently we only use Y, same value is used for X
double oldScale = scale;
if (event.getDeltaY() < 0)
scale -= delta;
else
scale += delta;
if (scale <= MIN_SCALE) {
scale = MIN_SCALE;
} else if (scale >= MAX_SCALE) {
scale = MAX_SCALE;
}
// pivot value must be untransformed, i. e. without scaling
canvas.setPivot(
((event.getSceneX() - canvas.getBoundsInParent().getMinX())/oldScale),
((event.getSceneY() - canvas.getBoundsInParent().getMinY())/oldScale)
);
canvas.setScale(scale);
System.out.println("new pivot x: " + canvas.scaleTransform.getPivotX() + "/" + canvas.scaleTransform.getPivotY() + ", new scale: " + scale);
System.out.println("bounds: " + canvas.getBoundsInParent());
event.consume();
}
};
}
/**
* An application with a zoomable and pannable canvas.
*/
public class ScrollApplication extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage) {
Group group = new Group();
// create canvas
PannableCanvas canvas = new PannableCanvas();
// we don't want the canvas on the top/left in this example => just
// translate it a bit
canvas.setTranslateX(100);
canvas.setTranslateY(100);
// create sample nodes which can be dragged
NodeGestures nodeGestures = new NodeGestures(canvas);
Label label1 = new Label("Draggable node 1");
label1.setTranslateX(10);
label1.setTranslateY(10);
label1.addEventFilter(MouseEvent.MOUSE_PRESSED, nodeGestures.getOnMousePressedEventHandler());
label1.addEventFilter(MouseEvent.MOUSE_DRAGGED, nodeGestures.getOnMouseDraggedEventHandler());
Label label2 = new Label("Draggable node 2");
label2.setTranslateX(100);
label2.setTranslateY(100);
label2.addEventFilter(MouseEvent.MOUSE_PRESSED, nodeGestures.getOnMousePressedEventHandler());
label2.addEventFilter(MouseEvent.MOUSE_DRAGGED, nodeGestures.getOnMouseDraggedEventHandler());
Label label3 = new Label("Draggable node 3");
label3.setTranslateX(200);
label3.setTranslateY(200);
label3.addEventFilter(MouseEvent.MOUSE_PRESSED, nodeGestures.getOnMousePressedEventHandler());
label3.addEventFilter(MouseEvent.MOUSE_DRAGGED, nodeGestures.getOnMouseDraggedEventHandler());
Circle circle1 = new Circle(300, 300, 50);
circle1.setStroke(Color.ORANGE);
circle1.setFill(Color.ORANGE.deriveColor(1, 1, 1, 0.5));
circle1.addEventFilter(MouseEvent.MOUSE_PRESSED, nodeGestures.getOnMousePressedEventHandler());
circle1.addEventFilter(MouseEvent.MOUSE_DRAGGED, nodeGestures.getOnMouseDraggedEventHandler());
Rectangle rect1 = new Rectangle(100,100);
rect1.setTranslateX(450);
rect1.setTranslateY(450);
rect1.setStroke(Color.BLUE);
rect1.setFill(Color.BLUE.deriveColor(1, 1, 1, 0.5));
rect1.addEventFilter(MouseEvent.MOUSE_PRESSED, nodeGestures.getOnMousePressedEventHandler());
rect1.addEventFilter(MouseEvent.MOUSE_DRAGGED, nodeGestures.getOnMouseDraggedEventHandler());
canvas.getChildren().addAll(label1, label2, label3, circle1, rect1);
group.getChildren().add(canvas);
// create scene which can be dragged and zoomed
Scene scene = new Scene(group, 1024, 768);
SceneGestures sceneGestures = new SceneGestures(canvas);
scene.addEventFilter(MouseEvent.MOUSE_PRESSED, sceneGestures.getOnMousePressedEventHandler());
scene.addEventFilter(MouseEvent.MOUSE_DRAGGED, sceneGestures.getOnMouseDraggedEventHandler());
scene.addEventFilter(ScrollEvent.ANY, sceneGestures.getOnScrollEventHandler());
stage.setScene(scene);
stage.show();
canvas.addGrid();
}
}
Es ist offensichtlich etwas falsch mit dem Drehpunkt Berechnung, aber ich kann nicht herausfinden, was es ist und wie man es beheben.
Vielen Dank!
Vielen Dank für die schnelle Lösung. Es funktioniert wie erwartet :-) – Roland
Vielen Dank für das Update. Ich werde das definitiv benutzen. – Roland
Scheint, dass das Delta sehr von den Mausradeinstellungen abhängt. Ich habe. G. ein Bildschirm mit sehr hoher Auflösung und daher ein hoher Mausrad-Scroll-Wert. Wenn ich Ihren Code verwende und auszoomen, erhalte ich sofort einen Bereich von ~ 100x100 Pixeln. Ich denke also, man muss den Multiplikator mit getDeltaX() und getDeltaY() betrachten oder ein festes Delta verwenden. – Roland