我正在尝试使用ScrollPane实现一个场景，用户可以在其中拖动一个节点并动态缩放它。我使用鼠标滚轮进行拖动和缩放以及重置缩放，但是我在计算上遇到问题以使节点适合父节点的宽度。
这是我的代码sscce。
如果我放大或缩小或更改窗口大小，则适合宽度不起作用。
如果有人可以帮助我进行计算以使节点适合父母的宽度，我将非常感激。
编辑：
fitWidth()，可以通过鼠标右键双击来调用。希望现在更清楚了。
import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.ScrollPane.ScrollBarPolicy;
import javafx.scene.input.MouseButton;
import javafx.scene.input.MouseEvent;
import javafx.scene.input.ScrollEvent;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.StrokeType;
import javafx.stage.Stage;
import javafx.util.Duration;
public class ZoomAndPanExample extends Application {
private ScrollPane scrollPane = new ScrollPane();
private final DoubleProperty zoomProperty = new SimpleDoubleProperty(1.0d);
private final DoubleProperty deltaY = new SimpleDoubleProperty(0.0d);
private final Group group = new Group();
public static void main(String[] args) {
Application.launch(args);
}
@Override
public void start(Stage primaryStage) {
scrollPane.setPannable(true);
scrollPane.setHbarPolicy(ScrollBarPolicy.NEVER);
scrollPane.setVbarPolicy(ScrollBarPolicy.NEVER);
AnchorPane.setTopAnchor(scrollPane, 10.0d);
AnchorPane.setRightAnchor(scrollPane, 10.0d);
AnchorPane.setBottomAnchor(scrollPane, 10.0d);
AnchorPane.setLeftAnchor(scrollPane, 10.0d);
AnchorPane root = new AnchorPane();
Rectangle rect = new Rectangle(80, 60);
rect.setStroke(Color.NAVY);
rect.setFill(Color.NAVY);
rect.setStrokeType(StrokeType.INSIDE);
group.getChildren().add(rect);
// create canvas
PanAndZoomPane panAndZoomPane = new PanAndZoomPane();
zoomProperty.bind(panAndZoomPane.myScale);
deltaY.bind(panAndZoomPane.deltaY);
panAndZoomPane.getChildren().add(group);
SceneGestures sceneGestures = new SceneGestures(panAndZoomPane);
scrollPane.setContent(panAndZoomPane);
panAndZoomPane.toBack();
scrollPane.addEventFilter( MouseEvent.MOUSE_CLICKED, sceneGestures.getOnMouseClickedEventHandler());
scrollPane.addEventFilter( MouseEvent.MOUSE_PRESSED, sceneGestures.getOnMousePressedEventHandler());
scrollPane.addEventFilter( MouseEvent.MOUSE_DRAGGED, sceneGestures.getOnMouseDraggedEventHandler());
scrollPane.addEventFilter( ScrollEvent.ANY, sceneGestures.getOnScrollEventHandler());
root.getChildren().add(scrollPane);
Scene scene = new Scene(root, 600, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
class PanAndZoomPane extends Pane {
public static final double DEFAULT_DELTA = 1.3d;
DoubleProperty myScale = new SimpleDoubleProperty(1.0);
public DoubleProperty deltaY = new SimpleDoubleProperty(0.0);
private Timeline timeline;
public PanAndZoomPane() {
this.timeline = new Timeline(60);
// add scale transform
scaleXProperty().bind(myScale);
scaleYProperty().bind(myScale);
}
public double getScale() {
return myScale.get();
}
public void setScale( double scale) {
myScale.set(scale);
}
public void setPivot( double x, double y, double scale) {
// note: pivot value must be untransformed, i. e. without scaling
// timeline that scales and moves the node
timeline.getKeyFrames().clear();
timeline.getKeyFrames().addAll(
new KeyFrame(Duration.millis(200), new KeyValue(translateXProperty(), getTranslateX() - x)),
new KeyFrame(Duration.millis(200), new KeyValue(translateYProperty(), getTranslateY() - y)),
new KeyFrame(Duration.millis(200), new KeyValue(myScale, scale))
);
timeline.play();
}
/**
* !!!! The problem is in this method !!!!
*
* The calculations are incorrect, and result in unpredictable behavior
*
*/
public void fitWidth () {
double scale = getParent().getLayoutBounds().getMaxX()/getLayoutBounds().getMaxX();
double oldScale = getScale();
double f = (scale / oldScale)-1;
double dx = getTranslateX() - getBoundsInParent().getMinX() - getBoundsInParent().getWidth()/2;
double dy = getTranslateY() - getBoundsInParent().getMinY() - getBoundsInParent().getHeight()/2;
double newX = f*dx + getBoundsInParent().getMinX();
double newY = f*dy + getBoundsInParent().getMinY();
setPivot(newX, newY, scale);
}
public void resetZoom () {
double scale = 1.0d;
double x = getTranslateX();
double y = getTranslateY();
setPivot(x, y, scale);
}
public double getDeltaY() {
return deltaY.get();
}
public void setDeltaY( double dY) {
deltaY.set(dY);
}
}
/**
* Mouse drag context used for scene and nodes.
*/
class DragContext {
double mouseAnchorX;
double mouseAnchorY;
double translateAnchorX;
double translateAnchorY;
}
/**
* Listeners for making the scene's canvas draggable and zoomable
*/
public class SceneGestures {
private DragContext sceneDragContext = new DragContext();
PanAndZoomPane panAndZoomPane;
public SceneGestures( PanAndZoomPane canvas) {
this.panAndZoomPane = canvas;
}
public EventHandler<MouseEvent> getOnMouseClickedEventHandler() {
return onMouseClickedEventHandler;
}
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) {
sceneDragContext.mouseAnchorX = event.getX();
sceneDragContext.mouseAnchorY = event.getY();
sceneDragContext.translateAnchorX = panAndZoomPane.getTranslateX();
sceneDragContext.translateAnchorY = panAndZoomPane.getTranslateY();
}
};
private EventHandler<MouseEvent> onMouseDraggedEventHandler = new EventHandler<MouseEvent>() {
public void handle(MouseEvent event) {
panAndZoomPane.setTranslateX(sceneDragContext.translateAnchorX + event.getX() - sceneDragContext.mouseAnchorX);
panAndZoomPane.setTranslateY(sceneDragContext.translateAnchorY + event.getY() - 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 = PanAndZoomPane.DEFAULT_DELTA;
double scale = panAndZoomPane.getScale(); // currently we only use Y, same value is used for X
double oldScale = scale;
panAndZoomPane.setDeltaY(event.getDeltaY());
if (panAndZoomPane.deltaY.get() < 0) {
scale /= delta;
} else {
scale *= delta;
}
double f = (scale / oldScale)-1;
double dx = (event.getX() - (panAndZoomPane.getBoundsInParent().getWidth()/2 + panAndZoomPane.getBoundsInParent().getMinX()));
double dy = (event.getY() - (panAndZoomPane.getBoundsInParent().getHeight()/2 + panAndZoomPane.getBoundsInParent().getMinY()));
panAndZoomPane.setPivot(f*dx, f*dy, scale);
event.consume();
}
};
/**
* Mouse click handler
*/
private EventHandler<MouseEvent> onMouseClickedEventHandler = new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
if (event.getButton().equals(MouseButton.PRIMARY)) {
if (event.getClickCount() == 2) {
panAndZoomPane.resetZoom();
}
}
if (event.getButton().equals(MouseButton.SECONDARY)) {
if (event.getClickCount() == 2) {
panAndZoomPane.fitWidth();
}
}
}
};
}
}
答案 0 :(得分：2)
我找到了答案。我正在查看错误的计算，假设它与翻译有关。真正的罪魁祸首是计算尺度差异。我只是改变了这个：
double f = (scale / oldScale)-1;
到此：
double f = scale - oldScale;