本文介紹了JavaFX縮放，在ScrollPane中滾動的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我有一個帶有縮放和縮放功能的JavaFX應用程序，如下所述：
Scale at pivot point in an already scaled node
我需要實現的是把圖像放在右邊的窗格，并保持在左邊的圖像，如下圖所示。
問題
如何將此應用程序嵌入SPlitPane，左側將顯示另一個面板。
SplitPane splitPane = new SplitPane();
splitPane.getItems().add(new Label("Left Panel"));
splitPane.getItems().add(group);
Scene scene = new Scene(splitPane, 1024, 768);
遺憾的是，代碼產生了錯誤的坐標
推薦答案
要在ScrollPane內放大，需要調整滾動位置。這比僅僅追加轉換要復雜一些，如果不使用ScrollPane，則可以完成轉換。
基本上，您需要在縮放節點之前檢查當前的滾動位置，并在縮放后修改滾動位置，以防止軸心點因縮放因子的更改而更改其位置。
下面的示例不僅允許您在按住CTRL鍵的同時，在移動鼠標滾輪時調整縮放比例，還允許您在不單擊圓(可平移ScrollPane)時在網格中移動圓。
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);
}
}
這篇關于JavaFX縮放，在ScrollPane中滾動的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，
