旋转形状JAVAFX

Question

将其变成一般性问题。 如何绕枢轴旋转线？

Answer 1

解决了！一杯好咖啡有帮助！

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package rotateline;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import static javafx.scene.input.KeyCode.ENTER;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.AnchorPane;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Line;
import javafx.scene.shape.Shape;
import javafx.stage.Stage;

/**
 *
 * @author melkhaldi
 */
public class RotateLine extends Application {
Circle pivot;
Line line;
@Override
public void start(Stage primaryStage) {
    //make a visal representation of rotation center
     pivot = new Circle(0, 0, 8);
    pivot.setTranslateX(50);
    pivot.setTranslateY(50);

    //draw a red line (rotated)--using pivot location as start point.
     line = new Line(50, 50, 200, 200);
    line.setStyle("-fx-stroke: red; -fx-stroke-width: 3;");

    //horizontal line (fixed).
    Line horizontaLine = new Line(50, 50, 200, 50);
    horizontaLine.setStrokeWidth(1);

    //label to display angle between mouse cursor and horizontal line.
    String prefixMouse = "Angle <Mouse -Pivot - Horizontal Line> is: ";
    Label mouseAngleReporter = new Label(prefixMouse);
    mouseAngleReporter.setLayoutY(300);

    //label to display angle between rotated red line, pivot, and hosizontal fixed line.
    String prefixLine = "Angle <Red Line -Pivot - Horizontal Line> is: ";
    Label lineAngleReporter = new Label(prefixLine);
    lineAngleReporter.setLayoutY(400);

    TextField rotateField = new TextField("Enter degree angle and hit enter");
    rotateField.setLayoutY(200);
    //add to root and scene
    AnchorPane root = new AnchorPane();
    root.getChildren().add(line);
    root.getChildren().add(horizontaLine);
    root.getChildren().add(pivot);
    root.getChildren().add(mouseAngleReporter);
    root.getChildren().add(lineAngleReporter);
    root.getChildren().add(rotateField);
    Scene scene = new Scene(root, 450, 450);

    primaryStage.setTitle("Rotate Line");
    primaryStage.setScene(scene);
    primaryStage.show();

    // set on mouse drag
    line.setOnMouseDragged((MouseEvent event) -> {
        double mouseDeltaX = event.getSceneX() - pivot.getTranslateX();
        double mouseDeltaY = event.getSceneY() - pivot.getTranslateY();
        double radAngle = Math.atan2(mouseDeltaY, mouseDeltaX);
        double[] res = rotateLine(pivot, radAngle - Math.toRadians(lineCurrentAngle()), line.getEndX(), line.getEndY());

        line.setEndX(res[0]);
        line.setEndY(res[1]);

        mouseAngleReporter.setText(prefixMouse + Math.toDegrees(radAngle));
        lineAngleReporter.setText(prefixLine + lineCurrentAngle());
    });

    rotateField.setOnKeyPressed((e) -> {
        if (e.getCode().equals(ENTER)) {
            if (rotateField.getText().matches("\\b\\d+\\b")) {
                //subtract line current angle to make rotation absolute
                double radAngle = Math.toRadians(Double.valueOf(rotateField.getText()) - lineCurrentAngle());

                double[] res = rotateLine(pivot, radAngle, line.getEndX(), line.getEndY());

                line.setEndX(res[0]);
                line.setEndY(res[1]);
            }
        }
    });
}

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    launch(args);
}

private double lineCurrentAngle(){
    return  Math.toDegrees(Math.atan2(line.getEndY() - pivot.getTranslateY(), line.getEndX() - pivot.getTranslateX()));
}
private double[] rotateLine(Shape pivot, double radAngle, double endX, double endY) {
    double x, y;
    x = Math.cos(radAngle) * (endX - pivot.getTranslateX()) - Math.sin(radAngle) * (endY - pivot.getTranslateY()) + pivot.getTranslateX();
    y = Math.sin(radAngle) * (endX - pivot.getTranslateX()) + Math.cos(radAngle) * (endY - pivot.getTranslateY()) + pivot.getTranslateY();
    return new double[]{x, y};
}

}