用Javafx实现汽车上雨刷器摆动的动画（雨刷器用画线描绘）

以下是一个简单的实现汽车上雨刷器摆动的动画的 Javafx 代码示例，其中雨刷器用画线描绘：

import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Duration;

public class CarWindShieldWiper extends Application {

    private static final int WINDOW_WIDTH = 800;
    private static final int WINDOW_HEIGHT = 600;
    private static final int CANVAS_WIDTH = 600;
    private static final int CANVAS_HEIGHT = 400;
    private static final int WIPER_LENGTH = 60;
    private static final int WIPER_WIDTH = 5;
    private static final int WIPER_SPEED = 5;

    private int angle = 0;
    private boolean reverse = false;

    @Override
    public void start(Stage primaryStage) throws Exception {
        Canvas canvas = new Canvas(CANVAS_WIDTH, CANVAS_HEIGHT);
        GraphicsContext gc = canvas.getGraphicsContext2D();
        Group root = new Group(canvas);

        Timeline timeline = new Timeline(new KeyFrame(Duration.millis(100), event -> {
            animateWiper(gc);
        }));
        timeline.setCycleCount(Animation.INDEFINITE);
        timeline.play();

        Scene scene = new Scene(root, WINDOW_WIDTH, WINDOW_HEIGHT);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void animateWiper(GraphicsContext gc) {
        gc.clearRect(0, 0, CANVAS_WIDTH, CANVAS_HEIGHT);
        gc.setStroke(Color.BLACK);
        gc.setLineWidth(2);

        // 绘制雨刷器底部
        gc.strokeLine(CANVAS_WIDTH / 2 - WIPER_LENGTH / 2, CANVAS_HEIGHT - WIPER_WIDTH, CANVAS_WIDTH / 2 + WIPER_LENGTH / 2, CANVAS_HEIGHT - WIPER_WIDTH);
        gc.setFill(Color.GRAY);
        gc.fillRect(CANVAS_WIDTH / 2 - WIPER_LENGTH / 2, CANVAS_HEIGHT - WIPER_WIDTH, WIPER_LENGTH, WIPER_WIDTH);

        // 绘制雨刷器
        gc.setStroke(Color.BLACK);
        gc.setLineWidth(3);
        int x1 = CANVAS_WIDTH / 2;
        int y1 = CANVAS_HEIGHT - WIPER_WIDTH;
        int x2 = (int) (x1 + WIPER_LENGTH * Math.cos(Math.toRadians(angle)));
        int y2 = (int) (y1 - WIPER_LENGTH * Math.sin(Math.toRadians(angle)));
        gc.strokeLine(x1, y1, x2, y2);

        // 更新角度
        if (reverse) {
            angle -= WIPER_SPEED;
            if (angle < -45) {
                reverse = false;
            }
        } else {
            angle += WIPER_SPEED;
            if (angle > 45) {
                reverse = true;
            }
        }
    }

    public static void main(String[] args) {
        launch(args);
    }

}

在这个示例中，我们使用 `Canvas` 类创建了一个画布，并在画布上绘制了雨刷器。`Timeline` 类用于控制动画的运行，我们在每个时间步长上更新雨刷器的位置和旋转角度。通过改变旋转角度，我们可以实现雨刷器的摆动效果。