JavaFX画出汽车雨刮器，并且可以进行升档降档来调节速度

下面是一个简单的JavaFX程序，用于绘制汽车雨刮器和调节速度：

import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class CarWindshieldWiper extends Application {

    private static final int WIDTH = 400;
    private static final int HEIGHT = 400;
    private static final int WIPER_SPEED = 10;
    private static final int MAX_SPEED = 5;

    private int currentSpeed = 1;
    private boolean isGoingUp = true;

    @Override
    public void start(Stage primaryStage) {

        Canvas canvas = new Canvas(WIDTH, HEIGHT);
        GraphicsContext gc = canvas.getGraphicsContext2D();

        AnimationTimer timer = new AnimationTimer() {
            long lastUpdate = 0;

            @Override
            public void handle(long now) {
                if (lastUpdate != 0) {
                    long elapsedNanoSeconds = now - lastUpdate;
                    double elapsedSeconds = elapsedNanoSeconds / 1_000_000_000.0;

                    gc.clearRect(0, 0, WIDTH, HEIGHT);
                    drawWindshield(gc);
                    updateWiperPosition(elapsedSeconds);
                    drawWiper(gc);
                }
                lastUpdate = now;
            }
        };
        timer.start();

        StackPane root = new StackPane(canvas);
        Scene scene = new Scene(root);

        scene.setOnKeyPressed(event -> {
            switch (event.getCode()) {
                case UP:
                    if (currentSpeed < MAX_SPEED) {
                        currentSpeed++;
                    }
                    break;
                case DOWN:
                    if (currentSpeed > 1) {
                        currentSpeed--;
                    }
                    break;
                default:
                    break;
            }
        });

        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void drawWindshield(GraphicsContext gc) {
        gc.setFill(Color.BLUE);
        gc.fillRect(50, 50, 300, 200);
        gc.setFill(Color.GRAY);
        gc.fillOval(100, 100, 200, 100);
    }

    private void updateWiperPosition(double elapsedSeconds) {
        double deltaPosition = currentSpeed * WIPER_SPEED * elapsedSeconds;

        if (isGoingUp) {
            Wiper.getInstance().moveUp(deltaPosition);
        } else {
            Wiper.getInstance().moveDown(deltaPosition);
        }

        if (Wiper.getInstance().getY() < 75) {
            isGoingUp = false;
        } else if (Wiper.getInstance().getY() > 225) {
            isGoingUp = true;
        }
    }

    private void drawWiper(GraphicsContext gc) {
        gc.setFill(Color.WHITE);
        gc.fillRect(Wiper.getInstance().getX(), Wiper.getInstance().getY(), 75, 5);
    }

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

    private static class Wiper {
        private static final Wiper INSTANCE = new Wiper();

        private double x = 100;
        private double y = 150;

        private Wiper() {}

        public static Wiper getInstance() {
            return INSTANCE;
        }

        public double getX() {
            return x;
        }

        public double getY() {
            return y;
        }

        public void moveUp(double delta) {
            y -= delta;
        }

        public void moveDown(double delta) {
            y += delta;
        }
    }
}

这个程序使用JavaFX的Canvas绘制汽车雨刮器和雨刮器的位置。程序使用AnimationTimer类来更新雨刮器的位置，并使用按键事件来调整速度。Wiper类是一个单例，用于跟踪雨刮器的位置。