在第2步的基础上设计实现一个具有GUI界面的几何图形绘制系统系统，要求实现根据选择的几何图形类型来绘制和删除相应的图形，其中相关参数应通过界面输入，并可计算图形的周长和面积。 javafx代码

好的，以下是一个使用JavaFX实现的几何图形绘制系统的代码示例，包括圆形、矩形和三角形：

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.Shape;
import javafx.scene.shape.Polygon;
import javafx.stage.Stage;

public class GeometryDrawer extends Application {
    private Shape currentShape;  // 当前绘制的图形
    private Pane canvas;  // 画布
    private TextField param1Field;  // 参数1输入框
    private TextField param2Field;  // 参数2输入框
    private Label perimeterLabel;  // 周长标签
    private Label areaLabel;  // 面积标签

    @Override
    public void start(Stage primaryStage) {
        // 创建画布
        canvas = new Pane();
        canvas.setPrefWidth(600);
        canvas.setPrefHeight(400);

        // 创建参数输入框
        param1Field = new TextField();
        param1Field.setPrefWidth(100);
        param2Field = new TextField();
        param2Field.setPrefWidth(100);

        // 创建周长和面积标签
        perimeterLabel = new Label();
        areaLabel = new Label();

        // 创建按钮
        Button circleBtn = new Button("圆形");
        circleBtn.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                createCircle();
            }
        });
        Button rectangleBtn = new Button("矩形");
        rectangleBtn.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                createRectangle();
            }
        });
        Button triangleBtn = new Button("三角形");
        triangleBtn.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                createTriangle();
            }
        });
        Button deleteBtn = new Button("删除");
        deleteBtn.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                deleteShape();
            }
        });

        // 将控件添加到容器中
        Pane controlPane = new Pane();
        controlPane.getChildren().addAll(circleBtn, rectangleBtn, triangleBtn, param1Field, param2Field, deleteBtn, perimeterLabel, areaLabel);
        circleBtn.setLayoutX(10);
        circleBtn.setLayoutY(10);
        rectangleBtn.setLayoutX(90);
        rectangleBtn.setLayoutY(10);
        triangleBtn.setLayoutX(170);
        triangleBtn.setLayoutY(10);
        param1Field.setLayoutX(10);
        param1Field.setLayoutY(50);
        param2Field.setLayoutX(120);
        param2Field.setLayoutY(50);
        deleteBtn.setLayoutX(240);
        deleteBtn.setLayoutY(10);
        perimeterLabel.setLayoutX(10);
        perimeterLabel.setLayoutY(90);
        areaLabel.setLayoutX(10);
        areaLabel.setLayoutY(110);

        // 创建场景
        Scene scene = new Scene(new Pane(canvas, controlPane));

        // 设置主舞台
        primaryStage.setTitle("几何图形绘制系统");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    // 创建圆形
    private void createCircle() {
        double radius = Double.parseDouble(param1Field.getText());
        Circle circle = new Circle(radius);
        circle.setLayoutX(300);
        circle.setLayoutY(200);
        canvas.getChildren().add(circle);
        currentShape = circle;
        updatePerimeterAndArea();
    }

    // 创建矩形
    private void createRectangle() {
        double width = Double.parseDouble(param1Field.getText());
        double height = Double.parseDouble(param2Field.getText());
        Rectangle rectangle = new Rectangle(width, height);
        rectangle.setLayoutX(300 - width / 2);
        rectangle.setLayoutY(200 - height / 2);
        canvas.getChildren().add(rectangle);
        currentShape = rectangle;
        updatePerimeterAndArea();
    }

    // 创建三角形
    private void createTriangle() {
        double side = Double.parseDouble(param1Field.getText());
        double height = Double.parseDouble(param2Field.getText());
        double[] points = new double[] {
                300, 200 - height / 3 * 2,
                300 - side / 2, 200 + height / 3,
                300 + side / 2, 200 + height / 3
        };
        Polygon triangle = new Polygon(points);
        canvas.getChildren().add(triangle);
        currentShape = triangle;
        updatePerimeterAndArea();
    }

    // 删除图形
    private void deleteShape() {
        if (currentShape != null) {
            canvas.getChildren().remove(currentShape);
            currentShape = null;
            updatePerimeterAndArea();
        }
    }

    // 更新周长和面积标签
    private void updatePerimeterAndArea() {
        if (currentShape instanceof Circle) {
            Circle circle = (Circle) currentShape;
            double perimeter = 2 * Math.PI * circle.getRadius();
            double area = Math.PI * circle.getRadius() * circle.getRadius();
            perimeterLabel.setText("周长：" + perimeter);
            areaLabel.setText("面积：" + area);
        } else if (currentShape instanceof Rectangle) {
            Rectangle rectangle = (Rectangle) currentShape;
            double perimeter = 2 * (rectangle.getWidth() + rectangle.getHeight());
            double area = rectangle.getWidth() * rectangle.getHeight();
            perimeterLabel.setText("周长：" + perimeter);
            areaLabel.setText("面积：" + area);
        } else if (currentShape instanceof Polygon) {
            Polygon triangle = (Polygon) currentShape;
            double perimeter = triangle.getStrokeDashArray().size() * (Double.parseDouble(param1Field.getText()) + Double.parseDouble(param2Field.getText()));
            double area = Double.parseDouble(param1Field.getText()) * Double.parseDouble(param2Field.getText()) / 2.0;
            perimeterLabel.setText("周长：" + perimeter);
            areaLabel.setText("面积：" + area);
        } else {
            perimeterLabel.setText("");
            areaLabel.setText("");
        }
    }

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

该程序使用了JavaFX的一些基本控件和图形类，通过按钮来选择要绘制的几何图形类型，通过文本框来输入相关参数，通过标签来显示图形的周长和面积，通过画布来绘制和删除图形。您可以根据实际需求进行修改和扩展。