如何在画布上绘制东西javafx

Question

I'm beginner of javafx: I am developing a graphical user interface using javafx and Scene builder that has a coordinate plane with x axis and y axis. It should be like this: https://postimg.cc/image/98k9mvnb3/ when someone do a mouse click anywhere on this coordinate plane it will show the coordinate point(x,y) of the pixel on the console and there will a mark(like point or some text will be written) on the same place where mouse clicked.

For implementing these things I have to use canvas & i'm able to get the coordinate point but i'm not getting how to draw the coordinate plane and how to write something on the pixel where mouse clicked.

Here is my code: Controller Class package application;

import java.net.URL;
import java.util.ResourceBundle;

import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.canvas.Canvas;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.AnchorPane;
public class AxisController implements Initializable{
    @FXML
    private AnchorPane anchr;
    @FXML 
    private Canvas canvas;
    @Override
    public void initialize(URL location, ResourceBundle resources) {
         assert canvas != null : "fx:id=\"canvas\" was not injected: check your FXML file 'AxisFxml.fxml'.";
    }

    @FXML
    private void handleMouse(MouseEvent event){
        System.out.println(event.getX());
        System.out.println(event.getY());
    }   
}

Main Class:

package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
public class AxisMain extends Application {
    @Override
    public void start(Stage primaryStage) {
        try {
            AnchorPane root = FXMLLoader.load(getClass().getResource("/application/AxisFxml.fxml"));
            Scene scene = new Scene(root,400,400);
            scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

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

Answer 1

Have you tried something as simple as putting some code like this into your handleMouse method?

GraphicsContext gc = canvas.getGraphicsContext2D();

gc.setFill(Color.BLUE);
gc.fillRect(event.getX()-5,event.getY()-5,10,10);

This assumes of course that you have also attached this method to the canvas so that you actually get the events in the right coordinate system.