JavaFX | Canvas Class

Canvas class is a part of JavaFX. Canvas class basically creates an image that can be drawn on using a set of graphics commands provided by a GraphicsContext. Canvas has a specified height and width and all the drawing operations are clipped to the bounds of the canvas.

Constructors of the class:

1. Canvas(): Creates a new canvas object.
2. Canvas(double w, double h): Creates a new canvas object with specified width and height.

Commonly Used Methods:

Below programs illustrate the use of Canvas class:

1. Java Program to create a canvas with specified width and height(as arguments of constructor), add it to the stage and also add a circle and rectangle on it: In this program we will create a Canvas named canvas with specified width and height. We will extract the GraphicsContext using the getGraphicsContext2D() function and draw a rectangle and a oval of different color. Now we will create a Group named group and add the canvas to the group. Now create a scene and add the group to the scene and then attach the scene to the stage and call the show() function to display the results.

   
   

   
   
   

   // Java Program to create a canvas with specified // width and height(as arguments of constructor), // add it to the stage and also add a circle and // rectangle on it import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.*; import javafx.scene.layout.*; import javafx.stage.Stage; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.scene.canvas.*; import javafx.scene.paint.Color; import javafx.scene.Group;    public class canvas extends Application {        // launch the application     public void start(Stage stage)     {            // set title for the stage         stage.setTitle("creating canvas");            // create a canvas         Canvas canvas = new Canvas(100.0f, 100.0f);            // graphics context         GraphicsContext graphics_context =               canvas.getGraphicsContext2D();            // set fill for rectangle         graphics_context.setFill(Color.RED);         graphics_context.fillRect(20, 20, 70, 70);            // set fill for oval         graphics_context.setFill(Color.BLUE);         graphics_context.fillOval(30, 30, 70, 70);            // create a Group         Group group = new Group(canvas);            // create a scene         Scene scene = new Scene(group, 200, 200);            // set the scene         stage.setScene(scene);            stage.show();     }        // Main Method     public static void main(String args[])     {            // launch the application         launch(args);     } }

   Output:

   

2. Java Program to create a canvas and use setHeight() and setWidth() function to set canvas size and add it to the stage and also add a circle and rectangle on it: In this program we will create a Canvas named canvas and set the width and height using the setWidth() and setHeight() function. We will extract the GraphicsContext using the getGraphicsContext2D() function and draw two rectangles and a oval of different color. We will create a Group named group and add the canvas to the group. We will create a scene and add the group to the scene and then attach the scene to the stage. Finally, call the show() function to display the results.

   
   

   
   
   

   // Java Program to create a canvas and use  // setHeight() and setWidth() function to // set canvas size and add it to the stage // and also add a circle and rectangle on it import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.*; import javafx.scene.layout.*; import javafx.stage.Stage; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.scene.canvas.*; import javafx.scene.paint.Color; import javafx.scene.Group;    public class canvas1 extends Application {        // launch the application     public void start(Stage stage)     {            // set title for the stage         stage.setTitle("creating canvas");            // create a canvas         Canvas canvas = new Canvas();            // set height and width         canvas.setHeight(400);         canvas.setWidth(400);            // graphics context         GraphicsContext graphics_context =              canvas.getGraphicsContext2D();            // set fill for rectangle         graphics_context.setFill(Color.PINK);         graphics_context.fillRect(40, 40, 100, 100);            // set fill for rectangle         graphics_context.setFill(Color.RED);         graphics_context.fillRect(20, 20, 70, 70);            // set fill for oval         graphics_context.setFill(Color.BLUE);         graphics_context.fillOval(30, 30, 70, 70);            // create a Group         Group group = new Group(canvas);            // create a scene         Scene scene = new Scene(group, 400, 400);            // set the scene         stage.setScene(scene);            stage.show();     }        // Main Method     public static void main(String args[])     {            // launch the application         launch(args);     } }

   Output:

   

Note: The above programs might not run in an online IDE. Please use an offline compiler.

Reference: https://docs.oracle.com/javase/8/javafx/api/javafx/scene/canvas/Canvas.html