Java How to Program, Early Objects, 11th Edition

22.10 Drawing on a Canvas

So far, you’ve displayed and manipulated JavaFX two-dimensional shape objects that reside in the scene graph. In this section, we demonstrate similar drawing capabilities using the javafx.scene.canvas package, which contains two classes:

• Class Canvas is a subclass of Node in which you can draw graphics.

• Class GraphicsContext performs the drawing operations on a Canvas.

As you’ll see, a GraphicsContext object enables you to specify the same drawing characteristics that you’ve previously used on Shape objects. However, with a GraphicsContext, you must set these characteristics and draw the shapes programmatically. To demonstrate various Canvas capabilities, Fig. 22.15 re-implements Section 22.3’s BasicShapes example. ...