Ivor Horton's Beginning Java®, Java 7 Edition

Chapter 19

Drawing in a Window

WHAT YOU WILL LEARN IN THIS CHAPTER:

• How you can implement Sketcher using the model/view architecture
• How coordinates are defined for drawing on a component
• How you implement drawing on a component
• How to structure the components in a window for drawing
• What kinds of shapes you can draw on a component
• How you implement mouse listener methods to enable interactive drawing operations

In this chapter you look at how you can draw using the Java 2D facilities that are part of the Java Foundation Classes (JFC). You explore how you draw on a component in an applet and in an application. You investigate how you can combine the event-handling capability that you learned about in Chapter 18 with the drawing facilities you explore in this chapter to implement an interactive graphical user interface for creating a sketch.

USING THE MODEL/VIEW ARCHITECTURE

You need to develop an idea of how you’re going to manage the data for a sketch in the Sketcher program before you start drawing a sketch, because this affects where and how you handle events. You already have a class that defines an application window, SketcherFrame, but this class would not be a very sensible place to store the underlying data that defines a sketch. For one thing, you’ll want to save a sketch in a file, and serialization is the easiest way to do that. If you’re going to use serialization to store a sketch, you don’t want all the fields in the implementation of the SketcherFrame class muddled ...