Java 2D Graphics

7.1. Using the TextLayout Class

The drawString() methods render simple pieces of text. If you're interested in support for a caret (cursor) and highlighting, you'll need to use the java.awt.font.TextLayout class. This class can be used as the basis for a sophisticated text editor. Most applications don't need the power of this customization and can simply use JTextField, JTextArea, or JEditorPane.

TextLayout offers the following features:

• text metrics

• hit testing

• caret support

• highlighting support

• paragraph layout on multiple lines (with the help of the LineBreakMeasurer class)

7.1.1. TextLayout Basics

Creating a TextLayout is pretty simple. You just need to supply the text itself, either as a string or a character iterator, and a FontRenderContext (which was described in Chapter 6):

public TextLayout(String string, Font font, FontRenderContext frc)

Use this constructor to create a TextLayout using the supplied string and font.

public TextLayout(String string, Map attributes, FontRenderContext frc)

This constructor creates a new TextLayout from the given string. The supplied attributes are applied to the entire string. (For a list of possible attributes, see Table 6-1.)

public TextLayout(AttributedCharacterIterator text, FontRenderContext frc)

This constructor creates a TextLayout from the supplied iterator.

Once you've created a TextLayout, you can render it by calling its draw() method. This is a little different from the usual model. Usually you create something, like a shape ...