Learning Java

The Rendering Pipeline

One of the strengths of the 2D API is that shapes, text, and images are manipulated in many of the same ways. In this section, we’ll describe what happens to shapes, text, and images after you give them to a Graphics2D. Rendering is the process of taking some collection of shapes, text, and images and figuring out how to represent them by coloring pixels on a screen or printer. Graphics2D supports four rendering operations:

1. Draw the outline of a shape, with the draw( ) method.

2. Fill the interior of a shape, with the fill( ) method.

3. Draw some text, with the drawString( ) method.

4. Draw an image, with any of the many forms of the drawImage( ) method.

The graphics context instantiated by a Graphics2D object consists of the following fields, whose values are controlled by various accessor methods:

paint

The current paint (an object of type java.awt.Paint) determines what colors will be used to fill a shape. This affects shape outlines and text, as well. You can change the current paint using Graphics2D ’s setPaint( ) method. Note that the Color class implements the Paint interface, so you can pass Colors to setPaint( ) if you want to use solid colors.

stroke

Graphics2D uses the current stroke for shapes that are passed to its draw( ) method. The outline of the shape is represented by another shape that is determined by the current stroke. The resulting shape (the stroked outline) is then filled. Suppose you wanted to draw the outline of a circle. If the current stroke ...