Learning Java, 4th Edition

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 object. 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:

• Draw a shape’s outline with the draw() method.

• Fill a shape’s interior with the fill() method.

• Draw some text with the drawString() method.

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

The graphics context represented by a Graphics2D object holds the following properties, whose values are controlled by corresponding accessor methods—for example, getFont() and setFont():

Paint

The current paint (an object of type java.awt.Paint) determines what color or pattern will be used to fill a shape. This affects the drawing of 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 stroke to determine how to draw the outline of shapes that are passed to its draw() method. In graphics terminology, to “stroke” a shape means to take a path defined by the shape and effectively trace it with a pen or brush of a certain size and characteristics. ...