Graphics and Java 2D - Java: How to Program Early Objects - page 589

•Method paintComponent can be used to draw graphics in any JComponent component.
•Method paintComponent receives a Graphics object that is passed to the method by the system
when a lightweight Swing component needs to be repainted.
• When an application executes, the application container calls method paintComponent . For
paintComponent to be called again, an event must occur.
•When a JComponent is displayed, its paintComponent method is called.
•Caing method repaint (p. 559) on a component updates the graphics drawn on that component.
Section 13.3 Color Control
• Class Color (p. 559) declares methods and constants for manipulating colors in a Java program.
• Every color is created from a red, a green and a blue component. Together these components are
called RGB values (p. 560). The RGB components specify the amount of red, green and blue in
a color, respectively. The larger the value, the greater the amount of that particular color.
• Color methods getRed , getGreen and getBlue (p. 560) return int values from 0 to 255 repre-
senting the amount of red, green and blue, respectively.
• Graphics method getColor ( p. 560) returns a Color object with the current drawing color.
• Graphics method setColor ( p. 560) sets the current drawing color.
• Graphics method fillRect (p. 560) draws a rectangle filled by the Graphics object's current color.
• Graphics method drawString (p. 562) draws a String in the current color.
•The JColorChooser GUI component (p. 563) enables application users to select colors.
• JColorChooser static method showDialog (p. 564) displays a modal JColorChooser dialog.
Section 13.4 Manipulating Fonts
• Class Font (p. 566) contains methods and constants for manipulating fonts.
• Class Font 's constructor takes three arguments—the font name (p. 567) , font style and font size.
•A Font 's font style can be Font.PLAIN , Font.ITALIC or Font.BOLD (each is a static field of class
Font ). Font styles can be used in combination (e.g., Font.ITALIC + Font.BOLD ).
• The font size is measured in points. A point is 1/72 of an inch.
• Graphics method setFont (p. 567) sets the drawing font in which text will be displayed.
• Font method getSize ( p. 567) returns the font size in points.
• Font method getName ( p. 567) returns the current font name as a string.
• Font method getStyle ( p. 569) returns an integer value representing the current Font 's style.
• Font method getFamily ( p. 569) returns the name of the font family to which the current font
belongs. The name of the font family is platform specific.
• Class FontMetrics (p. 569) contains methods for obtaining font information.
• Font metrics (p. 569) include height, descent and leading.
Section 13.5 Drawing Lines, Rectangles and Ovals
• Graphics methods fillRoundRect (p. 573) and drawRoundRect (p. 573) draw rectangles with
rounded corners.
• Graphics methods draw3DRect (p. 575) and fill3DRect (p. 575) draw three-dimensional rect-
angles.
• Graphics methods drawOval (p. 575) and fillOval (p. 575) draw ovals.