Java Programming, Second Edition

1. Java Programming, Second Edition Chapter Ten Graphics

2. In this chapter, you will: Learn about the paint() and repaint() methods Use the drawString() method to draw strings Use the setFont() and setColor() Graphic object methods Create Graphics and Graphics 2D objects Draw lines, rectangles, ovals, arcs, and polygons

3. Copy an area • Learn more about fonts and their methods • Draw with Java 2D graphics • Add sound, images, and simple animations to Swing applets

4. Learning about the paint() and repaint() Methods • paint() method- Runs when Java displays your Swing applet • Is used within every Swing applet • public void paint (Graphics g) • repaint() method- Use when a window needs to be updated, such as when it contains new images • Java system calls the repaint() method when it needs to update a window • repaint() creates a Graphics object for you

5. Using the drawString() Method to Draw Methods • drawString() method- Allows you to draw a String in a Swing applet window • Requires three arguments: • A String • An x-axis coordinate • A y-axis coordinate

6. Using the setFont() and setColor() Graphics Object Methods • setFont() and setColor() Graphics object methods- Improve the appearance of Graphics objects • setFont() method requires a Font object • Font someFont = new Font(“TimesRoman”,Font.BOLD, 16);

7. Using the setFont() and setColor() Graphics Object Methods • setColor() method- Color class contains 13 constants • Use any of these constants as an argument to the setColor() method • brush.setColor(Color.green);

9. The Swing Applets Background Color setBackground() • setBackground(Color.pink); • Change the background color of your Swing applet • You do not need a Graphics object to change the Swing applet’s background color

10. Creating Graphics and Graphics 2D Objects • You can instantiate your own Graphics or Graphics 2D objects

11. Drawing Lines • drawLine() method- To draw a straight line between any two points on the screen • Takes four arguments • The x- and y-coordinates of the line’s starting point • The x- and y-coordinates of the line’s ending point • pen.drawLine(10,10,100,200);

12. Drawing Rectangles • drawRect() and fillRect() methods- To draw the outline of a rectangle or to draw a solid, or filled, rectangle • These methods require four arguments: • First two represent the x- and y-coordinates of the upper-left corner of the rectangle • Last two represent the width and height of the rectangle • drawRect(20,100,200,10);

13. Drawing Rectangles • clearRect() method- Draws a rectangle • Requires four arguments • drawRect() and fillRect() methods use the current drawing color • clearRect() method uses the current background color to draw what appears to be an empty or “clear” rectangle

14. Drawing Rectangles • drawRoundRect() method- Create rectangles with rounded corners • Requires six arguments: • x- and y-coordinates of the upper-left corner • The width and height • The arc width and height associated with the rounded corners

15. Drawing Ovals • drawOval() • fillOval() • Both draw ovals using the same four arguments that rectangles use

17. Drawing Arcs • Draw an arc using the Graphics drawArc() method • Provide six arguments: • x-coordinate of the upper-left corner of an imaginary rectangle that represents the bounds of the imaginary circle that contains the arc • y-coordinate of the same point • Width of the imaginary rectangle that represents the bounds of the imaginary circle that contains the arc • Height of the same imaginary rectangle • Beginning arc position • Arc angle

19. Drawing Arcs • fillArc() method- Creates a solid arc • Arc is drawn and two straight lines are drawn from the arc end points to the center of the imaginary circle whose perimeter the arc occupies • solidarc.fillArc(10,50,100,100,20,320); • solidarc.fillArc(200,50,100,100,340,40);

21. Creating Three-Dimensional Rectangles • draw3DRect() method- To draw a rectangle that appears to have “shadowing” on two of its edges • Requires a fifth argument in addition to the x- and y-coordinates and width and height • Fifth argument is a Boolean value • True if you want the raised rectangle effect • False if you want the lowered rectangle effect • fill3DRect() method for creating filled three-dimensional rectangles

22. Creating Polygons • drawPolygon() method- To create a shape that is more complex than a rectangle • Requires three arguments: two integer arrays and a single integer • First integer array holds a series of x-coordinate positions • Second array holds a series of corresponding y-coordinate positions • Third integer argument is the number of pairs of points you want to connect

23. Copying an Area • copyArea() method- Use to copy an area • Requires 6 parameters • x-coordinate and y-coordinate of the upper-left corner of the area to be copied • Width and height of the area to be copied • The horizontal and vertical displacement of the destination of the copy

24. Learning More about Fonts and Their Methods • getAllFonts()- Used to discover the fonts that are available on your system • Part of the GraphicsEnvironment class in the java.awt package • getScreenResolution() and getScreenSize()-Used to get the resolution and screen size of your system • getScreenResolution()- returns the number of pixels as an int type

25. Drawing with Java 2D Graphics • Java 2D creates higher-quality two-dimensional graphics, images, and text • Includes fill patterns such as gradients • Strokes that define the width and style of a drawing stroke • Anti-aliasing, a graphics technique for producing smoother on-screen graphics

26. Specifying the Rendering Attributes • Fill patterns- Control how a drawing will be filled in • Gradient fill- A gradual shift of color • Acyclic- color shift occurs once • Cyclic- color shift occurs repeatedly • setStroke()- Changes the width of the drawing line

27. Adding Sound, Images, and Simple Animation to Swing Applets • Java 2 supports sound • Use the play() method to retrieve and play sound • play() with one argument- the argument is a URL • play() with two arguments- loads and plays the audio file

28. Adding Sound, Images, and Simple Animation to Swing Applets • Images formats supported by Java include: • Graphics Interchange Format (GIF) • Maximum of 256 colors • Join Photographic Experts Group (JPEG) • Stores mostly photographs • Portable Network Graphics (PNG) • Stores images in a lossless form