Solutions to selected exercises - An Introduction to Graphical User Interfaces with Java Swing - page 288

15.

DirectionPanel dirPanel = new DirectionPanel(posModel, this );

16.

this .getContentPane().add(dirPanel,BorderLayout.SOUTH);

17.

}

18.
19. }

File: its/ResizeJumpDisplay/ResizeJumpPanel.java

1. package its.ResizeJumpDisplay;
2.
3. import java.awt.Color;
4. import java.awt.Graphics;
5. import javax.swing.JPanel;
6.
7. public class ResizeJumpPanel extends JPanel{
8.
9.
10. private PositionModel posModel;

11.
12.

public ResizeJumpPanel(PositionModel pm){

13. posModel = pm;

14. this .setBackground(Color.yellow);

15. }

16.
17.

public void paintComponent(Graphics g)

18.

{

19.

super .paintComponent(g);

20.

// get the current dimensions of the panel in pixels

21.

int currentWidth = this .getWidth();

22.

int currentHeight = this .getHeight();

23.
24. // compute the current size of a step in pixels

25.

int hStepInPixels = currentWidth/posModel.getNoOfSteps();

26.

int vStepInPixels = currentHeight/posModel.getNoOfSteps();

27.
28.

// compute the pixel positions of the

29.

// upper left corner of the black rectangle

30.

// and its width and height .

31.

int upperLeftX = posModel.getXInSteps() * hStepInPixels;

32. int upperLeftY = posModel.getYInSteps() * vStepInPixels;

33. int blackWidth = hStepInPixels * posModel.getBlackSizeInSteps();

34. int blackHeight= vStepInPixels * posModel.getBlackSizeInSteps();

35.
36.

// set colour to black

37. g.setColor(Color.black);

38.