Pixel graphics - An Introduction to Graphical User Interfaces with Java Swing - page 166

9.
10.

// Adjust the following path if necessary

11.

private static final String picturePath ="./its/TestData/orange.png";

12.

private MediaTracker mediTracker;

13.

private int imageID = 0;

14.
15.

public ImageScaleFrame() {

16.

this .setSize(800,600);

17.

ImagePanel ip = new ImagePanel();

18.

JScrollPane sp = new JScrollPane(ip);

19.

sp.setHorizontalScrollBarPolicy
(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

20.

sp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

21.

this .getContentPane().add(sp);

22. mediTracker = new MediaTracker( this );

23.
24.

Image original = loadImageAndTrack(picturePath);

25. ip.addImage(original);

26. Image klein = scaleImage(original,0.5);

27. ip.addImage(klein);

28. Image gross = scaleImage(original,2.0);

29. ip.addImage(gross);

30.

repaint();

31.

}

32.
33. private Image scaleImage(Image im, double factor){
34.

imageID++;

35.

int newWidth = ( int )(im.getWidth( this )*factor);

36.

int newHeight = ( int )(im.getWidth( this )*factor);

37.
38.

Image scaledIm =
im.getScaledInstance(newWidth,newHeight,Image.SCALE_FAST)

39.
40.

mediTracker.addImage(scaledIm,imageID);

41.

try {

42.

mediTracker.waitForID(imageID);

43. }

44. catch (Exception ex) {

45. ex.printStackTrace();

46. }

47. return (scaledIm);

48. }
49.
50. private Image loadImageAndTrack(String filename)
51.

{

52.

Image im = Toolkit.getDefaultToolkit().getImage(filename);

53.

imageID++;