Displaying Images
/*
This applet will display a gif on screen
for now the gif file must be in the same directory
as this applet
*/
import java.awt.*;
import java.applet.*;
// These classes are for Url's.
import java.net.*;
public class ImageExample extends Applet
{
// Your image name;
Image
my_gif;
// The applet base URL
URL base;
// This object will allow you to control
loading
MediaTracker mt;
public
void init()
{
// initialize the MediaTracker
mt = new MediaTracker(this);
// The try-catch is necessary when the
URL isn't valid
// Of course this one is valid, since it
is generated by
// Java itself.
try {
// getDocumentbase gets the applet
path.
base = getDocumentBase();
}
catch (Exception e) {}
// Here we load the image.
// Only Gif and JPG are allowed. Transparent
gif also.
my_gif = getImage(base,"imageExample.gif");
// tell the MediaTracker to keep an eye
on this image, and give it ID 1;
mt.addImage(my_gif,1);
// now tell the mediaTracker to stop the
applet execution
// (in this example don't paint) until
the images are fully loaded.
// must be in a try catch block.
try {
mt.waitForAll();
}
catch (InterruptedException e) {}
// when the applet gets here then the
images is loaded.
}
public
void paint(Graphics g)
{
// now we are going to draw the gif on
the screen
// (image name,x,y,observer);
g.drawImage(my_gif,20,20,this);
// you can resize the image easily
g.drawImage(my_gif,20,140,30,40,this);
}
}
// That's all. Images can also be drawn without
the mediaTracker but then
// the screen will flicker.
// a base URL variable is also not necessary
but when you have lots of images to load
// then it's shorter to type.
// Next is the basic GUI (Graphical User Interface)
components.
Next...
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