Noticed something funny today - well, it would be funny, except I've
already wasted several hours on it.
Once upon a time, I was able to arbitrarily scale my Images when I
painted them with Graphics.drawImage(image, x, y, width, height,
observer). Now I'm finding that isn't so.
The little snippet below illustrates this. It takes three arguments: an
image file name, a width and a height. Image not incuded, I'm afraid. I
recommend the following:
$ javac ImageScaling.java
$ file someimage.gif
someimage.gif: GIF image data, version 89a, 400 x 400,
$ java ImageScaling someimage.gif 400 400
i.e., compile and try it with the normal image size arguments to prove
it works normally. Then try shrinking it:
$ java ImageScaling someimage.gif 200 200
$ java ImageScaling someimage.gif 100 100
$ java ImageScaling someimage.gif 50 50
$ java ImageScaling someimage.gif 25 25
This should all work; at least it did for me.
Now try blowing it up:
$ java ImageScaling someimage.gif 800 800
$ java ImageScaling someimage.gif 1600 1600
For some reason, this doesn't work in general - the image isn't drawn at
all. I've had no success even just doubling both width and height.
Smaller images do seem to take longer to blow up, but I can't get
800x800 out of a 100x100 image.
I've ran back to 1.1.6, but my 1.1.5 and earlier were all libc5 and
don't work any more. This runs the same on all 1.1.6 as far as I can
tell.
So am I insane, or is this some new bug? The feature that depends on
this was working in our last version of our product; I just rewrote it
for swing and was reimplementing the feature under swing when I ran into
this all of a sudden. At first I thought it was Swing-related, but as
you can see I was able to demonstrate it using only AWT components.
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import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Frame;
public class ImageScaling extends Canvas {
private Image image;
private int width, height;
public static void main(String[] argv) {
String imagename = argv[0];
int width = (new Integer(argv[1])).intValue();
int height = (new Integer(argv[2])).intValue();
ImageScaling scaler = new ImageScaling(imagename, width, height);
Frame framed = new Frame("Image Scaling example");
framed.add(scaler, "Center");
framed.setSize(640, 480);
framed.show();
}
public ImageScaling(String imagename, int width, int height) {
image = getToolkit().getImage(imagename);
this.width = width;
this.height = height;
}
public void paint(Graphics g) {
g.drawImage(image, 0, 0, width, height, this);
}
}
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--
Paul Reavis [EMAIL PROTECTED]
Design Lead
Partner Software, Inc. http://www.partnersoft.com
