Java Newbie with Errors Question

Hi All,

I have just started learning Java; so I don't know much and could really
use some help on this since I have spent hours and I'm not getting
anywhere. I had H.W. that wanted me to do a rotate filter on an image.
I thought it would be a switch of x,y. Well, the code compiles but I'm getting all
these errors when I try to apply it. What do all these errors mean?

Here's the code:

import java.awt.Color;

public class RotateFilter extends Filter
{

public RotateFilter(String name)
{
super(name);
      }
public void apply(OFImage image)
{
int height = image.getHeight();
int width = image.getWidth();
for(int y = 0; y < height; y++) {
for(int x = 0; x < width; x++) {
image.setPixel(y, x, image.getPixel(y, height-1-x));
}}}}

Here's part of the errors: They go on and on
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Coordinate out of bounds!
      at sun.awt.image.ByteInterleavedRaster.getDataElements(ByteInterleavedRaster.java:301)
      at java.awt.image.BufferedImage.getRGB(BufferedImage.java:871)
      at OFImage.getPixel(OFImage.java:54)
      at RotateFilter.apply(RotateFilter.java:33)
      at ImageViewer.applyFilter(ImageViewer.java:126)
      at ImageViewer.access$600(ImageViewer.java:22)

Thanks in advance for any help.

I think they probably mean you to extend ImageFilter. Here's an example:

http://www.enme.umd.edu/ESCML/Courseware/Rotate90DegreeFilter.java

> >>>>>>Here the problem height-1-x

can you post get pixel code

Has your image square shape - so that always width == height ?
If not then
as the first position corresponds to width, and your y corresponds to height,
so if your image is rectangular (not square) , then y in the fist position going up to height
will become higher than the limit of your image on the width if height > width, or
there wiil be similar problem on the second position if height < width.

I am also not sure you can manipulate all within one image - it is safer to create new image instance
with the same dimensions and assign pixels of image1 to image
and then replace the whole image.

Of course to extend ImageFilter as CEHJ suggested is probably the way the do such things

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you need to create a new image to copy the rotated pixels into (as the rotated image will not be the same size as the original image), similiar to what is done when resizing an image

Thank you to all of you for getting me back on track
with the extend Image Filter.

Thanks again for the help.

Java Newbie with Errors Question

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