I'm using a library called Image4j to load an ico file, choose one of the images from the list, scale it (if necessary) and put it in a JLabel as an ImageIcon.
The library has a method read(File icoFile) which returns a List<BufferedImage> , a list of all the images contained within the ico file.
What I want to be able to do is quickly choose the image from the list that is the closest fit for the size of the label. Both the labels and the ico images will be square.
I've come up with the most naive way, but I suspect there's a faster one. I'd settle for this one, but my program will be doing this routine a lot so I want this part to be as efficient as possible.
public class IconUtil() {
private final List<BufferedImage> list;
public IconUtil(List<BufferedImage> list) {
this.list = list;
}
public BufferedImage getBestFit(int sizeToFit) {
int indexOfBestFit = 0; // assume it's the first image
int bestMargin = Math.abs(list.get(0).getWidth() - sizeToFit);
int margin;
for(int i = 1; i < list.size(); i++) {
margin = Math.abs(list.get(i).getWidth() - sizeToFit);
if(margin < bestMargin) {
bestMargin = margin;
indexOfBestFit = i;
}
}
return list[indexOfBestFit];
}
}
The choice to compare the images by their width was arbitrary because they're all square.
Also, as the main reason for picking the best fit is to try and maintain the quality of the images, should this method discard any images which are smaller than the target size? If so, how would that change the algorithm?
I have little experience with re-scaling images in Java. Is it even necessary to find the closest match in size? Maybe there are ways to re-scale without losing much quality even if the original is much bigger?
