Quality loss when loading image into ImageIcon
Hi,
I have this piece of code that creates an ImageIcon to be set as Icon for a JLabel. The problem is that the image quality is reduced to multi-uglyness and I can't figure out how to add just the ImageIcon without loss of precision.
Thanks for your help !
Coenos
/**
* Gets the image Icon of a certain imageLocation
*
* @param imageLocation
* @param width
* @param height
* @return
*/
public static ImageIcon getImageIcon(String imageLocation, int width, int height) {
// create imageIcon
ImageIcon imageIcon = new ImageIcon(imageLocation);
Image image = imageIcon.getImage().getScaledInstance(
width, height, 0);
// scale image
imageIcon.setImage(image);
return imageIcon;
}
[814 byte] By [
Coenosiaa] at [2007-10-3 3:43:52]
getScaledInstance(width, height, 0)
There are five scaling algorithm flags ranging from 1 to 16 that can be used as hints in getScaledInstance. These are listed in the method detail for the method in the Image class api. Follow the link for one of them to the field detail and on to the Constant_Field_Values for Image to find the int values for each static constant.
If you want good quality you might try Image.SCALE_AREA_AVERAGING (16). This method works well for scaling to smaller size and is slow. If you are scaling up or want more speed you can try working with BufferedImage, AffineTransform scale instance and the Graphics2D rendering hint value RenderingHints.VALUE_INTERPOLATION_BICUBIC.
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.*;
import javax.imageio.ImageIO;
import javax.swing.*;
public class QuickScale
{
private JPanel getContent(BufferedImage image)
{
JPanel panel = new JPanel(new GridLayout(1,0));
panel.add(new JLabel(new ImageIcon(image)));
BufferedImage scaled = getScaledImage(image, 175, 140);
panel.add(new JLabel(new ImageIcon(scaled)));
return panel;
}
private BufferedImage getScaledImage(BufferedImage src, int w, int h)
{
BufferedImage dest = new BufferedImage(w, h, src.getType());
Graphics2D g2 = dest.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BICUBIC);
// fill background for scale to fit
g2.setPaint(UIManager.getColor("Panel.background"));
g2.fillRect(0, 0, w, h);
double xScale = (double)w / src.getWidth();
double yScale = (double)h / src.getHeight();
double scale = Math.min(xScale, yScale);// scale to fit
//Math.max(xScale, yScale); // scale to fill
double x = (w - scale*src.getWidth())/2;
double y = (h - scale*src.getHeight())/2;
AffineTransform at = AffineTransform.getTranslateInstance(x, y);
at.scale(scale, scale);
g2.drawRenderedImage(src, at);
g2.dispose();
return dest;
}
public static void main(String[] args) throws IOException
{
File file = new File("images/cougar.jpg");
BufferedImage bi = ImageIO.read(file);
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new QuickScale().getContent(bi));
f.pack();
f.setLocation(200,200);
f.setVisible(true);
}
}
