Как изменить размер imageicon java

[icon][icon][icon][....]
where icon = jlabel and the user can add more icons

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Daniel Searson wrote:Ok, here’s one way of doing it.

You load your image straight into the ImageIcon using the constructor that takes a file name as an argument like:

ImageIcon icon = new ImageIcon(«whatever.jpg»);

Make sure the reference you create is an ImageIcon reference. Then use getImage() to grab the image from the ImageIcon:

Image img = icon.getImage();

Now create a buffered image the same size as the image:

BufferedImage bi = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_ARGB);

Then blit the icon image to the buffered image, and resize it as you do so:

Graphics g = bi.createGraphics();

g.drawImage(img, 0, 0, WIDTH, HEIGHT, null);

(The code above may be incorrect — check the docs)

Now recreate the IconImage with the new buffered image:

IconImage newIcon = new IconImage(bi);

Hope that helps.

— Daniel

I like this option. All of the posts I have read elsewhere recommend using the BufferedImage/Graphics.drawImage approach.

In this situation, it looks like you do actually need a resized image. In the project I am working on, I have been using a modified JLabel to use a resized icon. You may not need the whole IconLabel class, but it does implement the resize technique mentioned above. For added bonus (and for satisfying my OCD), I have pieced together some logic that also scales the image to within a certain size, maintaining its aspect ratio (i.e., I used http://stackoverflow.com/questions/10245220/java-image-resize-maintain-aspect-ratio). That way, you can pre-determine how big of a space you want your image to take without compromising its aspect ratio. The getScaledDimension is taken from that URL, and it does a better job of explaining how it resizes an image and maintains its aspect ratio.

In this JLabel-extending class, the real tricks are to override getPreferredSize and the paintComponent methods, where I do the image resizing.

Код: Выделить всё

		URL imageURL = getClass().getResource("/test.jpg");
		ImageIcon imageIcon = new ImageIcon(imageURL);
		Image image = imageIcon.getImage();
		ToolkitImage toolkitImage = (ToolkitImage)image;
		BufferedImage bufferedImage = toolkitImage.getBufferedImage();

Код: Выделить всё

	public static BufferedImage resizeImage(BufferedImage image, int width, int height) {
		
		ColorModel cm = image.getColorModel();
		
	    WritableRaster raster = cm.createCompatibleWritableRaster(width, height);
	    
	    boolean isRasterPremultiplied = cm.isAlphaPremultiplied();
	    
	    BufferedImage target = new BufferedImage(cm, raster, isRasterPremultiplied, null);
	    Graphics2D g2 = target.createGraphics();
	    g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
	    
	    double scalex = (double) target.getWidth()/ image.getWidth();
	    double scaley = (double) target.getHeight()/ image.getHeight();
	    
	    AffineTransform xform = AffineTransform.getScaleInstance(scalex, scaley);
	    g2.drawRenderedImage(image, xform);
	    g2.dispose();
	    return target;
	}

Код: Выделить всё

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.net.URL;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

import sun.awt.image.ToolkitImage;

public class ChangeIconSize {

	public ChangeIconSize() {
		
		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		JPanel panel = new JPanel();
		panel.setLayout(null);
		
		init(panel);
		
		frame.add(panel);
		
		frame.setSize(800, 600);
		frame.setVisible(true);
		
	}
	
	private void init(JPanel panel) {
				
		URL imageURL = getClass().getResource("/test.jpg");
		
		ImageIcon imageIcon = new ImageIcon(imageURL);
		
		JLabel l1 = new JLabel(imageIcon);
		l1.setBounds(0, 0, 400, 300);
		panel.add(l1);
		
		Image image = imageIcon.getImage();
		ToolkitImage toolkitImage = (ToolkitImage)image;
		BufferedImage bufferedImage = toolkitImage.getBufferedImage();		
		BufferedImage resizedImage = resizeImage(bufferedImage, bufferedImage.getWidth()/2, bufferedImage.getHeight()/2);
		
		ImageIcon imageIcon2 = new ImageIcon(resizedImage);
		
		JLabel l2 = new JLabel(imageIcon2);
		l2.setBounds(400, 0, 400, 300);
		panel.add(l2);
		
	}
	
	public static BufferedImage resizeImage(BufferedImage image, int width, int height) {
		
		ColorModel cm = image.getColorModel();
		
	    WritableRaster raster = cm.createCompatibleWritableRaster(width, height);
	    
	    boolean isRasterPremultiplied = cm.isAlphaPremultiplied();
	    
	    BufferedImage target = new BufferedImage(cm, raster, isRasterPremultiplied, null);
	    Graphics2D g2 = target.createGraphics();
	    g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
	    
	    double scalex = (double) target.getWidth()/ image.getWidth();
	    double scaley = (double) target.getHeight()/ image.getHeight();
	    
	    AffineTransform xform = AffineTransform.getScaleInstance(scalex, scaley);
	    g2.drawRenderedImage(image, xform);
	    g2.dispose();
	    return target;
	}
	
	public static void main(String[] args) {
		new ChangeIconSize();
	}

}

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