I want to load an image without the extra white pixels. How do I do this?

Question

When i draw in image on a canvas, the white pixels surrounding the image are there too to the image boundries. Any tips on how to prevent this?

You need to draw a transparent image: http://stackoverflow.com/questions/8272583/drawing-transparent-images-in-java-graphics2d — zebediah49, Dec 17 '12 at 04:53
If the image isn't transparent to begin with, you can filter it so that the white pixels become transparent, but this will also occur with internal white pixels and so must be done with care. — Hovercraft Full Of Eels, Dec 17 '12 at 05:00
I don't have any internal white pixels, so how do I filter it? — Tikitaco, Dec 17 '12 at 05:01

Andrew Thompson · Accepted Answer · 2012-12-17T11:55:53.287

enter image description here

import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.imageio.ImageIO;
import java.net.URL;

class ImageTransparencyByColor {

    public static BufferedImage getTransparentImage(
        BufferedImage image, Color transparent) {
        // must have a transparent image
        BufferedImage img = new BufferedImage(
            image.getWidth(),image.getHeight(),BufferedImage.TYPE_INT_ARGB);
        Graphics2D g= img.createGraphics();
        for (int x=0; x<img.getWidth(); x++) {
            for (int y=0; y<img.getHeight(); y++) {
                if (image.getRGB(x,y)!=transparent.getRGB()) {
                    img.setRGB( x,y, image.getRGB(x,y) );
                }
            }
        }
        g.dispose();
        return img;
    }

    public static void main(String[] args) throws Exception {
        URL url = new URL ("http://www.gravatar.com/avatar" +
            "/ab5193916ccf152f96b0a69323e934a1?s=128&d=identicon&r=PG");
        final BufferedImage trans = getTransparentImage(
            ImageIO.read(url), Color.WHITE);
        Runnable r = new Runnable() {
            @Override
            public void run() {
                JLabel gui = new JLabel(new ImageIcon(trans));
                JOptionPane.showMessageDialog(null, gui);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

score 0 · Answer 2 · answered Dec 17 '12 at 04:55

0

Use a .png image. A .gif image has only total/no transpancy.

answered Dec 17 '12 at 04:55

underscore

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Michael 'Maik' Ardan · Answer 3 · 2012-12-17T07:16:48.990

Insert your image on a JPanel instead. Canvas is a heavyweight component. Alternatively, try to change alpha of your Canvas. this.setBackground(new Color( 0,0,0,0 );

EDIT: Try this. Create a class for your image. The way you initialize your Image doesn't matter.

public class MyImage extends JPanel {

    private final URL IMG_DIRECTORY = Main.class.getResource("/res/yourImage.png"); // Image directory

    public MyImage() {

        try {
            img = ImageIO.read(IMG_DIRECTORY);
        } catch (Exception e) {
            e.printStackTrace();
        }

        this.setSize(img.getWidth(null), img.getHeight(null);

    }

    @Override
    public void paint(Graphics g) {

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

    }

On your Frame class, declare your image class MyImage yourImage = new MyImage();, then add it to whatever your ContentPane was.

If any of my 2 answer didn't help you, please post your SSCCE — Michael 'Maik' Ardan, Dec 17 '12 at 05:21
The picture im loading is being overlayed over a series of different colored backgrounds, so i would need to the white pixels to be transparent somehow... — Tikitaco, Dec 17 '12 at 07:04

I want to load an image without the extra white pixels. How do I do this?

3 Answers3

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