scale image

[bubuzzz]

hi all,
i ve been trying to scale an image using java. The program runs well, however i found that the quality of the new image is not good, many rectangles appear in the image, especially when the dimensions of the new image are small (around 72 x 72 pixels).

This is my code:

public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		 BufferedImage bsrc;
		try {
		
		   bsrc = ImageIO.read(new File("/home/bubuzzz/Tools/Icon/ksirc.png"));
		   Image desc = bsrc.getScaledInstance(72, -1, Image.SCALE_SMOOTH);
		   BufferedImage bdest = toBufferedImage(desc);   
		   ImageIO.write(bdest,"PNG",new File("/home/bubuzzz/Desktop/ksirc.png"));
		   
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	public static BufferedImage toBufferedImage(Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage)image;
        }
    
        // This code ensures that all the pixels in the image are loaded
        image = new ImageIcon(image).getImage();
    
        // Determine if the image has transparent pixels; for this method's
        // implementation, see e661 Determining If an Image Has Transparent Pixels
        boolean hasAlpha = hasAlpha(image);
    
        // Create a buffered image with a format that's compatible with the screen
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        try {
            // Determine the type of transparency of the new buffered image
            int transparency = Transparency.OPAQUE;
            if (hasAlpha) {
                transparency = Transparency.BITMASK;
            }
    
            // Create the buffered image
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(
                image.getWidth(null), image.getHeight(null), transparency);
        } catch (HeadlessException e) {
            // The system does not have a screen
        }
    
        if (bimage == null) {
            // Create a buffered image using the default color model
            int type = BufferedImage.TYPE_INT_RGB;
            if (hasAlpha) {
                type = BufferedImage.TYPE_INT_ARGB;
            }
            bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        }
    
        // Copy image to buffered image
        Graphics g = bimage.createGraphics();
    
        // Paint the image onto the buffered image
        g.drawImage(image, 0, 0, null);
        g.dispose();
    
        return bimage;
    }
	
	public static boolean hasAlpha(Image image) {
        // If buffered image, the color model is readily available
        if (image instanceof BufferedImage) {
            BufferedImage bimage = (BufferedImage)image;
            return bimage.getColorModel().hasAlpha();
        }
    
        // Use a pixel grabber to retrieve the image's color model;
        // grabbing a single pixel is usually sufficient
         PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);
        try {
            pg.grabPixels();
        } catch (InterruptedException e) {
        }
    
        // Get the image's color model
        ColorModel cm = pg.getColorModel();
        return cm.hasAlpha();
    }

can you suggest any better way to scale the image? Thanks

[qwertino]

You have to blur the image before resizing:

see this page: componenthouse.com/article-20

[essimage]

Here is a Visual basic function that allow you to scale a image
also you can see from the example that at 300% increase there is little pixelation, if you use a blur function after you should not see any pixelation
ess-image.com/Graphic/Image_Processing/ZoomImage.aspx

I hope this helps you

[Turk4n]

Here is a Visual basic function that allow you to scale a image
also you can see from the example that at 300% increase there is little pixelation, if you use a blur function after you should not see any pixelation
ess-image.com/Graphic/Image_Processing/ZoomImage.aspx

I hope this helps you

To butt in, the function is good however it's hard to apply it as java code...
Try to help people in the way java was meant for