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From: Martin Gregorie <martin@address-in-sig.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: Can you resize with BufferedImage
Date: Wed, 12 Apr 2017 10:18:49 -0000 (UTC)
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On Wed, 12 Apr 2017 10:34:04 +0200, Cecil Westerhof wrote:

> In my code I have the following code:
>     dest = image.getSubimage(x, y, dispWidth, dispHeight);
> 
> This is the part that I want to select, but I want to resize it at the
> same time. In this case I would like to scale to 50%.
> How should I do that?

Use an AffineTransform. 

The image resizing code should look something like this fragment:

   AffineTransform at = new AffineTransform();
   at.scale(scale, scale);
   AffineTransformOp op = new AffineTransformOp(at,
                              AffineTransformOp.TYPE_BICUBIC);
   Double nw = new Double(w * scale);
   Double nh = new Double(h * scale);
   om = new BufferedImage(nw.intValue(),
                          nh.intValue(),
                          BufferedImage.TYPE_3BYTE_BGR);
   op.filter(im, om);

where:
im    is a BufferedImage containing the old image
om    is a BufferedImage to hold the modified image
scale is a double containing the required scaling factor

I'm scaling images to a width of 400 pixels, so I calculate scale as 
400.0 / image_width. You would just set scale to 0.5. I want to keep the 
image proportion, so I use the same scale value for both width and height.


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
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