How to scale a BufferedImage

java image image-processing bufferedimage image-scaling
Thiago Diniz picture Thiago Diniz · Nov 18, 2010 · Viewed 109.4k times · Source

Following the javadocs, I have tried to scale a BufferedImage without success here is my code:

BufferedImage image = MatrixToImageWriter.getBufferedImage(encoded);
Graphics2D grph = image.createGraphics();
grph.scale(2.0, 2.0);
grph.dispose();

I can't understand why it is not working, any help?

Answer

trashgod picture trashgod · Nov 18, 2010

AffineTransformOp offers the additional flexibility of choosing the interpolation type.

BufferedImage before = getBufferedImage(encoded);
int w = before.getWidth();
int h = before.getHeight();
BufferedImage after = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
AffineTransform at = new AffineTransform();
at.scale(2.0, 2.0);
AffineTransformOp scaleOp = 
   new AffineTransformOp(at, AffineTransformOp.TYPE_BILINEAR);
after = scaleOp.filter(before, after);

The fragment shown illustrates resampling, not cropping; this related answer addresses the issue; some related examples are examined here.

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