Image border problem using JAI

Question

I've written some very simple code to scale an image down to a small
thumbnail in JPG format but the quality is quite horrible. Is there a way of making it look nicer?
src = JAI.create("fileload","filepath")
ParameterBlock params = new ParameterBlock();
params.addSource(src);
params.add(xScale);//x scale factor
params.add(yScale);//y scale factor
params.add(0.0F);//x translate
params.add(0.0F);//y translate
params.add(Interpolation.getInstance(Interpolation.INTERP_NEAREST));
dest = JAI.create("scale", params,null);
I switched to InterpolationBicubic, instead of Interpolationnearest the quality was much better but the resulting image contained borders.
could some one tell me is there any other way to get better and nicer results.

Answer 1

Yes you can fix the border problem by setting a render hint to change the way the borders are handled. Something like the following will do the trick.
You can also use BORDER_WRAP instead of BORDER_COPY, both seem to have a similar result. Mind you I am still very dissapointed with the quality of the bicubic resampling in JAI, but at least this will fix the problem with the borders.
RenderingHints rh = new RenderingHints(JAI.KEY_BORDER_EXTENDER, BorderExtender.createInstance(BorderExtender.BORDER_COPY));
dest = JAI.create("scale", params,rh);