Int32 support

[ExtraE113]

Fixes #15

[mkitti]

There is a IntProcessor in ImageJ1 now:
https://github.com/imagej/ImageJ/blob/84e9e3b0c872b5c38121d0e77b6fbd4cfa4a3b9b/ij/process/IntProcessor.java

Does this use that?

[ctrueden]

There is a IntProcessor in ImageJ1 now
Does this use that?

@mkitti No, it copies from int[] to float[].

But it could use IntProcessor for (signed) int32. Here is an example in Groovy:

import ij.process.IntProcessor
import ij.IJ
import ij.ImagePlus

size = 800;
n = size*size;
ip = new IntProcessor(size,size);
range = (long) (2 ** 32)
println(range)

for (var i=0; i<n; i++) {
  value = Integer.MIN_VALUE + (int) (i*range/n);
  if (i < 10) println(value);
  ip.set(i, value);
}
img = new ImagePlus("32-bit int image",ip);
img.getProcessor().resetMinAndMax();
IJ.run(img,"Viridis","");
img.show();