Convolving an image with a boxcar kernel in jython for Fiji - plugins

Question

I am trying to do some image processing in Fiji using jython and have run in to trouble. I am trying to develop a plugin where an image is convolved by a boxcar kernel. By recording a macro I get the following which could be pasted into the jython script:
run("Convolve...", "text1=[0.04 0.04 0.04 0.04 0.04\n0.04 0.04 0.04 0.04 0.04\n0.04 0.04 0.04 0.04 0.04\n0.04 0.04 0.04 0.04 0.04\n0.04 0.04 0.04 0.04 0.04\n]");
where text1 is the string used for the convolution. However, the problem is that the plugin requires that the user may define the size of the boxcar kernel. Thus, I cannot hardcode this into the script. Does anyone know how to proceed. I am open to alternative methods as long as the final result is a boxcar convolution.
Thank you very much in advance

Answer 1

You can construct the string that represents the kernel dynamically in jython for a given size and pass it as a parameter to imagej.
args=split(getArgument);
kernel = args[0];
run("Convolve...", "text1=&kernel");
Alternatively, pass size as a parameter and construct the string using the imagej macro language itself.
args=split(getArgument);
size = args[0];
// for loop to create kernel
run("Convolve...", "text1=&kernel");

Answer 2

Years later, but for posterity:
Looking at the ImageJ API, you can actually call the Convolver() class with the necessary arguments.
For example:
from ij import IJ
from ij import ImagePlus
from ij.plugin.filter import Convolver
imp = IJ.openImage("http://imagej.nih.gov/ij/images/blobs.gif")
ip = imp.getProcessor()
kernel = [1.0, 2.0, 1.0,
0.0, 0.0, 0.0,
-1.0, -2.0, -1.0]
Convolver().convolve(ip, kernel, 3, 3)
out = ImagePlus("convolved", ip)
out.show()
It should be arbitrary to ask the user for an input kernel list from there.