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Message-ID:  <[log in to unmask]>
Date:         Thu, 14 Nov 2002 17:57:39 -0500
Reply-To:     ImageJ Interest Group <[log in to unmask]>
Sender:       ImageJ Interest Group <[log in to unmask]>
From:         Wayne Rasband <[log in to unmask]>
Subject:      Re: Color correction
In-Reply-To:  <[log in to unmask]>

> I *know* this should be a fairly simple plugin to write, but I don't
> know
> Java!  (I'm a non-GUI embedded C type, myself).  I'm sure I can pick
> up the
> small amount of Java I'll need to write the calculations and create a
> plugin
> (cut-&-paste), but I have no clue about building the GUI I'll need.
>
> How much of this can (or should) be implemented as a script?  How much
> should be implemented in Java (preferred) or in C (for speed)?  How
> much is
> already implemented in existing code?

This should be a plugin. Macros that do pixel-by-pixel processing are
about 100 times slower than plugins. There is no need for C. Java will
be plenty fast.

One way to have the user edit a 3x3 matrix is to display it in a
GenericDialog as a text area. This is what the Process>Filters>Convolve
command does for n x n kernels. A big advantage of using a
GenericDialog is it makes the plugin recordable so it can be called
from macros. I have attached an example plugin that allows a 3x3 matrix
to be edited.

-wayne

/************************** Color_Corrector.java
********************************/
import ij.*;
import ij.process.*;
import ij.gui.*;
import java.awt.*;
import ij.plugin.filter.*;
import java.util.*;

public class Color_Corrector implements PlugInFilter {
     ImagePlus imp;
     static double[] matrix =  {1.791,-0.517,-0.274,-0.090,
1.321,-0.231,-0.054,-0.236, 1.290};

     public int setup(String arg, ImagePlus imp) {
         this.imp = imp;
         return DOES_RGB;
     }

     public void run(ImageProcessor ip) {
         if (!getMatrix())
             return;
         displayMatrix();
     }

     boolean getMatrix() {
         GenericDialog gd = new GenericDialog("Matrix");
         String text = "";
         for (int i=0; i<9; i++) {
             text += IJ.d2s(matrix[i],3)+"  ";
             if (i%3==2)
                 text += "\n";
         }
         gd.addTextAreas(text, null, 5, 20);
         gd.showDialog();
         if (gd.wasCanceled())
             return false;
         text  = gd.getNextText();
         StringTokenizer st = new StringTokenizer(text);
         int n = st.countTokens();
         if (n!=9)
             {IJ.error("Matrix must be 3x3"); return false;}
         for (int i=0; i<9; i++)
             matrix[i] = getNum(st);
         return true;
     }

     double getNum(StringTokenizer st) {
         Double d;
         String token = st.nextToken();
         try {d = new Double(token);}
         catch (NumberFormatException e){d = null;}
         if (d!=null)
             return(d.doubleValue());
         else
             return 0.0;
      }

    void displayMatrix() {
         IJ.log("");
         IJ.log(matrix[0]+" "+matrix[1]+" "+matrix[2]);
         IJ.log(matrix[3]+" "+matrix[4]+" "+matrix[5]);
         IJ.log(matrix[6]+" "+matrix[7]+" "+matrix[8]);
    }

}

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