Resizer.java

package ij.plugin.filter;
import ij.*;
import ij.gui.*;
import ij.process.*;
import ij.measure.*;
import java.awt.*;

public class Resizer implements PlugInFilter {
    ImagePlus imp;
    private boolean crop;
    private static int newWidth = 100;
    private static int newHeight = 100;
    private static boolean constrain = true;
    private static boolean interpolate = true;

    public int setup(String arg, ImagePlus imp) {
        crop = arg.equals("crop");
        this.imp = imp;
        IJ.register(Resizer.class);
        if (crop)
            return DOES_ALL+ROI_REQUIRED+NO_CHANGES;
        else
            return DOES_ALL+NO_CHANGES;
    }

    public void run(ImageProcessor ip) {
        Roi roi = imp.getRoi();
        if (roi!=null && roi.getType()>=Roi.LINE && roi.getType()<=Roi.FREELINE) {
            IJ.error("The Crop and Adjust->Size commands\ndo not work with line selections.");
            return;
        }
        boolean sizeToHeight=false;
        if (crop) {
            Rectangle bounds = roi.getBounds();
            newWidth = bounds.width;
            newHeight = bounds.height;
            interpolate = false;
        } else {
            GenericDialog gd = new GenericDialog("Resize", IJ.getInstance());
            gd.addNumericField("Width (pixels):", newWidth, 0);
            gd.addNumericField("Height (pixels):", newHeight, 0);
            gd.addCheckbox("Constrain Aspect Ratio", constrain);
            gd.addCheckbox("Interpolate", interpolate);
            gd.addMessage("NOTE: Undo is not available");
            gd.showDialog();
            if (gd.wasCanceled())
                return;
            newWidth = (int)gd.getNextNumber();
            newHeight = (int)gd.getNextNumber();
            if (gd.invalidNumber()) {
                IJ.error("Width or height are invalid.");
                return;
            }
            constrain = gd.getNextBoolean();
            interpolate = gd.getNextBoolean();
            sizeToHeight = constrain && newWidth==0;
            if (newWidth<=0.0 && !constrain)  newWidth = 50;
            if (newHeight<=0.0) newHeight = 50;
        }
        
        Rectangle r = ip.getRoi();
        double oldWidth = r.width;;
        double oldHeight = r.height;
        if (!crop && constrain) {
            if (sizeToHeight)
                newWidth = (int)(newHeight*(oldWidth/oldHeight));
            else
                newHeight = (int)(newWidth*(oldHeight/oldWidth));
        }
        ip.setInterpolate(interpolate);
        
        try {
            ip = ip.resize(newWidth, newHeight);
            ImagePlus imp2 = new ImagePlus(imp.getTitle(), ip);
            imp2.show();

        } catch(OutOfMemoryError o) {
            IJ.outOfMemory("Resize");
        }
    }

}