Direction indicator

Posted by Michael Doube on Sep 14, 2010; 8:50pm
URL: http://imagej.273.s1.nabble.com/Direction-indicator-tp3686815.html

Dear all,

I'm thinking about implementing a direction indicator to show the
orientation of the body that the image is from.  I mainly work with
anatomy, so the anatomical directions (medial, lateral, dorsal, ventral
etc.) are most interesting, but there's nothing stopping it from showing
compass directions (north, south, east, west) or anything else.

One way around this might be to rotate the image, but this would mean
interpolating pixels, which is bad.

My ideal would be to have a cross with text labels at the ends, that you
can move by grabbing the centre or rotate by grabbing the ends.  You
could also change the labels with a right click or a menu item
somewhere.  A bit like the zoom indicator but interactive.  It would
also have to exist without interference from ROIs or fiddling about with
the ROI Manager.

I had a go at doing this with Line and TextRoi, and the Overlay class
but only succeeded at showing the lines and text boxes; I couldn't grab
the handles and it behaves like an ROI by disappearing...

Any hints at how to achieve this better would be appreciated,

Michael

Abortive attempt follows...
---------------------------
package org.doube.geometry;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;

import ij.ImagePlus;
import ij.gui.Line;
import ij.gui.Overlay;
import ij.gui.Roi;
import ij.gui.TextRoi;

/**
  * Indicator to show anatomic directions such as medial, proximal, cranial
  *
  * Instantiate 2 line ROI's, lock their lengths, lock their midpoint to
always
  * be the same position.
  *
  * @author Michael Doube
  *
  */
@SuppressWarnings("serial")
public class AnatomicAxes {

        private static final String[][] axisLabels = { { "medial", "lateral" },
                        { "cranial", "caudal" }, { "rostral", "caudal" },
                        { "dorsal", "ventral" }, { "anterior", "posterior" },
                        { "superior", "inferior" }, { "proximal", "distal" },
                        { "dorsal", "palmar" }, { "dorsal", "plantar" },
                        { "dorsal", "volar" }, { "axial", "abaxial" } };

        /** Common midpoint */
        private int x, y;

        /** Axis length */
        private int length;
        private ImagePlus imp;
        private Line line1, line2;

        /** TextRoi labels for axes */
        private TextRoi tr1, tr2, tr3, tr4;

        private Graphics g;
        private Overlay overlay;

        public AnatomicAxes(ImagePlus imp) {
                this.imp = imp;
                int w = imp.getWidth();
                int h = imp.getHeight();
                this.length = Math.min(w, h) / 4;
                this.x = w / 2;
                this.y = h / 2;
                this.line1 = new Line(x, y - length, x, y + length);
                this.line2 = new Line(x - length, y, x + length, y);
                TextRoi.setFont("SansSerif", 10, Font.PLAIN, true);
                this.tr1 = new TextRoi(x, y - length - 10, axisLabels[0][0]);
                this.tr2 = new TextRoi(x, y + length + 10, axisLabels[0][1]);
                this.tr3 = new TextRoi(x - length - 10, y, axisLabels[1][0]);
                this.tr4 = new TextRoi(x + length + 10, y, axisLabels[1][1]);
                this.overlay = new Overlay();
                overlay.add(line1);
                overlay.add(line2);
                overlay.add(tr1);
                overlay.add(tr2);
                overlay.add(tr3);
                overlay.add(tr4);
                for (Roi r : overlay.toArray()){
                        r.setImage(this.imp);
                }
                overlay.setStrokeColor(new Color(0, 0, 255));
                this.imp.setOverlay(overlay);
                this.g = this.imp.getCanvas().getGraphics();
                create();
        }

        public void create() {
                for (Roi r : overlay.toArray())
                        r.draw(this.g);
        }

        public void reflect() {
                // TODO method stub
                // get whichever line is selected
                // swap the labels
        }

}