Implemented a class (and a unit test) that can quickly locate the nearest

coordinate-having object to a specified coordinate from a set of such objects. It does so using an efficient algorithm so that we can do things like highlight the object nearest the mouse cursor. git-svn-id: https://samskivert.googlecode.com/svn/trunk@516 6335cc39-0255-0410-8fd6-9bcaacd3b74c
2001-12-15 03:19:03 +00:00
parent 3ce9fa00c8
commit 2b69011649
2 changed files with 397 additions and 0 deletions
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+//
+// $Id: ProximityTrackerTest.java,v 1.1 2001/12/15 03:19:03 mdb Exp $
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001 Michael Bayne
+// 
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.swing.util;
+
+import java.awt.Point;
+import java.util.ArrayList;
+import java.util.Random;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+
+import com.samskivert.Log;
+import com.samskivert.util.StringUtil;
+
+public class ProximityTrackerTest extends TestCase
+{
+    public ProximityTrackerTest ()
+    {
+        super(ProximityTrackerTest.class.getName());
+    }
+
+    public void runTest ()
+    {
+        Random rand = new Random();
+        ProximityTracker tracker = new ProximityTracker();
+        ArrayList points = new ArrayList();
+
+        // create 100 random points and add them to the tracker and our
+        // comparison list
+        for (int i = 0; i < 100; i++) {
+            int x = rand.nextInt(MAX_X);
+            int y = rand.nextInt(MAX_Y);
+            Point p = new Point(x, y);
+            tracker.addObject(x, y, p);
+            points.add(p);
+        }
+
+        // now choose 100 new random points and confirm that the tracker
+        // reports the same closest point that our brute force check
+        // reports
+        for (int i = 0; i < 100; i++) {
+            int x = rand.nextInt(MAX_X);
+            int y = rand.nextInt(MAX_Y);
+
+            // get the closest point via the tracker
+            Point tp = (Point)tracker.findClosestObject(x, y, null);
+
+            // get the closest point via brute force
+            Point cp = null;
+            int mindist = Integer.MAX_VALUE;
+            for (int p = 0; p < points.size(); p++) {
+                Point hp = (Point)points.get(p);
+                int dist = ProximityTracker.distance(hp.x, hp.y, x, y);
+                if (dist < mindist) {
+                    mindist = dist;
+                    cp = hp;
+                }
+            }
+
+            // the points might actually be different, but in that case,
+            // the distances should be equal
+            int tdist = ProximityTracker.distance(x, y, tp.x, tp.y);
+            int cdist = ProximityTracker.distance(x, y, cp.x, cp.y);
+
+            String tps = tp.x + "," + tp.y;
+            String cps = cp.x + "," + cp.y;
+            String ps = x + "," + y;
+            assert(ps + " => " + cps + " (" + cdist + ") ! " +
+                   tps + " (" + tdist + ")", tp.equals(cp) || (tdist == cdist));
+        }
+    }
+
+    public static Test suite ()
+    {
+        return new ProximityTrackerTest();
+    }
+
+    public static void main (String[] args)
+    {
+        ProximityTrackerTest test = new ProximityTrackerTest();
+        test.runTest();
+    }
+
+    protected static final int MAX_X = 1000;
+    protected static final int MAX_Y = 1000;
+}