001/** 002 * Copyright (c) 2011, The University of Southampton and the individual contributors. 003 * All rights reserved. 004 * 005 * Redistribution and use in source and binary forms, with or without modification, 006 * are permitted provided that the following conditions are met: 007 * 008 * * Redistributions of source code must retain the above copyright notice, 009 * this list of conditions and the following disclaimer. 010 * 011 * * Redistributions in binary form must reproduce the above copyright notice, 012 * this list of conditions and the following disclaimer in the documentation 013 * and/or other materials provided with the distribution. 014 * 015 * * Neither the name of the University of Southampton nor the names of its 016 * contributors may be used to endorse or promote products derived from this 017 * software without specific prior written permission. 018 * 019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR 023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 029 */ 030package org.openimaj.demos.touchtable; 031 032import java.util.ArrayList; 033import java.util.Collection; 034import java.util.List; 035 036import org.openimaj.math.geometry.line.Line2d; 037import org.openimaj.math.geometry.point.Point2dImpl; 038import org.openimaj.math.geometry.shape.Circle; 039 040public class ReallyBasicTouchTracker { 041 private static final long TIME_TO_DIE = 500; 042 private long currentId = 0; 043 private List<Touch> lastPoints = new ArrayList<Touch>(); 044 private double threshold; 045 046 public ReallyBasicTouchTracker(double threshold) { 047 this.threshold = threshold; 048 } 049 050 public List<Touch> trackPoints(Collection<Touch> pts) { 051 List<Touch> newPoints = new ArrayList<Touch>(pts.size()); 052 for (Touch pt : pts) { 053 Touch matched = matchPoint(pt); 054 055 if (matched == null) { 056 newPoints.add(new Touch(pt, currentId++, null)); 057 } else { 058 059 lastPoints.remove(matched); 060 061 Point2dImpl mv = new Point2dImpl(pt.calculateCentroid()); 062 mv.x -= matched.getX(); 063 mv.y -= matched.getY(); 064 065 newPoints.add(new Touch(pt, matched.touchID, mv)); 066 } 067 } 068 for (Touch touch : lastPoints) { 069 if(System.currentTimeMillis() - touch.createdTime < TIME_TO_DIE){ 070 newPoints.add(touch); 071 } 072 } 073 lastPoints = newPoints; 074 075 return lastPoints; 076 } 077 078 private Touch matchPoint(Circle query) { 079 double minDist = Double.MAX_VALUE; 080 Touch best = null; 081 082 for (Touch pt : lastPoints) { 083 double dist = Line2d.distance(query.calculateCentroid(), pt.calculateCentroid()); 084 085 if (dist < minDist) { 086 minDist = dist; 087 best = pt; 088 } 089 } 090 091 if (minDist > threshold) 092 return null; 093 if(System.currentTimeMillis() - best.createdTime > TIME_TO_DIE){ 094 best=null; 095 } 096 return best; 097 } 098}