HandwritingRecognizer.java

package edu.stanford.hci.r3.events.handlers;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import edu.stanford.hci.r3.events.EventHandler;
import edu.stanford.hci.r3.events.PenEvent;
import edu.stanford.hci.r3.pen.PenSample;
import edu.stanford.hci.r3.pen.handwriting.HandwritingRecognitionService;
import edu.stanford.hci.r3.pen.ink.Ink;
import edu.stanford.hci.r3.pen.ink.InkStroke;
import edu.stanford.hci.r3.units.PatternDots;
import edu.stanford.hci.r3.units.Units;
import edu.stanford.hci.r3.units.coordinates.PercentageCoordinates;

public abstract class HandwritingRecognizer extends EventHandler {

        private static final PatternDots DOTS = new PatternDots();

        private List<PenSample> currentStrokeSamples = new ArrayList<PenSample>();

        private HandwritingRecognitionService recognizerService;

        private List<InkStroke> strokes = Collections.synchronizedList(new ArrayList<InkStroke>());

        public HandwritingRecognizer() {
                recognizerService = HandwritingRecognitionService.getInstance();
        }

        public void clear() {
                strokes.clear();
        }

        public abstract void contentArrived();

        public void handleEvent(PenEvent event) {
                final PercentageCoordinates percentageLocation = event.getPercentageLocation();
                final Units x = percentageLocation.getX();
                final Units y = percentageLocation.getY();
                final long timestamp = event.getTimestamp();

                // collect the ink strokes
                if (event.isTypePenDown()) {
                        // not a pen error!
                        currentStrokeSamples.clear();
                        currentStrokeSamples.add(new PenSample(x.getValueInPixels(), y.getValueInPixels(), 128,
                                        timestamp));
                } else if (event.isTypePenUp()) {
                        strokes.add(new InkStroke(currentStrokeSamples, DOTS));
                        contentArrived();
                        // System.out.println("Collected " + strokes.size() + " strokes so far.");
                } else { // regular sample
                        currentStrokeSamples.add(new PenSample(x.getValueInPixels(), y.getValueInPixels(), 128,
                                        timestamp));
                }
        }

        public String recognizeHandwriting() {
                if (strokes.size() == 0) {
                        // DebugUtils.println("Num Strokes to Recognize: " + strokes.size());
                        return "";
                } else {
                        final Ink ink = new Ink(strokes);
                        final String xml = ink.getAsXML(false /* no separator lines */);
                        final String result = recognizerService.recognizeHandwriting(xml);
                        return result;
                }
        }

        public List<String> recognizeHandwritingWithAlternatives() {
                recognizeHandwriting();
                return recognizerService.getAlternatives();
        }

        @Override
        public String toString() {
                return "Handwriting Recognizer: " + strokes.size() + " strokes.";
        }

}

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