public int compare(ResultPointsAndTransitions resultpointsandtransitions, ResultPointsAndTransitions resultpointsandtransitions1)
{
return resultpointsandtransitions.getTransitions() - resultpointsandtransitions1.getTransitions();
}
/**
* Detects a Data Matrix Code in an image.
*
* @return {@link DetectorResult} encapsulating results of detecting a Data Matrix Code
* @throws NotFoundException if no Data Matrix Code can be found
*/
public DetectorResult detect() throws NotFoundException {
ResultPoint[] cornerPoints = rectangleDetector.detect();
ResultPoint pointA = cornerPoints[0];
ResultPoint pointB = cornerPoints[1];
ResultPoint pointC = cornerPoints[2];
ResultPoint pointD = cornerPoints[3];
// Point A and D are across the diagonal from one another,
// as are B and C. Figure out which are the solid black lines
// by counting transitions
Vector transitions = new Vector(4);
transitions.addElement(transitionsBetween(pointA, pointB));
transitions.addElement(transitionsBetween(pointA, pointC));
transitions.addElement(transitionsBetween(pointB, pointD));
transitions.addElement(transitionsBetween(pointC, pointD));
Collections.insertionSort(transitions, new ResultPointsAndTransitionsComparator());
// Sort by number of transitions. First two will be the two solid sides; last two
// will be the two alternating black/white sides
ResultPointsAndTransitions lSideOne = (ResultPointsAndTransitions) transitions.elementAt(0);
ResultPointsAndTransitions lSideTwo = (ResultPointsAndTransitions) transitions.elementAt(1);
// Figure out which point is their intersection by tallying up the number of times we see the
// endpoints in the four endpoints. One will show up twice.
Hashtable pointCount = new Hashtable();
increment(pointCount, lSideOne.getFrom());
increment(pointCount, lSideOne.getTo());
increment(pointCount, lSideTwo.getFrom());
increment(pointCount, lSideTwo.getTo());
ResultPoint maybeTopLeft = null;
ResultPoint bottomLeft = null;
ResultPoint maybeBottomRight = null;
Enumeration points = pointCount.keys();
while (points.hasMoreElements()) {
ResultPoint point = (ResultPoint) points.nextElement();
Integer value = (Integer) pointCount.get(point);
if (value.intValue() == 2) {
bottomLeft = point; // this is definitely the bottom left, then -- end of two L sides
} else {
// Otherwise it's either top left or bottom right -- just assign the two arbitrarily now
if (maybeTopLeft == null) {
maybeTopLeft = point;
} else {
maybeBottomRight = point;
}
}
}
if (maybeTopLeft == null || bottomLeft == null || maybeBottomRight == null) {
throw NotFoundException.getNotFoundInstance();
}
// Bottom left is correct but top left and bottom right might be switched
ResultPoint[] corners = {maybeTopLeft, bottomLeft, maybeBottomRight};
// Use the dot product trick to sort them out
ResultPoint.orderBestPatterns(corners);
// Now we know which is which:
ResultPoint bottomRight = corners[0];
bottomLeft = corners[1];
ResultPoint topLeft = corners[2];
// Which point didn't we find in relation to the "L" sides? that's the top right corner
ResultPoint topRight;
if (!pointCount.containsKey(pointA)) {
topRight = pointA;
} else if (!pointCount.containsKey(pointB)) {
topRight = pointB;
} else if (!pointCount.containsKey(pointC)) {
topRight = pointC;
} else {
topRight = pointD;
}
// Next determine the dimension by tracing along the top or right side and counting black/white
// transitions. Since we start inside a black module, we should see a number of transitions
// equal to 1 less than the code dimension. Well, actually 2 less, because we are going to
// end on a black module:
// The top right point is actually the corner of a module, which is one of the two black modules
// adjacent to the white module at the top right. Tracing to that corner from either the top
// left
// or bottom right should work here.
int dimension =
Math.min(
transitionsBetween(topLeft, topRight).getTransitions(),
transitionsBetween(bottomRight, topRight).getTransitions());
if ((dimension & 0x01) == 1) {
// it can't be odd, so, round... up?
dimension++;
}
dimension += 2;
// correct top right point to match the white module
ResultPoint correctedTopRight =
correctTopRight(bottomLeft, bottomRight, topLeft, topRight, dimension);
if (correctedTopRight == null) {
correctedTopRight = topRight;
}
// We redetermine the dimension using the corrected top right point
int dimension2 =
Math.max(
transitionsBetween(topLeft, correctedTopRight).getTransitions(),
transitionsBetween(bottomRight, correctedTopRight).getTransitions());
dimension2++;
if ((dimension2 & 0x01) == 1) {
dimension2++;
}
BitMatrix bits =
sampleGrid(image, topLeft, bottomLeft, bottomRight, correctedTopRight, dimension2);
return new DetectorResult(
bits, new ResultPoint[] {topLeft, bottomLeft, bottomRight, correctedTopRight});
}