/*
* Copyright 2009 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.multi;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.NotFoundException;
import com.google.zxing.Reader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.ResultPoint;
import java.util.Hashtable;
import java.util.Vector;
/**
*
Attempts to locate multiple barcodes in an image by repeatedly decoding portion of the image.
* After one barcode is found, the areas left, above, right and below the barcode's
* {@link com.google.zxing.ResultPoint}s are scanned, recursively.
*
* A caller may want to also employ {@link ByQuadrantReader} when attempting to find multiple
* 2D barcodes, like QR Codes, in an image, where the presence of multiple barcodes might prevent
* detecting any one of them.
*
* That is, instead of passing a {@link Reader} a caller might pass
* new ByQuadrantReader(reader)
.
*
* @author Sean Owen
*/
public final class GenericMultipleBarcodeReader implements MultipleBarcodeReader {
private static final int MIN_DIMENSION_TO_RECUR = 30;
private final Reader delegate;
public GenericMultipleBarcodeReader(Reader delegate) {
this.delegate = delegate;
}
public Result[] decodeMultiple(BinaryBitmap image) throws NotFoundException {
return decodeMultiple(image, null);
}
public Result[] decodeMultiple(BinaryBitmap image, Hashtable hints)
throws NotFoundException {
Vector results = new Vector();
doDecodeMultiple(image, hints, results, 0, 0);
if (results.isEmpty()) {
throw NotFoundException.getNotFoundInstance();
}
int numResults = results.size();
Result[] resultArray = new Result[numResults];
for (int i = 0; i < numResults; i++) {
resultArray[i] = (Result) results.elementAt(i);
}
return resultArray;
}
private void doDecodeMultiple(BinaryBitmap image,
Hashtable hints,
Vector results,
int xOffset,
int yOffset) {
Result result;
try {
result = delegate.decode(image, hints);
} catch (ReaderException re) {
return;
}
boolean alreadyFound = false;
for (int i = 0; i < results.size(); i++) {
Result existingResult = (Result) results.elementAt(i);
if (existingResult.getText().equals(result.getText())) {
alreadyFound = true;
break;
}
}
if (alreadyFound) {
return;
}
results.addElement(translateResultPoints(result, xOffset, yOffset));
ResultPoint[] resultPoints = result.getResultPoints();
if (resultPoints == null || resultPoints.length == 0) {
return;
}
int width = image.getWidth();
int height = image.getHeight();
float minX = width;
float minY = height;
float maxX = 0.0f;
float maxY = 0.0f;
for (int i = 0; i < resultPoints.length; i++) {
ResultPoint point = resultPoints[i];
float x = point.getX();
float y = point.getY();
if (x < minX) {
minX = x;
}
if (y < minY) {
minY = y;
}
if (x > maxX) {
maxX = x;
}
if (y > maxY) {
maxY = y;
}
}
// Decode left of barcode
if (minX > MIN_DIMENSION_TO_RECUR) {
doDecodeMultiple(image.crop(0, 0, (int) minX, height),
hints, results, xOffset, yOffset);
}
// Decode above barcode
if (minY > MIN_DIMENSION_TO_RECUR) {
doDecodeMultiple(image.crop(0, 0, width, (int) minY),
hints, results, xOffset, yOffset);
}
// Decode right of barcode
if (maxX < width - MIN_DIMENSION_TO_RECUR) {
doDecodeMultiple(image.crop((int) maxX, 0, width - (int) maxX, height),
hints, results, xOffset + (int) maxX, yOffset);
}
// Decode below barcode
if (maxY < height - MIN_DIMENSION_TO_RECUR) {
doDecodeMultiple(image.crop(0, (int) maxY, width, height - (int) maxY),
hints, results, xOffset, yOffset + (int) maxY);
}
}
private static Result translateResultPoints(Result result, int xOffset, int yOffset) {
ResultPoint[] oldResultPoints = result.getResultPoints();
ResultPoint[] newResultPoints = new ResultPoint[oldResultPoints.length];
for (int i = 0; i < oldResultPoints.length; i++) {
ResultPoint oldPoint = oldResultPoints[i];
newResultPoints[i] = new ResultPoint(oldPoint.getX() + xOffset, oldPoint.getY() + yOffset);
}
return new Result(result.getText(), result.getRawBytes(), newResultPoints,
result.getBarcodeFormat());
}
}