2 * Copyright 2007 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing;
19 import com.google.zxing.oned.MultiFormatOneDReader;
20 import com.google.zxing.qrcode.QRCodeReader;
21 import com.google.zxing.datamatrix.DataMatrixReader;
23 import java.util.Hashtable;
24 import java.util.Vector;
27 * MultiFormatReader is a convenience class and the main entry point into the library for most uses.
28 * By default it attempts to decode all barcode formats that the library supports. Optionally, you
29 * can provide a hints object to request different behavior, for example only decoding QR codes.
32 * @author dswitkin@google.com (Daniel Switkin)
34 public final class MultiFormatReader implements Reader {
36 private Hashtable hints;
37 private Vector readers;
40 * This version of decode honors the intent of Reader.decode(MonochromeBitmapSource) in that it
41 * passes null as a hint to the decoders. However, that makes it inefficient to call repeatedly.
42 * Use setHints() followed by decodeWithState() for continuous scan applications.
44 * @param image The pixel data to decode
45 * @return The contents of the image
46 * @throws ReaderException Any errors which occurred
48 public Result decode(MonochromeBitmapSource image) throws ReaderException {
50 return decodeInternal(image);
54 * Decode an image using the hints provided. Does not honor existing state.
56 * @param image The pixel data to decode
57 * @param hints The hints to use, clearing the previous state.
58 * @return The contents of the image
59 * @throws ReaderException Any errors which occurred
61 public Result decode(MonochromeBitmapSource image, Hashtable hints) throws ReaderException {
63 return decodeInternal(image);
67 * Decode an image using the state set up by calling setHints() previously. Continuous scan
68 * clients will get a <b>large</b> speed increase by using this instead of decode().
70 * @param image The pixel data to decode
71 * @return The contents of the image
72 * @throws ReaderException Any errors which occurred
74 public Result decodeWithState(MonochromeBitmapSource image) throws ReaderException {
75 // Make sure to set up the default state so we don't crash
76 if (readers == null) {
79 return decodeInternal(image);
83 * This method adds state to the MultiFormatReader. By setting the hints once, subsequent calls
84 * to decodeWithState(image) can reuse the same set of readers without reallocating memory. This
85 * is important for performance in continuous scan clients.
87 * @param hints The set of hints to use for subsequent calls to decode(image)
89 public void setHints(Hashtable hints) {
92 boolean tryHarder = hints != null && hints.containsKey(DecodeHintType.TRY_HARDER);
93 Vector possibleFormats = hints == null ? null : (Vector) hints.get(DecodeHintType.POSSIBLE_FORMATS);
94 readers = new Vector();
95 if (possibleFormats != null) {
96 boolean addOneDReader =
97 possibleFormats.contains(BarcodeFormat.UPC_A) ||
98 possibleFormats.contains(BarcodeFormat.UPC_E) ||
99 possibleFormats.contains(BarcodeFormat.EAN_13) ||
100 possibleFormats.contains(BarcodeFormat.EAN_8) ||
101 possibleFormats.contains(BarcodeFormat.CODE_39) ||
102 possibleFormats.contains(BarcodeFormat.CODE_128) ||
103 possibleFormats.contains(BarcodeFormat.ITF);
104 // Put 1D readers upfront in "normal" mode
105 if (addOneDReader && !tryHarder) {
106 readers.addElement(new MultiFormatOneDReader(hints));
108 if (possibleFormats.contains(BarcodeFormat.QR_CODE)) {
109 readers.addElement(new QRCodeReader());
111 if (possibleFormats.contains(BarcodeFormat.DATAMATRIX)) {
112 readers.addElement(new DataMatrixReader());
114 // At end in "try harder" mode
115 if (addOneDReader && tryHarder) {
116 readers.addElement(new MultiFormatOneDReader(hints));
119 if (readers.isEmpty()) {
121 readers.addElement(new MultiFormatOneDReader(hints));
123 readers.addElement(new QRCodeReader());
124 // TODO re-enable once Data Matrix is ready
125 // readers.addElement(new DataMatrixReader());
127 readers.addElement(new MultiFormatOneDReader(hints));
132 private Result decodeInternal(MonochromeBitmapSource image) throws ReaderException {
133 int size = readers.size();
134 for (int i = 0; i < size; i++) {
135 Reader reader = (Reader) readers.elementAt(i);
137 return reader.decode(image, hints);
138 } catch (ReaderException re) {
143 throw ReaderException.getInstance();