ImageFile: Detect barcodes using zxing

Use zxing to detect ultiple different types of barcodes including
1D and 2D. CODABAR, Code 128, DataMatrices, QR Codes, etc.
can be detected with a high degree of accuracy.

file_metadata/image/image_file.py

@@ -4,9 +4,11 @@
                         print_function)
 
 import os
+import re
 
 import cv2
 
+from file_metadata._compat import check_output, makedirs
 from file_metadata.generic_file import GenericFile
 from file_metadata.utilities import (app_dir, bz2_decompress, download,
                                      to_cstr, PropertyCached)
@@ -105,3 +107,54 @@ def tup2(pt1, pt2):
             data.append(fdata)
 
         return {'dlib:Faces': data}
+
+    def analyze_barcode(self):
+        """
+        Use ``zxing`` tot find barcodes, qr codes, data matrices, etc.
+        from the image.
+        """
+        # Make directory for data
+        path_data = app_dir('user_data_dir', 'zxing')
+        makedirs(path_data, exist_ok=True)
+
+        def download_jar(path, name, ver):
+            data = {'name': name, 'ver': ver, 'path': path}
+            fname = os.path.join(path_data, '{name}-{ver}.jar'.format(**data))
+            download('http://central.maven.org/maven2/{path}/{name}/{ver}/'
+                     '{name}-{ver}.jar'.format(**data),
+                     fname)
+            return fname
+
+        # Download all important jar files
+        path_core = download_jar('com/google/zxing', 'core', '3.2.1')
+        path_javase = download_jar('com/google/zxing', 'javase', '3.2.1')
+        path_jcomm = download_jar('com/beust', 'jcommander', '1.48')
+
+        output = check_output([
+            'java', '-cp', ':'.join([path_core, path_javase, path_jcomm]),
+            'com.google.zxing.client.j2se.CommandLineRunner', '--multi',
+            'file://{0}'.format(self.filename)])
+
+        if 'No barcode found' in output:
+            return {}
+
+        barcodes = []
+        for section in output.split("\nfile:"):
+            lines = section.strip().splitlines()
+
+            _format = re.search(r'format:\s([^,]+)', lines[0]).group(1)
+            raw_result = lines[2]
+            parsed_result = lines[4]
+            num_pts = int(re.search(r'Found (\d+) result points.', lines[5])
+                          .group(1))
+            points = []
+            float_re = r'(\d*[.])?\d+'
+            for i in range(num_pts):
+                pt = re.search(r'\(\s*{0}\s*,\s*{0}\s*\)'.format(float_re),
+                               lines[6 + i])
+                point = float(pt.group(1)), float(pt.group(2))
+                points.append(point)
+            barcodes.append({'format': _format, 'points': points,
+                             'raw_data': raw_result, 'data': parsed_result})
+
+        return {'zxing:Barcodes': barcodes}

tests/image/image_file_test.py

@@ -86,3 +86,50 @@ def test_facial_landmarks_baby_face(self):
         data = self.baby_face.analyze_facial_landmarks()
         self.assertIn('dlib:Faces', data)
         self.assertEqual(len(data['dlib:Faces']), 1)
+
+
+class ImageFileBarcodesTest(unittest.TestCase):
+
+    def setUp(self):
+        self.mona_lisa = ImageFile(fetch_file('mona_lisa.jpg'))
+        self.multibarcodes = ImageFile(fetch_file('multibarcodes.png'))
+        self.barcode = ImageFile(fetch_file('barcode.png'))
+        self.qrcode = ImageFile(fetch_file('qrcode.jpg'))
+        self.dmtx = ImageFile(fetch_file('datamatrix.png'))
+
+    def test_mona_lisa(self):
+        data = self.mona_lisa.analyze_barcode()
+        self.assertEqual(data, {})
+
+    def test_barcode(self):
+        data = self.barcode.analyze_barcode()
+        self.assertIn('zxing:Barcodes', data)
+        self.assertEqual(len(data['zxing:Barcodes']), 1)
+        self.assertEqual(data['zxing:Barcodes'][0]['format'], 'CODABAR')
+        self.assertEqual(data['zxing:Barcodes'][0]['data'], '137255')
+
+    def test_qrcode(self):
+        data = self.qrcode.analyze_barcode()
+        self.assertIn('zxing:Barcodes', data)
+        self.assertEqual(len(data['zxing:Barcodes']), 1)
+        self.assertEqual(data['zxing:Barcodes'][0]['format'], 'QR_CODE')
+        self.assertEqual(data['zxing:Barcodes'][0]['data'],
+                         'http://www.wikipedia.com')
+
+    def test_dmtx(self):
+        data = self.dmtx.analyze_barcode()
+        self.assertIn('zxing:Barcodes', data)
+        self.assertEqual(len(data['zxing:Barcodes']), 1)
+        self.assertEqual(data['zxing:Barcodes'][0]['format'], 'DATA_MATRIX')
+        self.assertEqual(data['zxing:Barcodes'][0]['data'],
+                         'Wikipedia, the free encyclopedia')
+
+    def test_multiple_barcodes(self):
+        data = self.multibarcodes.analyze_barcode()
+        self.assertIn('zxing:Barcodes', data)
+        self.assertEqual(len(data['zxing:Barcodes']), 2)
+        self.assertEqual(data['zxing:Barcodes'][0]['format'], 'CODE_128')
+        self.assertEqual(data['zxing:Barcodes'][0]['data'],
+                         '2LUS94941+67000000')
+        self.assertEqual(data['zxing:Barcodes'][1]['format'], 'ITF')
+        self.assertEqual(data['zxing:Barcodes'][1]['data'], '054804124097')