Merge pull request #12 from globophobe/master

Add location/position support

README.md

@@ -49,8 +49,8 @@ The `decode` function accepts instances of `PIL.Image`.
 >>> from pyzbar.pyzbar import decode
 >>> from PIL import Image
 >>> decode(Image.open('pyzbar/tests/code128.png'))
-[Decoded(data=b'Foramenifera', type='CODE128'),
- Decoded(data=b'Rana temporaria', type='CODE128')]
+[Decoded(data=b'Foramenifera', type='CODE128', rect=Rect(left=37, top=550, width=324, height=76)),
+Decoded(data=b'Rana temporaria', type='CODE128', rect=Rect(left=4, top=0, width=390, height=76))]
 ```
 
 It also accepts instances of `numpy.ndarray`, which might come from loading
@@ -59,8 +59,8 @@ images using [OpenCV](http://opencv.org/).
 ```
 >>> import cv2
 >>> decode(cv2.imread('pyzbar/tests/code128.png'))
-[Decoded(data=b'Foramenifera', type='CODE128'),
- Decoded(data=b'Rana temporaria', type='CODE128')]
+[Decoded(data=b'Foramenifera', type='CODE128', rect=Rect(left=37, top=550, width=324, height=76)),
+Decoded(data=b'Rana temporaria', type='CODE128', rect=Rect(left=4, top=0, width=390, height=76))]
 ```
 
 You can also provide a tuple `(pixels, width, height)`, where the image data
@@ -72,14 +72,14 @@ is eight bits-per-pixel.
 
 >>> # 8 bpp by considering just the blue channel
 >>> decode((image[:, :, 0].astype('uint8').tobytes(), width, height))
-[Decoded(data=b'Foramenifera', type='CODE128'),
- Decoded(data=b'Rana temporaria', type='CODE128')]
+[Decoded(data=b'Foramenifera', type='CODE128', rect=Rect(left=37, top=550, width=324, height=76)),
+Decoded(data=b'Rana temporaria', type='CODE128', rect=Rect(left=4, top=0, width=390, height=76))]
 
 >>> # 8 bpp by converting image to greyscale
 >>> grey = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
 >>> decode((grey.tobytes(), width, height))
-[Decoded(data=b'Foramenifera', type='CODE128'),
- Decoded(data=b'Rana temporaria', type='CODE128')]
+[Decoded(data=b'Foramenifera', type='CODE128', rect=Rect(left=37, top=550, width=324, height=76)),
+Decoded(data=b'Rana temporaria', type='CODE128', rect=Rect(left=4, top=0, width=390, height=76))]
 
 >>> # If you don't provide 8 bpp
 >>> decode((image.tobytes(), width, height))
@@ -98,7 +98,7 @@ effect of this on performance)
 >>> from pyzbar.pyzbar import ZBarSymbol
 >>> # Look for just qrcode
 >>> decode(Image.open('pyzbar/tests/qrcode.png'), symbols=[ZBarSymbol.QRCODE])
-[Decoded(data=b'Thalassiodracon', type='QRCODE')]
+[Decoded(data=b'Thalassiodracon', type='QRCODE', rect=Rect(left=27, top=27, width=145, height=145))]
 
 >>> # If we look for just code128, the qrcodes in the image will not be detected
 >>> decode(Image.open('pyzbar/tests/qrcode.png'), symbols=[ZBarSymbol.CODE128])

pyzbar/pyzbar.py

@@ -1,5 +1,6 @@
 from __future__ import print_function
 
+from operator import itemgetter
 from collections import namedtuple
 from contextlib import contextmanager
 from ctypes import cast, c_void_p, string_at
@@ -11,14 +12,19 @@
     zbar_image_create, zbar_image_destroy, zbar_image_set_format,
     zbar_image_set_size, zbar_image_set_data, zbar_scan_image,
     zbar_image_first_symbol, zbar_symbol_get_data,
+    zbar_symbol_get_loc_size, zbar_symbol_get_loc_x, zbar_symbol_get_loc_y,
     zbar_symbol_next, ZBarConfig, ZBarSymbol, EXTERNAL_DEPENDENCIES
 )
 
 __all__ = ['decode', 'EXTERNAL_DEPENDENCIES']
 
+RANGEFN = getattr(globals(), 'xrange', range)
+
+# A rectangle
+Rect = namedtuple('Rect', ['left', 'top', 'width', 'height'])
 
 # Results of reading a barcode
-Decoded = namedtuple('Decoded', ['data', 'type'])
+Decoded = namedtuple('Decoded', ['data', 'type', 'rect'])
 
 # ZBar's magic 'fourcc' numbers that represent image formats
 FOURCC = {
@@ -73,6 +79,23 @@ def zbar_image_scanner():
             zbar_image_scanner_destroy(scanner)
 
 
+def bounding_box_of_locations(locations):
+    """Computes bounding boxes from scan locations.
+
+    Args:
+        locations: :obj:`list` of tuple (x, y) values.
+
+    Returns:
+        :obj:`list` of :obj:`Rect`:  Coordinates of the bounding boxes.
+
+    """
+    x_values = list(map(itemgetter(0), locations))
+    x_min, x_max = min(x_values), max(x_values)
+    y_values = list(map(itemgetter(1), locations))
+    y_min, y_max = min(y_values), max(y_values)
+    return (Rect(x_min, y_min, x_max - x_min,  y_max - y_min))
+
+
 def decode(image, symbols=None):
     """Decodes datamatrix barcodes in `image`.
 
@@ -144,9 +167,20 @@ def decode(image, symbols=None):
                 while symbol:
                     data = string_at(zbar_symbol_get_data(symbol))
                     symbol_type = ZBarSymbol(symbol.contents.value).name
+
+                    loc = zbar_symbol_get_loc_size(symbol)
+                    locations = [
+                        (
+                            zbar_symbol_get_loc_x(symbol, l),
+                            zbar_symbol_get_loc_y(symbol, l)
+                        )
+                        for l in RANGEFN(loc)
+                    ]
+
                     results.append(Decoded(
                         data=data,
-                        type=symbol_type
+                        type=symbol_type,
+                        rect=bounding_box_of_locations(locations)
                     ))
 
                     symbol = zbar_symbol_next(symbol)

pyzbar/tests/test_decode.py

@@ -13,7 +13,9 @@
     cv2 = None
 
 
-from pyzbar.pyzbar import decode, Decoded, ZBarSymbol, EXTERNAL_DEPENDENCIES
+from pyzbar.pyzbar import (
+    decode, Rect, Decoded, ZBarSymbol, EXTERNAL_DEPENDENCIES
+)
 from pyzbar.pyzbar_error import PyZbarError
 
 
@@ -24,20 +26,24 @@ class TestDecode(unittest.TestCase):
     EXPECTED_CODE128 = [
         Decoded(
             data=b'Foramenifera',
-            type='CODE128'
+            type='CODE128',
+            rect=Rect(left=37, top=550, width=324, height=76)
         ),
         Decoded(
             data=b'Rana temporaria',
-            type='CODE128'
+            type='CODE128',
+            rect=Rect(left=4, top=0, width=390, height=76)
         )
     ]
 
     EXPECTED_QRCODE = [
         Decoded(
             b'Thalassiodracon',
-            type='QRCODE'
+            type='QRCODE',
+            rect=Rect(left=27, top=27, width=145, height=145)
         )
     ]
+
     def setUp(self):
         self.code128 = Image.open(str(TESTDATA.joinpath('code128.png')))
         self.qrcode = Image.open(str(TESTDATA.joinpath('qrcode.png')))

pyzbar/wrapper.py

@@ -261,6 +261,26 @@ def zbar_function(fname, restype, *args):
     POINTER(c_int)         # values in ZBarSymbol
 )
 
+zbar_symbol_get_loc_size = zbar_function(
+    'zbar_symbol_get_loc_size',
+    c_uint,
+    POINTER(c_int)         # values in ZBARSymbol
+)
+
+zbar_symbol_get_loc_x = zbar_function(
+    'zbar_symbol_get_loc_x',
+    c_int,
+    POINTER(c_int),        # values in ZBARSymbol
+    c_uint
+)
+
+zbar_symbol_get_loc_y = zbar_function(
+    'zbar_symbol_get_loc_y',
+    c_int,
+    POINTER(c_int),        # values in ZBARSymbol
+    c_uint
+)
+
 zbar_symbol_next = zbar_function(
     'zbar_symbol_next',
     POINTER(c_int),