High-level API for decoding images via PIL

svartalf · svartalf · commit 2c1fa0533195 · 2012-05-23T17:09:23.000+09:00
diff --git a/README.md b/README.md
@@ -16,6 +16,19 @@ When version 1.0.0 will be released the API will be frozen, and any changes whic
 
 ## Usage
 
+### High-level API
+
+Just call a `quirc.decode()` function with a PIL.Image object as a parameter, like this:
+
+    import Image
+
+    image = Image.open('tests/images/test1.png')
+    for code in quirc.decode(image):
+        print code['text']
+        # >>> test1
+
+Currently only PIL is supported.
+
 ### Low-level API
 
 Low-level API directly corresponds to the C API:
diff --git a/quirc/__init__.py b/quirc/__init__.py
@@ -3,7 +3,75 @@
 
 """Bindings to QR code decoding library `quirc`"""
 
+import ctypes
+
 from quirc import api
 
-__version__ = '0.5.0'
-__all__ = ('api',)
+USING_PIL = True
+try:
+    from PIL import Image
+except ImportError:
+    try:
+        import Image
+    except ImportError:
+        USING_PIL = False
+
+__version__ = '0.6.0'
+__all__ = ('api', 'decode')
+
+
+def decode(image):
+    """Recognize image and return generator with all the available QR codes
+
+    Currently supports only PIL Image object as an parameter
+    """
+
+    if not (USING_PIL and isinstance(image, Image.Image)):
+        raise TypeError('Unknown image object type: %s' % type(image))
+
+    # Convert to grayscale mode
+    if image.mode not in ('1', 'L'):
+        image = image.convert('L')
+
+    width, height = image.size
+    pixels = image.load()
+
+    obj = api.new()
+    api.resize(obj, width, height)
+    buffer = api.begin(obj, width, height)
+
+    # Fill buffer with a image pixels. One cell, one pixel.
+    # TODO: looks like a very slow operation
+    idx = 0
+    for i in range(width):
+        for j in range(height):
+            buffer[idx] = ctypes.c_uint8(pixels[j, i])
+            idx += 1
+
+    del idx
+
+    # Finish codes identification
+    api.end(obj)
+
+    num_codes = api.count(obj)
+
+    code = api.structures.Code()
+    data = api.structures.Data()
+
+    for i in range(num_codes):
+
+        # Extract first code
+        api.extract(obj, i, code)
+        api.decode(code, data)
+
+        yield {
+            'corners': tuple([(corner.x, corner.y) for corner in code.corners]),
+            'size': code.size,
+            'version': data.version,
+            'ecc_level': data.ecc_level,
+            'mask': data.mask,
+            'data_type': data.data_type,
+            'text': ctypes.string_at(data.payload, data.payload_len),
+        }
+
+    api.destroy(obj)
diff --git a/tests/images/link.gif b/tests/images/link.gif
diff --git a/tests/test_quirc.py b/tests/test_quirc.py
@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+
+import os.path
+import unittest
+
+import quirc
+
+USING_PIL = True
+try:
+    import Image
+except ImportError:
+    try:
+        from PIL import Image
+    except ImportError:
+        USING_PIL = False
+
+
+class TestQuircCase(unittest.TestCase):
+
+    def setUp(self):
+        self._folder = os.path.abspath(os.path.dirname(__file__))
+
+    @unittest.skipIf(not USING_PIL, 'PIL is unaccessible')
+    def test_pil(self):
+        image = Image.open(os.path.join(self._folder, 'images', 'link.gif'))
+
+        result = list(quirc.decode(image))
+
+        self.assertEqual(len(result), 1)
+
+        code = result[0]
+
+        self.assertEqual(code['data_type'], 4)
+        self.assertEqual(code['mask'], 6)
+        self.assertEqual(code['ecc_level'], 0)
+        self.assertEqual(code['size'], 29)
+
+        self.assertTupleEqual(code['corners'], ((16, 16), (132, 16), (132, 132), (16, 132)))
+        self.assertEqual(code['text'], 'https://github.com/svartalf/python-quirc')
