img: add GIF formats to recognizer

Steve Canny · Steve Canny · commit 4434b1c3acef · 2014-02-27T12:08:33.000-08:00
diff --git a/docx/image/__init__.py b/docx/image/__init__.py
@@ -19,6 +19,7 @@
 
 from docx.compat import BytesIO, is_string
 from docx.exceptions import UnrecognizedImageError
+from docx.image.gif import Gif
 from docx.image.jpeg import Exif, Jfif
 from docx.image.png import Png
 from docx.opc.constants import CONTENT_TYPE as CT
@@ -30,6 +31,8 @@
     (Png,  0, b'\x89PNG\x0D\x0A\x1A\x0A'),
     (Jfif, 6, b'JFIF'),
     (Exif, 6, b'Exif'),
+    (Gif,  0, b'GIF87a'),
+    (Gif,  0, b'GIF89a'),
 )
 
 
diff --git a/docx/image/gif.py b/docx/image/gif.py
@@ -0,0 +1,13 @@
+# encoding: utf-8
+
+from __future__ import absolute_import, division, print_function
+
+from .image import Image
+
+
+class Gif(Image):
+    """
+    Image header parser for GIF images. Note that the GIF format does not
+    support resolution (DPI) information. Both horizontal and vertical DPI
+    default to 72.
+    """
diff --git a/tests/image/test_image.py b/tests/image/test_image.py
@@ -11,6 +11,7 @@
 from docx.compat import BytesIO
 from docx.exceptions import UnrecognizedImageError
 from docx.image import image_cls_that_can_parse, Image_OLD
+from docx.image.gif import Gif
 from docx.image.image import Image
 from docx.image.jpeg import Exif, Jfif
 from docx.image.png import Png
@@ -40,6 +41,7 @@ def it_raises_on_unrecognized_image_stream(self):
         ('python-icon.png',  Png),
         ('python-icon.jpeg', Jfif),
         ('exif-420-dpi.jpg', Exif),
+        ('sonic.gif',        Gif),
     ])
     def image_cls_lookup_fixture(self, request):
         image_filename, expected_class = request.param
