New setting to disable autorotation of images, and warn about the

incompatibility between autorotation and EXIF copy (ref #72).

docs/changelog.rst

@@ -20,6 +20,8 @@ Released on 2014-xx-xx.
 
 - New settings to define the sort order for albums and medias:
   ``albums_sort_reverse``, ``medias_sort_attr``, ``medias_sort_reverse``.
+- New setting ``autorotate_images`` to disable autorotation of images, and warn
+  about the incompatibility between autorotation and EXIF copy.
 
 Version 0.6.0
 ~~~~~~~~~~~~~

sigal/image.py

@@ -64,6 +64,11 @@ def generate_image(source, outname, settings, options=None):
     img = PILImage.open(source)
     original_format = img.format
 
+    if settings['copy_exif_data'] and settings['autorotate_images']:
+        logger.warning("The 'autorotate_images' and 'copy_exif_data' settings "
+                       "are not compatible because Sigal can't save the "
+                       "modified Orientation tag.")
+
     # Preserve EXIF data
     if settings['copy_exif_data'] and _has_exif_tags(img):
         if options is not None:
@@ -73,10 +78,11 @@ def generate_image(source, outname, settings, options=None):
         options['exif'] = img.info['exif']
 
     # Rotate the img, and catch IOError when PIL fails to read EXIF
-    try:
-        img = Transpose().process(img)
-    except (IOError, IndexError):
-        pass
+    if settings['autorotate_images']:
+        try:
+            img = Transpose().process(img)
+        except (IOError, IndexError):
+            pass
 
     # Resize the image
     if settings['img_processor']:

sigal/settings.py

@@ -32,7 +32,8 @@
     'adjust_options': {'color': 1.0, 'brightness': 1.0,
                        'contrast': 1.0, 'sharpness': 1.0},
     'albums_sort_reverse': False,
-    'copy_exif_data': True,
+    'autorotate_images': True,
+    'copy_exif_data': False,
     'copyright': '',
     'destination': '_build',
     'files_to_copy': (),

sigal/templates/sigal.conf.py

@@ -107,8 +107,14 @@
 # contain all original files.
 # zip_gallery = False   # False or 'archive.zip'
 
+# Autorotate images
+# Warning: this setting is not compatible with `copy_exif_data` (see below),
+# because Sigal can't save the modified Orientation tag (currently Pillow can't
+# write EXIF).
+# autorotate_images = True
+
 # If True, EXIF data from the original image is copied to the resized image
-# copy_exif_data = True
+# copy_exif_data = False
 
 # Specify a different locale. If set to '', the default locale is used.
 # locale = ''