From: Vladimír Vondruš <mosra@centrum.cz>
Date: Fri, 1 Dec 2017 10:33:07 +0000 (+0100)
Subject: m.images: don't freak out if there's no EXIF.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~cjwatson/git?a=commitdiff_plain;h=525dedb96b43ce87e00a842c51a3b24f8877e71e;p=blog.git

m.images: don't freak out if there's no EXIF.

Instead it just doesn't display anything as a caption.
---

diff --git a/doc/plugins/images-test.rst b/doc/plugins/images-test.rst
index cea68ab8..e3c49f47 100644
--- a/doc/plugins/images-test.rst
+++ b/doc/plugins/images-test.rst
@@ -81,3 +81,9 @@ Image grid, inflated:
 
         {filename}/static/flowers.jpg
         {filename}/static/ship.jpg
+
+Image grid with a PNG file:
+
+.. image-grid::
+
+    {filename}/static/tiny.png
diff --git a/doc/plugins/images.rst b/doc/plugins/images.rst
index 24570008..7cf64e63 100644
--- a/doc/plugins/images.rst
+++ b/doc/plugins/images.rst
@@ -125,10 +125,10 @@ option for both images and figures.
 Use the :rst:`.. image-grid::` directive for creating
 `image grid <{filename}/css/components.rst#image-grid>`_. Directive contents
 are a list of image URLs, blank lines separate grid rows. The plugin
-automatically extracts size information and scales the images accordingly, in
-addition EXIF properties such as aperture, shutter speed and ISO are extracted
-and displayed in the caption on hover. The images are also made clickable, the
-target is the image file itself.
+automatically extracts size information and scales the images accordingly. If
+the image has EXIF information, properties such as aperture, shutter speed and
+ISO are extracted and displayed in the caption on hover. The images are also
+made clickable, the target is the image file itself.
 
 Example of a two-row image grid is below. Sorry for reusing the same two images
 all over (I'm making it easier for myself); if you want to see a live example
diff --git a/doc/static/tiny.png b/doc/static/tiny.png
new file mode 100644
index 00000000..cacab704
Binary files /dev/null and b/doc/static/tiny.png differ
diff --git a/pelican-plugins/m/images.py b/pelican-plugins/m/images.py
index 3eaaaf1b..168bb930 100644
--- a/pelican-plugins/m/images.py
+++ b/pelican-plugins/m/images.py
@@ -183,13 +183,20 @@ class ImageGrid(rst.Directive):
             # Open the files and calculate the overall width
             absuri = uri.format(filename=os.path.join(os.getcwd(), settings['PATH']))
             im = PIL.Image.open(absuri)
-            exif = {
-                PIL.ExifTags.TAGS[k]: v
-                for k, v in im._getexif().items()
-                if k in PIL.ExifTags.TAGS and len(str(v)) < 256
-            }
-            # Can't use just *exif['ExposureTime'] on Py3.4
-            caption = "F{}, {}/{} s, ISO {}".format(float(exif['FNumber'][0])/float(exif['FNumber'][1]), exif['ExposureTime'][0], exif['ExposureTime'][1], exif['ISOSpeedRatings'])
+
+            # Get EXIF info, if it's there
+            if hasattr(im, '_getexif'):
+                exif = {
+                    PIL.ExifTags.TAGS[k]: v
+                    for k, v in im._getexif().items()
+                    if k in PIL.ExifTags.TAGS and len(str(v)) < 256
+                }
+                # Can't use just *exif['ExposureTime'] on Py3.4
+                caption = "F{}, {}/{} s, ISO {}".format(float(exif['FNumber'][0])/float(exif['FNumber'][1]), exif['ExposureTime'][0], exif['ExposureTime'][1], exif['ISOSpeedRatings'])
+
+            # It's not (e.g. a PNG file), empty caption
+            else: caption = ""
+
             rel_width = float(im.width)/im.height
             total_widths[-1] += rel_width
             rows[-1].append((uri, rel_width, caption))
@@ -200,10 +207,17 @@ class ImageGrid(rst.Directive):
             for uri, rel_width, caption in row:
                 image_reference = rst.directives.uri(uri)
                 image_node = nodes.image('', uri=image_reference)
-                text_nodes, _ = self.state.inline_text(caption, self.lineno)
-                text_node = nodes.paragraph('', '', *text_nodes)
-                overlay_node = nodes.caption()
-                overlay_node.append(text_node)
+
+                # <figurecaption> in case there's a caption
+                if caption:
+                    text_nodes, _ = self.state.inline_text(caption, self.lineno)
+                    text_node = nodes.paragraph('', '', *text_nodes)
+                    overlay_node = nodes.caption()
+                    overlay_node.append(text_node)
+
+                # Otherwise an empty <div>
+                else: overlay_node = nodes.container()
+
                 link_node = nodes.reference('', refuri=image_reference)
                 link_node.append(image_node)
                 link_node.append(overlay_node)