Limit image size, fixes #4464.

[librarian.git] / src / librarian / elements / figures / ilustr.py

diff --git a/src/librarian/elements/figures/ilustr.py b/src/librarian/elements/figures/ilustr.py
index c6105f4..4e848ac 100644 (file)
--- a/src/librarian/elements/figures/ilustr.py
+++ b/src/librarian/elements/figures/ilustr.py
@@ -1,34 +1,57 @@
-import six.moves
+# This file is part of Librarian, licensed under GNU Affero GPLv3 or later.
+# Copyright © Fundacja Wolne Lektury. See NOTICE for more information.
+#
+import io
+import urllib.parse
+import urllib.request
 from PIL import Image
 from ..base import WLElement
 
 
+MAX_PNG_WEIGHT = 200000
+
+
 class Ilustr(WLElement):
+    SHOULD_HAVE_ID = True
+
     EPUB_TAG = HTML_TAG = 'img'
 
     def get_html_attr(self, builder):
         ## TODO: thumbnail.
 
-        url = six.moves.urllib.parse.urljoin(
+        url = urllib.parse.urljoin(
             builder.base_url,
             self.get('src')
         )
         
-        imgfile = six.moves.urllib.request.urlopen(url)
+        imgfile = urllib.request.urlopen(url)
         img = Image.open(imgfile)
         th_format, ext, media_type = {
             'GIF': ('GIF', 'gif', 'image/gif'),
             'PNG': ('PNG', 'png', 'image/png'),
         }.get(img.format, ('JPEG', 'jpg', 'image/jpeg'))
 
-        width = 1200
+        width = 600
         if img.size[0] < width:
             th = img
         else:
             th = img.resize((width, round(width * img.size[1] / img.size[0])))
 
-        buffer = six.BytesIO()
+        buffer = io.BytesIO()
         th.save(buffer, format=th_format)
+
+        # Limit PNG to 200K. If larger, convert to JPEG.
+        if th_format == 'PNG' and buffer.tell() > MAX_PNG_WEIGHT:
+            th_format, ext, media_type = 'JPEG', 'jpg', 'image/jpeg'
+            if th.mode != 'RGB':
+                buffer = io.BytesIO()
+                th = Image.alpha_composite(
+                    Image.new('RGBA', th.size, '#fff'),
+                    th.convert('RGBA')
+                )
+                th = th.convert('RGB')
+            th.save(buffer, format=th_format)
+
         imgfile.close()
         file_name = 'image%d.%s' % (
             builder.assign_image_number(),
@@ -43,8 +66,8 @@ class Ilustr(WLElement):
         
         return {
             'src': file_name,
-            'alt': self.attrib['alt'],
-            'title': self.attrib['alt'],
+            'alt': self.attrib.get('alt', ''),
+            'title': self.attrib.get('alt', ''),
         }
 
     get_epub_attr = get_html_attr