Cloned DMOJ

judge/jinja2/markdown/lazy_load.py

@@ -0,0 +1,20 @@
+from copy import deepcopy
+
+from django.templatetags.static import static
+from lxml import html
+
+
+def lazy_load(tree):
+    blank = static('blank.gif')
+    for img in tree.xpath('.//img'):
+        src = img.get('src', '')
+        if src.startswith('data') or '-math' in img.get('class', ''):
+            continue
+        noscript = html.Element('noscript')
+        copy = deepcopy(img)
+        copy.tail = ''
+        noscript.append(copy)
+        img.addprevious(noscript)
+        img.set('data-src', src)
+        img.set('src', blank)
+        img.set('class', img.get('class') + ' unveil' if img.get('class') else 'unveil')