+def add_image_sizes(tree, gallery_path, gallery_url, base_url):
+ widths = [360, 600, 1200, 1800, 2400]
+
+ for i, ilustr in enumerate(tree.findall('//ilustr')):
+ rel_path = ilustr.attrib['src']
+ img_url = urllib.parse.urljoin(base_url, rel_path)
+
+ f = urllib.request.urlopen(img_url)
+ img = Image.open(f)
+ ext = {'GIF': 'gif', 'PNG': 'png'}.get(img.format, 'jpg')
+
+ srcset = []
+ # Needed widths: predefined and original, limited by
+ # whichever is smaller.
+ img_widths = [
+ w for w in
+ sorted(
+ set(widths + [img.size[0]])
+ )
+ if w <= min(widths[-1], img.size[0])
+ ]
+ largest = None
+ for w in widths:
+ fname = '%d.W%d.%s' % (i, w, ext)
+ fpath = gallery_path + fname
+ if not os.path.exists(fpath):
+ height = round(img.size[1] * w / img.size[0])
+ th = img.resize((w, height))
+ th.save(fpath)
+ th_url = gallery_url + fname
+ srcset.append(" ".join((
+ th_url,
+ '%dw' % w
+ )))
+ largest_url = th_url
+ ilustr.attrib['srcset'] = ", ".join(srcset)
+ ilustr.attrib['src'] = largest_url
+
+ f.close()
+
+
+def transform(wldoc, stylesheet='legacy', options=None, flags=None, css=None, gallery_path='img/', gallery_url='img/', base_url='file://./'):