Fix relative paths for SVG files stored as data URLs

Fix #1641.

tests/draw/svg/test_defs.py

@@ -1,34 +1,51 @@
 """Test how SVG definitions are drawn."""
 
+from base64 import b64encode
+
 from ...testing_utils import assert_no_logs
 from .. import assert_pixels
 
+SVG = '''
+<svg width="10px" height="10px" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <rect id="rectangle" width="5" height="2" fill="red" />
+  </defs>
+  <use href="#rectangle" />
+  <use href="#rectangle" x="3" y="3" />
+  <use href="#rectangle" x="5" y="6" />
+</svg>
+'''
+
+RESULT = '''
+  RRRRR_____
+  RRRRR_____
+  __________
+  ___RRRRR__
+  ___RRRRR__
+  __________
+  _____RRRRR
+  _____RRRRR
+  __________
+  __________
+'''
+
 
 @assert_no_logs
 def test_use():
-    assert_pixels('use', 10, 10, '''
-        RRRRR_____
-        RRRRR_____
-        __________
-        ___RRRRR__
-        ___RRRRR__
-        __________
-        _____RRRRR
-        _____RRRRR
-        __________
-        __________
-    ''', '''
+    assert_pixels('use', 10, 10, RESULT, '''
       <style>
         @page { size: 10px }
         svg { display: block }
       </style>
-      <svg width="10px" height="10px" xmlns="http://www.w3.org/2000/svg"
-           xlink="http://www.w3.org/1999/xlink">
-        <defs>
-          <rect id="rectangle" width="5" height="2" fill="red" />
-        </defs>
-        <use xlink:href="#rectangle" />
-        <use xlink:href="#rectangle" x="3" y="3" />
-        <use xlink:href="#rectangle" x="5" y="6" />
-      </svg>
-    ''')
+    ''' + SVG)
+
+
+@assert_no_logs
+def test_use_base64():
+    base64_svg = b64encode(SVG.encode()).decode()
+    assert_pixels('use_base64', 10, 10, RESULT, '''
+      <style>
+        @page { size: 10px }
+        img { display: block }
+      </style>
+      <img src="data:image/svg+xml;base64,''' + base64_svg + '"/>')

weasyprint/svg/defs.py

@@ -21,7 +21,10 @@ def use(svg, node, font_size):
             del node.attrib[attribute]
 
     parsed_url = parse_url(node.get_href(svg.url))
-    if parsed_url.fragment and parsed_url[:3] == parse_url(svg.url)[:3]:
+    svg_url = parse_url(svg.url)
+    if svg_url.scheme == 'data':
+        svg_url = parse_url('')
+    if parsed_url.fragment and parsed_url[:3] == svg_url[:3]:
         if parsed_url.fragment in svg.use_cache:
             tree = svg.use_cache[parsed_url.fragment].copy()
         else: