Merge pull request #264 from googlefonts/fix-relative-move-after-empt…

…y-subpath

make subpath moveto absolute before removing empty ones

src/picosvg/svg_types.py

@@ -94,6 +94,12 @@ def _relative_to_absolute(curr_pos, cmd, args):
     )
 
 
+def _relative_to_absolute_moveto(curr_pos, cmd, args):
+    if cmd in ("M", "m"):
+        return _relative_to_absolute(curr_pos, cmd, args)
+    return (cmd, args)
+
+
 def _absolute_to_relative(curr_pos, cmd, args):
     return _rewrite_coords(
         lambda cmd: cmd.lower(), lambda curr_scaler: -curr_scaler, curr_pos, cmd, args
@@ -516,7 +522,9 @@ def subpaths_callback(subpath_start, curr_pos, cmd, args, *_unused):
                 subpaths.append(SVGPath())
             return ((cmd, args),)  # unmodified
 
-        self.walk(subpaths_callback)
+        # make all moveto absolute so each subpath is independent from the
+        # precending ones
+        self.absolute_moveto().walk(subpaths_callback)
 
         return tuple(s.d for s in subpaths if s.d)
 
@@ -578,6 +586,10 @@ def absolute(self, inplace=False) -> "SVGPath":
         """Returns equivalent path with only absolute commands."""
         return self._rewrite_path(_relative_to_absolute, inplace)
 
+    def absolute_moveto(self, inplace=False) -> "SVGPath":
+        """Returns equivalent path with absolute moveto commands."""
+        return self._rewrite_path(_relative_to_absolute_moveto, inplace)
+
     def relative(self, inplace=False) -> "SVGPath":
         """Returns equivalent path with only relative commands."""
         return self._rewrite_path(_absolute_to_relative, inplace)

tests/svg_types_test.py

@@ -75,6 +75,24 @@ def test_path_absolute(path: str, expected_result: str):
     assert actual == expected_result
 
 
+@pytest.mark.parametrize(
+    "path, expected_result",
+    [
+        (
+            "m0,0 l1,1 l0,-1 m1,2 l1,1 l0,-1 z M3,3 l1,1 l0,-1 Z",
+            "M0,0 l1,1 l0,-1 M2,2 l1,1 l0,-1 z M3,3 l1,1 l0,-1 Z",
+        ),
+    ],
+)
+def test_path_absolute_moveto(path: str, expected_result: str):
+    actual = (
+        SVGPath(d=path).absolute_moveto(inplace=True).round_floats(3, inplace=True).d
+    )
+    print(f"A: {actual}")
+    print(f"E: {expected_result}")
+    assert actual == expected_result
+
+
 @pytest.mark.parametrize(
     "path, move, expected_result",
     [
@@ -475,10 +493,24 @@ def test_gradient_from_element(el, view_box, expected):
         ("M1,2", ""),
         ("M1,2 z", ""),
         ("m1,1 2,2 1,3 z M465,550 Z M1,2", "M1,1 l2,2 l1,3 z"),
+        ("m1,1 2,2 1,3 z M465,550 Z M1,2", "M1,1 l2,2 l1,3 z"),
+        # the following path (from noto-emoji "foot" emoji_u1f9b6.svg) contains a
+        # subpath starting with relative 'm' that follows an empty subpath. Check
+        # the latter is removed and the subsequent 'M' is correctly absolutized.
+        # https://github.com/googlefonts/picosvg/issues/252#issuecomment-1026839746
+        (
+            "M0,0 c0.59,-0.63 1.39,-0.97 2.25,-0.97 m103.99,90.92 m-103.99,-93.92 c-3.52,0 -6.3,2.97 -6.07,6.48",
+            "M0,0 c0.59,-0.63 1.39,-0.97 2.25,-0.97 M2.25,-3.97 c-3.52,0 -6.3,2.97 -6.07,6.48",
+        ),
     ],
 )
 def test_remove_empty_subpaths(path: str, expected_result: str):
-    actual = SVGPath(d=path).remove_empty_subpaths(inplace=True).d
+    actual = (
+        SVGPath(d=path)
+        .remove_empty_subpaths(inplace=True)
+        .round_floats(3, inplace=True)
+        .d
+    )
     print(f"A: {actual}")
     print(f"E: {expected_result}")
     assert actual == expected_result