SVG stroke-width with explicit unit, fixes py-pdf#526

CHANGELOG.md

@@ -29,6 +29,7 @@ This can also be enabled programmatically with `warnings.simplefilter('default',
 - `fpdf2` now uses [fontTools](https://fonttools.readthedocs.io/en/latest/) to read and embed fonts in the PDF, thanks to @gmischler and @RedShy
 
 ### Fixed
+- The SVG parser now accepts stroke-width attribute values with an explicit unit, thanks to @gmischler; [#526](https://github.com/PyFPDF/fpdf2/issues/526)
 - Text following a HTML heading can't overlap with that heading anymore, thanks to @gmischler
 - `arc()` not longer renders artefacts at intersection point, thanks to @Jmillan-Dev; [#488](https://github.com/PyFPDF/fpdf2/issues/488)
 - [`write_html()`](https://pyfpdf.github.io/fpdf2/HTML.html):

fpdf/svg.py

@@ -119,7 +119,10 @@ class Percent(float):
 @force_nodocument
 def resolve_length(length_str, default_unit="pt"):
     """Convert a length unit to our canonical length unit, pt."""
-    value, unit = unit_splitter.match(length_str).groups()
+    match = unit_splitter.match(length_str)
+    if match == None:
+        raise ValueError(f"Unable to parse '{length_str}' as a length") from None
+    value, unit = match.groups()
     if not unit:
         unit = default_unit
 
@@ -193,7 +196,7 @@ def svgcolor(colorstr):
 
 @force_nodocument
 def convert_stroke_width(incoming):
-    val = float(incoming)
+    val = resolve_length(incoming)
     if val < 0:
         raise ValueError(f"stroke width {incoming} cannot be negative")
     if val == 0:

test/svg/parameters.py

@@ -580,6 +580,12 @@ def Gs(**kwargs):
         no_error(),
         id="stroke-width number",
     ),
+    pytest.param(  # issue #526
+        '<path stroke-width="2px"/>',
+        Gs(stroke_width=2 * 0.75),
+        no_error(),
+        id="stroke-width number",
+    ),
     pytest.param(
         '<path stroke-width="inherit"/>',
         Gs(),