Honor baseunit when deriving SVG dimensions from viewBox

svgpathtools/paths2svg.py

@@ -162,6 +162,10 @@ def disvg(paths=None, colors=None, filename=None, stroke_widths=None,
         these also can be used to specify units other than pixels. Using this 
         will override the `mindim` parameter.
 
+        :param baseunit - Unit string for inferred display dimensions (default
+        'px'). Viewbox-derived pixel dimensions retain unitless serialization.
+        Explicit `dimensions` and `svg_attributes` take precedence.
+
         :param viewbox - This specifies the coordinated system used in the svg.
         The SVG `viewBox` attribute works together with the the `height` and 
         `width` attrinutes.  Using these three attributes allows for shifting 
@@ -264,6 +268,8 @@ def disvg(paths=None, colors=None, filename=None, stroke_widths=None,
             viewbox = '%s %s %s %s' % viewbox
         if dimensions is None:
             dimensions = viewbox.split(' ')[2:4]
+            if isinstance(baseunit, str) and baseunit != 'px':
+                dimensions = [dimension + baseunit for dimension in dimensions]
     elif dimensions:
         dimensions = tuple(map(str, dimensions))
         def strip_units(s):

test/test_paths2svg.py

@@ -0,0 +1,82 @@
+import unittest
+from os.path import exists, join
+from tempfile import TemporaryDirectory
+import xml.etree.ElementTree as ET
+
+from svgpathtools import Line, Path, disvg, paths2Drawing, wsvg
+
+
+class TestPaths2SVG(unittest.TestCase):
+    def setUp(self):
+        directory = TemporaryDirectory()
+        self.addCleanup(directory.cleanup)
+        self.directory = directory.name
+        self.filename = join(self.directory, 'output.svg')
+        self.path = Path(Line(0, 2.5 + 3.75j))
+
+    def drawing(self, **kwargs):
+        options = dict(filename=self.filename, stroke_widths=[0.1],
+                       svgwrite_debug=True, openinbrowser=False)
+        options.update(kwargs)
+        return ET.fromstring(paths2Drawing(self.path, **options).tostring())
+
+    def test_viewbox_dimensions_use_baseunit(self):
+        cases = [({}, ('2.5', '3.75')),
+                 ({'baseunit': 'px'}, ('2.5', '3.75')),
+                 ({'baseunit': ''}, ('2.5', '3.75')),
+                 ({'baseunit': None}, ('2.5', '3.75')),
+                 ({'baseunit': 'cm'}, ('2.5cm', '3.75cm')),
+                 ({'baseunit': 'mm'}, ('2.5mm', '3.75mm')),
+                 ({'baseunit': 'in'}, ('2.5in', '3.75in')),
+                 ({'baseunit': '%'}, ('2.5%', '3.75%'))]
+        for viewbox in [(1, -2, 2.5, 3.75), '1 -2 2.5 3.75']:
+            for options, expected in cases:
+                with self.subTest(viewbox=viewbox, options=options):
+                    root = self.drawing(viewbox=viewbox, **options)
+                    self.assertEqual((root.get('width'), root.get('height')),
+                                     expected)
+                    self.assertEqual(root.get('viewBox'), '1 -2 2.5 3.75')
+                    element = root.find('{http://www.w3.org/2000/svg}path')
+                    self.assertEqual(element.get('d'), self.path.d())
+        self.assertFalse(exists(self.filename))
+        root = self.drawing(baseunit='cm', mindim=None, margin_size=0,
+                            stroke_widths=[0])
+        self.assertEqual((root.get('width'), root.get('height')),
+                         ('2.5cm', '3.75cm'))
+
+    def test_saved_viewbox_dimensions_use_baseunit(self):
+        for writer in (disvg, wsvg):
+            with self.subTest(writer=writer.__name__):
+                filename = join(self.directory, writer.__name__ + '.svg')
+                writer(self.path, filename=filename, openinbrowser=False,
+                       stroke_widths=[0.1], viewbox=(1, -2, 2.5, 3.75),
+                       baseunit='cm')
+                root = ET.parse(filename).getroot()
+                self.assertEqual((root.get('width'), root.get('height')),
+                                 ('2.5cm', '3.75cm'))
+                self.assertEqual(root.get('viewBox'), '1 -2 2.5 3.75')
+
+    def test_explicit_dimensions_keep_their_units(self):
+        for viewbox in (None, (1, -2, 2.5, 3.75)):
+            for dimensions in (('7mm', '9mm'), (7, 9)):
+                with self.subTest(viewbox=viewbox, dimensions=dimensions):
+                    root = self.drawing(viewbox=viewbox,
+                                        dimensions=dimensions, baseunit='cm')
+                    self.assertEqual((root.get('width'), root.get('height')),
+                                     tuple(map(str, dimensions)))
+
+    def test_svg_attributes_override_inferred_dimensions(self):
+        cases = [({}, ('2.5cm', '3.75cm')),
+                 ({'width': '7in'}, ('7in', '3.75cm')),
+                 ({'height': '9in'}, ('2.5cm', '9in')),
+                 ({'width': '7in', 'height': '9in',
+                   'viewBox': '0 0 7 9'}, ('7in', '9in'))]
+        for attributes, expected in cases:
+            with self.subTest(attributes=attributes):
+                root = self.drawing(viewbox=(1, -2, 2.5, 3.75), baseunit='cm',
+                                    svg_attributes=attributes)
+                self.assertEqual((root.get('width'), root.get('height')),
+                                 expected)
+                if 'viewBox' in attributes:
+                    self.assertEqual(root.get('viewBox'),
+                                     attributes['viewBox'])