incorect dimensions with only one of width or height?

svgelements/svgelements.py

@@ -9146,6 +9146,20 @@ def parse(
                     # explicit transform, parent transforms, attribute transforms, viewport transforms
                     s = SVG(values)
 
+                    # if we have only one of `s.width` and `s.height` we can deduce the other one
+                    # assuming we have a viewbox.
+                    if s.viewbox is not None:
+                        has_absolute_width = isinstance(s.width, float) or (
+                            isinstance(s.width, Length) and s.width.units != "%"
+                        )
+                        has_absolute_height = isinstance(s.height, float) or (
+                            isinstance(s.height, Length) and s.height.units != "%"
+                        )
+                        if width is None and has_absolute_width and not has_absolute_height:
+                            s.height = s.width * s.viewbox.height / s.viewbox.width
+                        elif height is None and not has_absolute_width and has_absolute_height:
+                            s.width = s.height * s.viewbox.width / s.viewbox.height
+
                     if width is None:
                         # If a dim was not provided but a viewbox was, use the viewbox dim as physical size, else 1000
                         width = (

test/test_viewbox.py

@@ -134,6 +134,50 @@ def test_viewbox_incomplete_height_viewbox(self):
         self.assertEqual(m.width, 200)
         self.assertEqual(m.height, 200)
 
+    def test_viewbox_incomplete_height_viewbox_default_dimensions(self):
+        q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
+                        <svg viewBox="0, 0, 100, 200" height="400"/>''')
+        m = SVG.parse(q)
+        self.assertEqual(Matrix(m.viewbox_transform), 'scale(2)')
+        self.assertEqual(m.width, 2 * 100)
+        self.assertEqual(m.height, 2 * 200)
+
+        q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
+                        <svg viewBox="0, 0, 100, 200" height="10in"/>''')
+        m = SVG.parse(q)
+        self.assertEqual(Matrix(m.viewbox_transform), 'scale(4.8)')
+        self.assertEqual(m.width, 4.8 * 100)
+        self.assertEqual(m.height, 4.8 * 200)
+
+        q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
+                        <svg viewBox="0, 0, 100, 200" height="100%"/>''')
+        m = SVG.parse(q)
+        self.assertEqual(Matrix(m.viewbox_transform), 'scale(1)')
+        self.assertEqual(m.width, 100)
+        self.assertEqual(m.height, 200)
+
+    def test_viewbox_incomplete_width_viewbox_default_dimensions(self):
+        q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
+                        <svg viewBox="0, 0, 100, 200" width="400"/>''')
+        m = SVG.parse(q)
+        self.assertEqual(Matrix(m.viewbox_transform), 'scale(4)')
+        self.assertEqual(m.width, 4 * 100)
+        self.assertEqual(m.height, 4 * 200)
+
+        q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
+                        <svg viewBox="0, 0, 100, 200" width="10in"/>''')
+        m = SVG.parse(q)
+        self.assertEqual(Matrix(m.viewbox_transform), 'scale(9.6)')
+        self.assertEqual(m.width, 9.6 * 100)
+        self.assertEqual(m.height, 9.6 * 200)
+
+        q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
+                        <svg viewBox="0, 0, 100, 200" width="100%"/>''')
+        m = SVG.parse(q)
+        self.assertEqual(Matrix(m.viewbox_transform), 'scale(1)')
+        self.assertEqual(m.width, 100)
+        self.assertEqual(m.height, 200)
+
     def test_viewbox_aspect_ratio_xMinMax(self):
         q = io.StringIO(u'''<?xml version="1.0" encoding="utf-8" ?>
                         <svg preserveAspectRatio="xMid" viewBox="0 0 100 100" height="100" width="300"/>''')