Keep the hue when lch lightness is none

docs/changelog.rst

@@ -2,6 +2,15 @@ Changelog
 =========
 
 
+Version 1.5.2
+-------------
+
+Unreleased.
+
+* Keep the hue of ``lch()`` and ``oklch()`` when lightness is ``none``.
+  https://github.com/Kozea/tinycss2/issues/80
+
+
 Version 1.5.1
 -------------
 

tests/test_tinycss2.py

@@ -547,6 +547,19 @@ def test_color_oklab_4_with_5(input):
     return result
 
 
+def test_lch_none_lightness_keeps_hue():
+    color = parse_color4("lch(none 50 180)")
+    assert color.coordinates == (None, 50.0, 180.0)
+    color = parse_color4("oklch(none 0.1 180)")
+    assert color.coordinates == (None, 0.1, 180.0)
+    color = parse_color4("lch(50 20 none)")
+    assert color.coordinates == (50.0, 20.0, None)
+    color = parse_color4("lch(40 20 180)")
+    assert color.coordinates == (40.0, 20.0, 180.0)
+    color = parse_color4("lab(none 10 20)")
+    assert color.coordinates == (None, 10.0, 20.0)
+
+
 @json_test()
 def test_color_lch_4(input):
     if not (color := parse_color4(input)):

tinycss2/color4.py

@@ -327,7 +327,7 @@ def _parse_lch(args, alpha):
         None if args[0].type == 'ident' else args[0].value,
         None if args[1].type == 'ident' else (
             args[1].value * (1 if args[1].type == 'number' else 1.5)),
-        None if args[0].type == 'ident' else hue,
+        None if args[2].type == 'ident' else hue,
     ]
     return Color('lch', coordinates, alpha)
 
@@ -372,7 +372,7 @@ def _parse_oklch(args, alpha):
             args[0].value * (1 if args[0].type == 'number' else 0.01)),
         None if args[1].type == 'ident' else (
             args[1].value * (1 if args[1].type == 'number' else 0.004)),
-        None if args[0].type == 'ident' else hue,
+        None if args[2].type == 'ident' else hue,
     ]
     return Color('oklch', coordinates, alpha)