Add support of device-cmyk() function

Author: grewn0uille

tinycss2/color4.py

@@ -23,8 +23,10 @@ class Color:
     to [0, 1]. Coordinates can also be set to ``None`` when undefined.
 
     """
+    COLOR_SPACES = COLOR_SPACES
+
     def __init__(self, space, coordinates, alpha):
-        assert space in COLOR_SPACES, f"{space} is not a supported color space"
+        assert space in self.COLOR_SPACES, f"{space} is not a supported color space"
         self.space = space
         self.coordinates = tuple(
             None if coordinate is None else float(coordinate)

tinycss2/color5.py

@@ -0,0 +1,65 @@
+from . import color4
+
+COLOR_SPACES = color4.COLOR_SPACES | {'device-cmyk'}
+D50 = color4.D50
+D65 = color4.D65
+
+
+class Color(color4.Color):
+    COLOR_SPACES = COLOR_SPACES
+
+
+def parse_color(input):
+    color = color4.parse_color(input)
+
+    if color:
+        return color
+
+    if isinstance(input, str):
+        token = parse_one_component_value(input, skip_comments=True)
+    else:
+        token = input
+
+    if token.type == 'function':
+        tokens = [
+            token for token in token.arguments
+            if token.type not in ('whitespace', 'comment')]
+        name = token.lower_name
+        length = len(tokens)
+
+        if length in (7, 9) and all(token == ',' for token in tokens[1::2]):
+            old_syntax = True
+            tokens = tokens[::2]
+        elif length == 4:
+            old_syntax = False
+        elif length == 6 and tokens[4] == '/':
+            tokens.pop(4)
+            old_syntax = False
+        else:
+            return
+        args, alpha = tokens[:4], color4._parse_alpha(tokens[4:])
+
+        if name == 'device-cmyk':
+            return _parse_device_cmyk(args, alpha, old_syntax)
+
+
+def _parse_device_cmyk(args, alpha, old_syntax):
+    """Parse a list of CMYK channels.
+
+    If args is a list of 4 NUMBER or PERCENTAGE tokens, return
+    device-cmyk :class:`Color`. Otherwise, return None.
+
+    Input C, M, Y, K ranges are [0, 1], output are [0, 1].
+
+    """
+    if old_syntax:
+        if color4._types(args) != {'number'}:
+            return
+    else:
+        if color4._types(args) <= {'numbers', 'percentage'}:
+            return
+    cmyk = [
+        arg.value if arg.type == 'number' else
+        arg.value / 100 if arg.type == 'percentage' else None
+        for arg in args]
+    return Color('device-cmyk', cmyk, alpha)