Update ColorAide version to one that uses exact CSS HWB algorithm

Author: facelessuser

CHANGES.md

@@ -1,5 +1,10 @@
 # ColorHelper
 
+## 6.3.1
+
+- **FIX**: Update to ColorAide 2.9.1 which uses the exact CSS HWB
+  algorithm instead of the HSV -> HWB algorithm.
+
 ## 6.3.0
 
 - **NEW**: Upgrade to ColorAide 2.9.

lib/coloraide/__meta__.py

@@ -192,5 +192,5 @@ def parse_version(ver: str) -> Version:
     return Version(major, minor, micro, release, pre, post, dev)
 
 
-__version_info__ = Version(2, 9, 0, "final")
+__version_info__ = Version(2, 9, 1, "final", post=1)
 __version__ = __version_info__._get_canonical()

lib/coloraide/average.py

@@ -8,7 +8,13 @@
     from .color import Color
 
 
-def average(create: Type['Color'], colors: Iterable[ColorInput], space: str, premultiplied: bool = True) -> 'Color':
+def average(
+    create: Type['Color'],
+    colors: Iterable[ColorInput],
+    space: str,
+    premultiplied: bool = True,
+    powerless: bool = False
+) -> 'Color':
     """Average a list of colors together."""
 
     obj = create(space, [])
@@ -29,7 +35,7 @@ def average(create: Type['Color'], colors: Iterable[ColorInput], space: str, pre
     for c in colors:
         obj.update(c)
         # If cylindrical color is achromatic, ensure hue is undefined
-        if hue_index >= 0 and not math.isnan(obj[hue_index]) and obj.is_achromatic():
+        if powerless and hue_index >= 0 and not math.isnan(obj[hue_index]) and obj.is_achromatic():
             obj[hue_index] = alg.nan
         coords = obj[:]
         alpha = coords[-1]

lib/coloraide/color.py

@@ -1069,6 +1069,7 @@ def average(
         space: Optional[str] = None,
         out_space: Optional[str] = None,
         premultiplied: bool = True,
+        powerless: Optional[bool] = None,
         **kwargs: Any
     ) -> 'Color':
         """Average the colors."""
@@ -1079,7 +1080,13 @@ def average(
         if out_space is None:
             out_space = space
 
-        return average.average(cls, colors, space, premultiplied).convert(out_space, in_place=True)
+        return average.average(
+            cls,
+            colors,
+            space,
+            premultiplied,
+            powerless if powerless is not None else cls.POWERLESS,
+        ).convert(out_space, in_place=True)
 
     def filter(  # noqa: A003
         self,

lib/coloraide/spaces/hwb/__init__.py

@@ -1,36 +1,30 @@
 """HWB class."""
 from ...spaces import Space, HWBish
+from ..hsl import srgb_to_hsl, hsl_to_srgb
 from ...cat import WHITES
-from ... import util
 from ...channels import Channel, FLG_ANGLE, FLG_OPT_PERCENT
 from ...types import Vector
 
 
-def hwb_to_hsv(hwb: Vector) -> Vector:
-    """HWB to HSV."""
+def srgb_to_hwb(srgb: Vector) -> Vector:
+    """HWB to sRGB."""
 
-    h, w, b = hwb
-
-    wb = w + b
-    if wb >= 1:
-        return [h, 0.0, w / wb]
-
-    v = 1 - b
-    s = 0 if v == 0 else 1 - w / v
-    return [util.constrain_hue(h), s, v]
+    return [srgb_to_hsl(srgb)[0], min(srgb), 1 - max(srgb)]
 
 
-def hsv_to_hwb(hsv: Vector) -> Vector:
-    """HSV to HWB."""
+def hwb_to_srgb(hwb: Vector) -> Vector:
+    """HWB to sRGB."""
 
-    h, s, v = hsv
-    return [util.constrain_hue(h), v * (1 - s), 1 - v]
+    h, w, b = hwb
+    wb_sum = w + b
+    wb_factor = 1 - w - b
+    return [w / wb_sum] * 3 if wb_sum >= 1 else [c * wb_factor + w for c in hsl_to_srgb([h, 1, 0.5])]
 
 
 class HWB(HWBish, Space):
     """HWB class."""
 
-    BASE = "hsv"
+    BASE = "srgb"
     NAME = "hwb"
     SERIALIZE = ("--hwb",)
     CHANNELS = (
@@ -49,19 +43,14 @@ class HWB(HWBish, Space):
     def is_achromatic(self, coords: Vector) -> bool:
         """Check if color is achromatic."""
 
-        if (coords[1] + coords[2]) >= (1 - 1e-07):
-            return True
-
-        v = 1 - coords[2]
-        s = 0 if v == 0 else 1 - coords[1] / v
-        return abs(s) < 1e-4
+        return (coords[1] + coords[2]) >= (1 - 1e-07)
 
     def to_base(self, coords: Vector) -> Vector:
-        """To HSV from HWB."""
+        """To sRGB from HWB."""
 
-        return hwb_to_hsv(coords)
+        return hwb_to_srgb(coords)
 
     def from_base(self, coords: Vector) -> Vector:
-        """From HSV to HWB."""
+        """From sRGB to HWB."""
 
-        return hsv_to_hwb(coords)
+        return srgb_to_hwb(coords)

support.py

@@ -5,7 +5,7 @@
 import webbrowser
 import re
 
-__version__ = "6.3.0"
+__version__ = "6.3.1"
 __pc_name__ = 'ColorHelper'
 
 CSS = '''