Merge pull request #25 from facelessuser/feature/overlay-cyl

coloraide/__meta__.py

@@ -188,5 +188,5 @@ def parse_version(ver):
     return Version(major, minor, micro, release, pre, post, dev)
 
 
-__version_info__ = Version(0, 1, 0, "alpha", 7)
+__version_info__ = Version(0, 1, 0, "alpha", 8)
 __version__ = __version_info__._get_canonical()

coloraide/colors/__init__.py

@@ -67,8 +67,8 @@ def __eq__(self, other):
 
         return (
             other.space() == self.space() and
-            other.coords() == self.coords() and
-            other.alpha == self.alpha
+            util.cmp_coords(other.coords(), self.coords()) and
+            util.cmp_coords(other.alpha, self.alpha)
         )
 
     def is_nan(self, name):

coloraide/colors/_interpolate.py

@@ -19,18 +19,21 @@
 from . _range import Angle
 
 
-def overlay(c1, c2, a1, a2, a0):
+def overlay(c1, c2, a1, a2, a0, angle=False):
     """Overlay one color channel over the other."""
 
     if util.is_nan(c1) and util.is_nan(c2):
         return 0.0
     elif util.is_nan(c1):
-        return c2 * a2
+        return c2 if angle else c2 * a2
     elif util.is_nan(c2):
-        return c1 * a1
+        return c1 if angle else c1 * a1
 
-    c0 = c1 * a1 + c2 * a2 * (1 - a1)
-    return c0 / a0 if a0 else c0
+    if angle:
+        return c1 + (c2 - c1) * (1 - a1)
+    else:
+        c0 = c1 * a1 + c2 * a2 * (1 - a1)
+        return c0 / a0 if a0 else c0
 
 
 def interpolate(p, coords1, coords2, create, progress, outspace, premultiplied):
@@ -188,28 +191,26 @@ def overlay(self, background, *, space=None, in_place=False):
             if this is None:
                 raise ValueError('Invalid colorspace value: {}'.format(space))
 
-            # Some spaces, like those that are cylindrical, will not work well,
-            # so a space can specify a rectangular space that is better suited.
-            if this.ALPHA_COMPOSITE is not None:
-                this = this.convert(this.ALPHA_COMPOSITE, fit=True)
-                background = background.convert(background.ALPHA_COMPOSITE, fit=True)
-                if this.space() != background.space():  # pragma: no cover
-                    # Catch the rare event that two spaces request incompatible spaces (maybe some weird
-                    # derived class instance).
-                    raise ValueError('Cannot overlay space {} onto space {}'.format(this.space(), background.space()))
-
             # Get the coordinates and indexes of valid hues
             prepare_coords(this)
             prepare_coords(background)
 
+            # Adjust hues if we have two valid hues
+            if isinstance(this, Cylindrical):
+                adjust_hues(this, background, util.DEF_HUE_ADJ)
+
             coords1 = this.coords()
             coords2 = background.coords()
             a1 = this.alpha
             a2 = background.alpha
             a0 = a1 + a2 * (1.0 - a1)
+            gamut = this._range
             coords = []
+            # Avoid multiplying angles and don't mix them the same as non-angles
             for i, value in enumerate(coords1):
-                coords.append(overlay(coords1[i], coords2[i], a1, a2, a0))
+                g = gamut[i][0]
+                is_angle = isinstance(g, Angle)
+                coords.append(overlay(coords1[i], coords2[i], a1, a2, a0, angle=is_angle))
             this._coords = coords
             this.alpha = a0
         else:

coloraide/colors/_space.py

@@ -77,8 +77,6 @@ class Space(contrast.Contrast, interpolate.Interpolate, distance.Distance, gamut
     GAMUT = None
     # White point
     WHITE = convert.WHITES["D50"]
-    # When doing alpha composition, select an alternative space to perform the compositing in.
-    ALPHA_COMPOSITE = None
 
     def __init__(self, color=None):
         """Initialize."""

coloraide/colors/hsl.py

@@ -63,7 +63,6 @@ class HSL(Cylindrical, Space):
     DEF_VALUE = "color(hsl 0 0 0 / 1)"
     CHANNEL_NAMES = frozenset(["hue", "saturation", "lightness", "alpha"])
     DEFAULT_MATCH = re.compile(RE_DEFAULT_MATCH.format(color_space=SPACE))
-    ALPHA_COMPOSITE = "srgb"
     WHITE = convert.WHITES["D65"]
 
     _range = (

coloraide/colors/hsv.py

@@ -58,7 +58,6 @@ class HSV(Cylindrical, Space):
     CHANNEL_NAMES = frozenset(["hue", "saturation", "value", "alpha"])
     DEFAULT_MATCH = re.compile(RE_DEFAULT_MATCH.format(color_space=SPACE))
     GAMUT = "hsl"
-    ALPHA_COMPOSITE = "srgb"
     WHITE = convert.WHITES["D65"]
 
     _range = (

coloraide/colors/hwb.py

@@ -43,7 +43,6 @@ class HWB(Cylindrical, Space):
     CHANNEL_NAMES = frozenset(["hue", "blackness", "whiteness", "alpha"])
     DEFAULT_MATCH = re.compile(RE_DEFAULT_MATCH.format(color_space=SPACE))
     GAMUT = "hsl"
-    ALPHA_COMPOSITE = "srgb"
     WHITE = convert.WHITES["D65"]
 
     _range = (

coloraide/colors/lch.py

@@ -59,7 +59,6 @@ class LCH(Cylindrical, Space):
     DEF_VALUE = "color(lch 0 0 0 / 1)"
     CHANNEL_NAMES = frozenset(["lightness", "chroma", "hue", "alpha"])
     DEFAULT_MATCH = re.compile(RE_DEFAULT_MATCH.format(color_space=SPACE))
-    ALPHA_COMPOSITE = "lab"
     WHITE = convert.WHITES["D50"]
 
     _range = (

coloraide/util.py

@@ -39,6 +39,15 @@ def no_nan(value):
         return [(0.0 if is_nan(x) else x) for x in value]
 
 
+def cmp_coords(c1, c2):
+    """Compare coordinates."""
+
+    if is_number(c1):
+        return (math.isnan(c1) and math.isnan(c2)) or c1 == c2
+    else:
+        return all(map(lambda a, b: (math.isnan(a) and math.isnan(b)) or a == b, c1, c2))
+
+
 def dot(a, b):
     """Get dot product of simple numbers, vectors, and 2D matrices and/or numbers."""
 

docs/src/markdown/about/changelog.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 0.1.0a8
+
+- **NEW**: Remove workaround to force cylindrical colors to overlay in non-cylindrical spaces. Allow colors to be
+  overlaid in any color space. Original issues related to allowing cylindrical spaces as been fixed. Overlaying in
+  cylindrical spaces may not make sense, but it is no longer prohibited.
+- **FIX**: Ensure color comparison will yield true if two channels have `NaN`.
+
 ## 0.1.0a7
 
 - **FIX**: Fix issue with translation of an input that is compressed hex with a specified alpha.

docs/src/markdown/color.md

@@ -140,7 +140,7 @@ or color names that are part of color variables (`#!css var(--color-red)`).
 import re
 from coloraide import Color
 
-RE_COLOR_START = re.compile(r"(?i)(?:\b(?<![-#&])(?:color|hsla?|lch|lab|hwb|rgba?)\(|\b(?<![-#&])[\w]{3,}(?!\()\b|(?<![&])#)")
+RE_COLOR_START = re.compile(r"(?i)(?:\b(?<![-#&$])(?:color|hsla?|lch|lab|hwb|rgba?)\(|\b(?<![-#&$])[\w]{3,}(?![(-])\b|(?<![&])#)")
 
 text = """Red and yellow are colors. So are #000088 and lch(75% 50 50)."""
 

docs/src/markdown/interpolation.md

@@ -195,10 +195,8 @@ The `overlay` method allows a transparent color to be overlaid on top of another
 two. To perform an overlay, a background color must be provided to the color along with an optional color space. If a
 color is to be overlaid within a smaller color space, the colors will be mapped to the smaller space.
 
-!!! Note "Cylindrical Spaces"
-    Certain color spaces, like cylindrical spaces (HSV, HSL, HWB, and LCH), will not be overlaid in their own space.
-    This is because these spaces do not work well with the overlay algorithm. Instead, such spaces will be mapped to
-    more suitable spaces; such as, HSL, HSV, and HWB to sRGB and LCH to LAB.
+!!! tip "Cylindrical Spaces"
+    It is generally recommended to overlay in non-cylindrical spaces, but there is no limitation to do so.
 
 In the example below, we take the `#!color rgb(100% 0% 0% / 0.5)` and overlay it on the color `#!color black`. This
 yields the color: `#!color rgb(127.5 0 0)`.

tests/test_api.py

@@ -93,3 +93,17 @@ def test_function_set(self):
         c1 = Color('orange')
         c1.set("red", lambda x: x * 0.3)
         self.assertEqual(c1.get("red"), 0.3)
+
+    def test_overlay(self):
+        """Test overlay logic."""
+
+        c1 = Color('blue').set('alpha', 0.5)
+        c2 = Color('yellow')
+        self.assertEqual(c1.overlay(c2), Color('color(srgb 0.5 0.5 0.5)'))
+
+    def test_overlay_cyl(self):
+        """Test overlay logic."""
+
+        c1 = Color('blue').set('alpha', 0.5)
+        c2 = Color('yellow')
+        self.assertEqual(c1.overlay(c2, space="hsl"), Color('color(srgb 0 1 0.5)'))

tools/colors.py

@@ -14,7 +14,7 @@
 AST_BLOCKS = (ast.If, ast.For, ast.While, ast.Try, ast.With, ast.FunctionDef, ast.ClassDef)
 
 RE_COLOR_START = re.compile(
-    r"(?i)(?:\b(?<![-#&])(?:color|hsla?|lch|lab|hwb|rgba?)\(|\b(?<![-#&])[\w]{3,}(?!\()\b|(?<![&])#)"
+    r"(?i)(?:\b(?<![-#&$])(?:color|hsla?|lch|lab|hwb|rgba?)\(|\b(?<![-#&$])[\w]{3,}(?![(-])\b|(?<![&])#)"
 )