Handle analogous sets of undefined color components in carryforward

coloraide/__meta__.py

@@ -204,5 +204,5 @@ def parse_version(ver: str) -> Version:
     return Version(major, minor, micro, release, pre, post, dev)
 
 
-__version_info__ = Version(8, 8, 1, "final")
+__version_info__ = Version(8, 9, 0, "final")
 __version__ = __version_info__._get_canonical()

coloraide/interpolate/__init__.py

@@ -829,6 +829,9 @@ def carryforward_convert(color: Color, space: str, hue_index: int, powerless: bo
             'L': False, 'V': False, 'a': False, 'b': False
         }
 
+        # Analogous components: all undefined
+        all_undefined = all(math.isnan(c) for c in color[:-1])
+
         # Gather undefined channels
         if isinstance(cs1, RGBish):
             for i, name in zip(cs1.indexes(), ('R', 'G', 'B')):
@@ -838,18 +841,34 @@ def carryforward_convert(color: Color, space: str, hue_index: int, powerless: bo
             for i, name in zip(cs1.indexes(), ('L', 'C', 'H')):
                 if math.isnan(color[i]):
                     channels[name] = True
+            # Analogous components: chroma and hue
+            if channels['C'] and channels['H']:
+                channels['a'] = True
+                channels['b'] = True
         elif isinstance(cs1, Labish):
             for i, name in zip(cs1.indexes(), ('L', 'a', 'b')):
                 if math.isnan(color[i]):
                     channels[name] = True
+            # Analogous components: chroma and hue
+            if channels['a'] and channels['b']:
+                channels['C'] = True
+                channels['H'] = True
         elif isinstance(cs1, HSLish):
             for i, name in zip(cs1.indexes(), ('H', 'C', 'L')):
                 if math.isnan(color[i]):
                     channels[name] = True
+            # Analogous components: chroma and hue
+            if channels['C'] and channels['H']:
+                channels['a'] = True
+                channels['b'] = True
         elif isinstance(cs1, HSVish):
             for i, name in zip(cs1.indexes(), ('H', 'C', 'V')):
                 if math.isnan(color[i]):
                     channels[name] = True
+            # Analogous components: chroma and hue
+            if channels['C'] and channels['H']:
+                channels['a'] = True
+                channels['b'] = True
         elif cs1.is_polar():
             if math.isnan(color[cs1.hue_index()]):  # type: ignore[attr-defined]
                 channels['H'] = True
@@ -859,7 +878,9 @@ def carryforward_convert(color: Color, space: str, hue_index: int, powerless: bo
             carry.append(-1)
 
         # Channels that need to be carried forward
-        if isinstance(cs2, RGBish):
+        if all_undefined:
+            carry.extend(cs2.indexes())
+        elif isinstance(cs2, RGBish):
             indexes = cs2.indexes()
             for e, name in enumerate(('R', 'G', 'B')):
                 if channels[name]:

docs/src/markdown/about/changelog.md

@@ -3,6 +3,10 @@ icon: lucide/scroll-text
 ---
 # Changelog
 
+## 8.9
+
+-   **NEW**: Add support for CSS analogous component sets in interpolation and mixing.
+
 ## 8.8.1
 
 -   **ENHANCE**: Minor speed improvements related to chromatic adaptation.

docs/src/markdown/examples/3d_models.html

@@ -1241,7 +1241,7 @@ <h1>ColorAide Color Space Models</h1>
 let colorSpaces = null
 let colorGamuts = null
 let lastModel = null
-let package = 'coloraide-8.8.1-py3-none-any.whl'
+let package = 'coloraide-8.9-py3-none-any.whl'
 const defaultSpace = 'lab'
 const defaultGamut = 'srgb'
 const exceptions = new Set(['hwb', 'ryb', 'ryb-biased'])

docs/src/markdown/examples/colorpicker.html

@@ -421,7 +421,7 @@ <h1>ColorAide Color Picker</h1>
     let pyodide = null
     let webspace = ''
     let initial = 'oklab(0.69 0.13 -0.1 / 0.85)'
-    let package = 'coloraide-8.8.1-py3-none-any.whl'
+    let package = 'coloraide-8.9-py3-none-any.whl'
 
     const base = `${window.location.origin}/${window.location.pathname.split('/')[1]}/playground/`
     package = base + package

docs/src/markdown/interpolation.md

@@ -1323,8 +1323,8 @@ derived from `RGBish`, so `x`, `y`, and `z` is treated like super saturated `r`,
 Space\ Type  | Channel\ Equivalents
 ------------ | --------
 `RGBish`     | `r`, `g`, `b`
-`LABish`     | `l`
-`LCHish`     | `l`, `c`, `h`
+`Labish`     | `l`
+`LChish`     | `l`, `c`, `h`
 `HSLish`     | `h`, `s`, `l`
 `HSVish`     | `h`, `s`, `v`
 `Cylindrical`| `h`
@@ -1343,6 +1343,11 @@ Opponent a   | `a`
 Opponent b   | `b`
 Value        | `v`
 
+Additionally, `carryforward` is applied to analogous sets as well. This means that a combination of components are
+considered equivalent to another set of components. For instance, if an `LChish` space has an undefined chroma and hue,
+when converting to a `Labish` space, `a` and `b` would be considered undefined (and vice versa). If all color components
+are undefined, then when converted, all components in the new space would also be undefined.
+
 ## Powerless Hues
 
 > [!example] Experimental

docs/src/zensical.yml

@@ -354,7 +354,7 @@ extra_javascript:
   - assets/pymdownx-extras/extra-loader-Ccztcqfq.js
   - https://cdn.jsdelivr.net/npm/ace-builds@1.43.0/src-min-noconflict/ace.js
   - https://cdn.jsdelivr.net/npm/mermaid@11.12.1/dist/mermaid.min.js
-  - playground-config-3ba60a2e.js
+  - playground-config-7363a2a9.js
   - https://cdn.jsdelivr.net/pyodide/v0.29.0/full/pyodide.js
   - assets/coloraide-extras/extra-notebook.js
   - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js

docs/theme/playground-config-3ba60a2e.js → docs/theme/playground-config-7363a2a9.js

@@ -1,5 +1,5 @@
 var colorNotebook = {
-    "playgroundWheels": ['micropip', 'pygments-2.19.2-py3-none-any.whl', 'coloraide-8.8.1-py3-none-any.whl'],
-    "notebookWheels": ['pyyaml', 'markdown-3.10.1-py3-none-any.whl', 'pymdown_extensions-10.20-py3-none-any.whl', 'micropip', 'pygments-2.19.2-py3-none-any.whl', 'coloraide-8.8.1-py3-none-any.whl'],
+    "playgroundWheels": ['micropip', 'pygments-2.19.2-py3-none-any.whl', 'coloraide-8.9-py3-none-any.whl'],
+    "notebookWheels": ['pyyaml', 'markdown-3.10.1-py3-none-any.whl', 'pymdown_extensions-10.20-py3-none-any.whl', 'micropip', 'pygments-2.19.2-py3-none-any.whl', 'coloraide-8.9-py3-none-any.whl'],
     "defaultPlayground": "import coloraide\ncoloraide.__version__\nColor('red')"
 }

tests/test_interpolation.py

@@ -2457,3 +2457,34 @@ def test_spectral_no_colors(self):
 
         with self.assertRaises(ValueError):
             Color.weighted_mix([], method='spectral')
+
+    def test_carryforward_sets(self):
+        """Test analogous sets."""
+
+        result = Color.interpolate(
+            ['color(srgb none none none)', 'oklch(70% 0.1 240)'],
+            space='oklch',
+            carryforward=True
+        )(0.5)
+        self.assertColorEqual(result, Color('oklch(0.7 0.1 240)'))
+
+        result = Color.interpolate(
+            ['oklab(40% none none)', 'oklch(70% 0.1 240)'],
+            space='oklch',
+            carryforward=True
+        )(0.5)
+        self.assertColorEqual(result, Color('oklch(0.55 0.1 240)'))
+
+        result = Color.interpolate(
+            ['oklch(40% none none)', 'oklab(70% 0.1 -1.5)'],
+            space='oklab',
+            carryforward=True
+        )(0.5)
+        self.assertColorEqual(result, Color('oklab(0.55 0.1 -1.5)'))
+
+        result = Color.interpolate(
+            ['hsl(none none 40%)', 'oklab(70% 0.1 -1.5)'],
+            space='oklab',
+            carryforward=True
+        )(0.5)
+        self.assertColorEqual(result, Color('oklab(0.60514 0.1 -1.5)'))

zensical.yml

@@ -354,7 +354,7 @@ extra_javascript:
   - assets/pymdownx-extras/extra-loader-Ccztcqfq.js
   - https://cdn.jsdelivr.net/npm/ace-builds@1.43.0/src-min-noconflict/ace.js
   - https://cdn.jsdelivr.net/npm/mermaid@11.12.1/dist/mermaid.min.js
-  - playground-config-3ba60a2e.js
+  - playground-config-7363a2a9.js
   - https://cdn.jsdelivr.net/pyodide/v0.29.0/full/pyodide.js
   - assets/coloraide-extras/extra-notebook-CU9d9Z53.js
   - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js