From e14c796888733ab3c9caf43019663b8a06cb11ba Mon Sep 17 00:00:00 2001
From: Alek Ratzloff <alekratz@gmail.com>
Date: Fri, 24 May 2024 11:45:23 -0700
Subject: [PATCH] Split out color palettes to their own file

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>
---
 colorhash/__main__.py | 16 +++----------
 colorhash/palettes.py | 56 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 13 deletions(-)
 create mode 100644 colorhash/palettes.py

diff --git a/colorhash/__main__.py b/colorhash/__main__.py
index 0fa6437..06b05c2 100644
--- a/colorhash/__main__.py
+++ b/colorhash/__main__.py
@@ -7,24 +7,14 @@ import sys
 
 from .colorizer import PaletteColorizer
 from .matricizer import Matricizer, NibbleMatricizer, RandomartMatricizer
+from .palettes import DEFAULT_PALETTES, PALETTES
 from .svg import gensvg
 
 
 # TODO - WASM compile for embedding directly in HTML
 # TODO - option to add a caption based on the filename
-# TODO - palettes defined by JSON
-
-
-PALETTES = {
-    "red": [f"#{0x110000 * i:06x}" for i in range(0x10)],
-    "green": [f"#{0x001100 * i:06x}" for i in range(0x10)],
-    "blue": [f"#{0x000011 * i:06x}" for i in range(0x10)],
-    "black": [f"#{0x111111 * i:06x}" for i in range(0x10)],
-    "cyan": [f"#{0x001111 * i:06x}" for i in range(0x10)],
-    "yellow": [f"#{0x111100 * i:06x}" for i in range(0x10)],
-    "magenta": [f"#{0x110011 * i:06x}" for i in range(0x10)],
-    "white": [f"#{0x111111 * (0xF - i):06x}" for i in range(0x10)],
-}
+# TODO - load palettes from a file
+# TODO - HSV color
 
 
 def main() -> None:
diff --git a/colorhash/palettes.py b/colorhash/palettes.py
new file mode 100644
index 0000000..e364ed5
--- /dev/null
+++ b/colorhash/palettes.py
@@ -0,0 +1,56 @@
+"Base color palette definitions."
+import abc
+from typing import Sequence, Self
+
+
+class Palette(metaclass=abc.ABCMeta):
+    """
+    A 16-color palette.
+
+    All colors must be HTML color strings.
+    """
+
+    @abc.abstractmethod
+    def choose(self, color: int) -> str:
+        """
+        Chooses the given color in this palette.
+        """
+
+    def __getitem__(self, color: int) -> str:
+        return self.choose(color)
+
+
+class StaticPalette(Palette):
+    """
+    A static color palette with discrete colors.
+    """
+
+    def __init__(self, colors: Sequence[str]) -> None:
+        """
+        Creates a new static color palette.
+
+        :param colors: the colors for this palette. Must be exactly 16 colors.
+        """
+        if len(colors) != 16:
+            raise ValueError(f"palette must have exactly 16 colors (got {len(colors)})")
+        self.colors = colors
+
+    def choose(self, color: int) -> str:
+        if not isinstance(color, int):
+            raise KeyError("palette color indices must be an integer")
+        return self.colors[color]
+
+
+DEFAULT_PALETTES = {
+    "red": StaticPalette([f"#{0x110000 * i:06x}" for i in range(0x10)]),
+    "green": StaticPalette([f"#{0x001100 * i:06x}" for i in range(0x10)]),
+    "blue": StaticPalette([f"#{0x000011 * i:06x}" for i in range(0x10)]),
+    "black": StaticPalette([f"#{0x111111 * i:06x}" for i in range(0x10)]),
+    "cyan": StaticPalette([f"#{0x001111 * i:06x}" for i in range(0x10)]),
+    "yellow": StaticPalette([f"#{0x111100 * i:06x}" for i in range(0x10)]),
+    "magenta": StaticPalette([f"#{0x110011 * i:06x}" for i in range(0x10)]),
+    "white": StaticPalette([f"#{0x111111 * (0xF - i):06x}" for i in range(0x10)]),
+}
+
+
+PALETTES = {**DEFAULT_PALETTES}