Merge pull request #622 from hchargois/fix-typing

Fix most type hinting issues in library/lcd

library/lcd/color.py

@@ -0,0 +1,47 @@
+from typing import Union, Tuple
+
+from PIL import ImageColor
+
+RGBColor = Tuple[int, int, int]
+
+# Color can be an RGB tuple (RGBColor), or a string in any of these formats:
+# - "r, g, b" (e.g. "255, 0, 0"), as is found in the themes' yaml settings
+# - any of the formats supported by PIL: https://pillow.readthedocs.io/en/stable/reference/ImageColor.html 
+#
+# For example, here are multiple ways to write the pure red color:
+# - (255, 0, 0)
+# - "255, 0, 0"
+# - "#ff0000"
+# - "red"
+# - "hsl(0, 100%, 50%)"
+Color = Union[str, RGBColor]
+
+def parse_color(color: Color) -> RGBColor:
+    # even if undocumented, let's be nice and accept a list in lieu of a tuple
+    if isinstance(color, tuple) or isinstance(color, list):
+        if len(color) != 3:
+            raise ValueError("RGB color must have 3 values")
+        return (int(color[0]), int(color[1]), int(color[2]))
+
+    if not isinstance(color, str):
+        raise ValueError("Color must be either an RGB tuple or a string")
+
+    # Try to parse it as our custom "r, g, b" format
+    rgb = color.split(',')
+    if len(rgb) == 3:
+        r, g, b = rgb
+        try:
+            rgbcolor = (int(r.strip()), int(g.strip()), int(b.strip()))
+        except ValueError:
+            # at least one element can't be converted to int, we continue to
+            # try parsing as a PIL color
+            pass
+        else:
+            return rgbcolor
+
+    # fallback as a PIL color
+    rgbcolor = ImageColor.getrgb(color)
+    if len(rgbcolor) == 4:
+        return (rgbcolor[0], rgbcolor[1], rgbcolor[2])
+    return rgbcolor
+