deal with case of int {0, 1}

Author: Conengmo

branca/colormap.py

@@ -56,7 +56,7 @@ def _color_float_to_int(x: float) -> int:
 
 
 def _parse_color(x: Union[tuple, list, str]) -> TypeRGBAFloats:
-    """Convert an unknown color value to an RGBA tuple between 0 and 1."""
+    """Convert an unknown color value to an RGBA tuple of floats between 0 and 1."""
     if isinstance(x, (tuple, list)):
         return _parse_color_as_numerical_sequence(x)
     elif isinstance(x, str) and _is_hex(x):
@@ -71,19 +71,28 @@ def _parse_color(x: Union[tuple, list, str]) -> TypeRGBAFloats:
 
 
 def _parse_color_as_numerical_sequence(x: Union[tuple, list]) -> TypeRGBAFloats:
-    """Convert a color as a sequence of numbers to an RGBA tuple between 0 and 1."""
+    """Convert a color as a sequence of numbers to an RGBA tuple of floats between 0 and 1."""
     if not all(isinstance(value, (int, float)) for value in x):
         raise TypeError("Components in color sequence should all be int or float.")
     if not 3 <= len(x) <= 4:
-        raise ValueError(f"Color sequence should have 3 or 4 elements, not {len(x)}.")
-    conversion_function: Callable = float
-    if 1 < max(x) <= 255:
-        conversion_function = _color_int_to_float
+        raise ValueError(f"Color sequence should have 3 or 4 components, not {len(x)}.")
     if min(x) < 0 or max(x) > 255:
         raise ValueError("Color components should be between 0.0 and 1.0 or 0 and 255.")
+
+    if all(isinstance(value, int) for value in x):
+        # assume integers are a sequence of bytes that have to be normalized
+        conversion_function = _color_int_to_float
+    elif 1 < max(x) <= 255:
+        # values between 1 and 255 are bytes no matter the type and should be normalized
+        conversion_function = _color_int_to_float
+    else:
+        # else assume it's already normalized
+        conversion_function = float
+
     color: List[float] = [conversion_function(value) for value in x]
     if len(color) == 3:
         color.append(1.0)  # add alpha channel
+
     return color[0], color[1], color[2], color[3]
 
 

tests/test_colormap_parse.py

@@ -39,15 +39,26 @@ def test_parse_color(input_data, expected):
 @pytest.mark.parametrize(
     "input_data, expected",
     [
+        # these are byte values as ints and should be normalized and converted
         ((0, 0, 0), (0.0, 0.0, 0.0, 1.0)),
         ((255, 255, 255), (1.0, 1.0, 1.0, 1.0)),
         ((255, 0, 0), (1.0, 0.0, 0.0, 1.0)),
+        # a special case: ints that are 0 or 1 should be considered bytes
+        ((0, 0, 1), (0.0, 0.0, 1 / 255, 1.0)),
+        ((0, 0, 0, 1), (0.0, 0.0, 0.0, 1 / 255)),
+        # these already are normalized floats
         ((0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0)),
+        ((0.0, 0.0, 1.0), (0.0, 0.0, 1.0, 1.0)),
         ((0.5, 0.5, 0.5), (0.5, 0.5, 0.5, 1.0)),
         ((0.1, 0.2, 0.3, 0.4), (0.1, 0.2, 0.3, 0.4)),
         ((0.0, 1.0, 0.0, 0.5), (0.0, 1.0, 0.0, 0.5)),
+        # these are byte values as floats and should be normalized
         ((0, 0, 0, 255.0), (0.0, 0.0, 0.0, 1.0)),
         ((0, 0, 255.0, 0.0), (0.0, 0.0, 1.0, 0.0)),
+        # if floats and ints are mixed, assume they are intended as floats
+        ((0, 0, 1.0), (0.0, 0.0, 1.0, 1.0)),
+        # unless some of them are between 1 and 255
+        ((0, 0, 1.0, 128), (0.0, 0.0, 1 / 255, 128 / 255)),
     ],
 )
 def test_parse_color_as_numerical_sequence(input_data, expected):