exactly same as old version

Author: Conengmo

branca/utilities.py

@@ -69,12 +69,17 @@ def linear_gradient(hexList: List[str], nColors: int) -> List[str]:
     input_color_bytes = [
         [int(_hex[i : i + 2], 16) for i in (1, 3, 5)] for _hex in hexList
     ]
-    result = []
-    for output_idx in range(nColors - 1):
-        output_fraction = (len(hexList) - 1) * output_idx / (nColors - 1)
-        idx = int(output_fraction)
-        fraction = output_fraction - idx
-        start, end = input_color_bytes[idx], input_color_bytes[idx + 1]
+    resolution = 765
+    n_indexes = resolution * (len(hexList) - 1)
+    result: List[str] = []
+    for counter in range(nColors - 1):
+        fraction_overall = float(counter) / (nColors - 1)
+        index_overall = int(fraction_overall * (n_indexes - 1))
+        index_color_bin = index_overall % 765
+        idx_input = index_overall // 765
+        fraction = index_color_bin / (resolution - 1)
+        start = input_color_bytes[idx_input]
+        end = input_color_bytes[idx_input + 1]
         new_color_bytes = [int(x + fraction * (y - x)) for x, y in zip(start, end)]
         new_color_hexs = [hex(x)[2:].zfill(2) for x in new_color_bytes]
         result.append("#" + "".join(new_color_hexs))

tests/test_utilities.py

@@ -219,13 +219,4 @@ def test_linear_gradient(
     expected_output: List[str],
 ):
     result = ut.linear_gradient(hex_list, n_colors)
-    assert len(result) == len(expected_output), "Output length mismatch"
-
-    # because we rewrote this function, we allow a difference of 1 between the old and the new version
-    tolerance = 1
-    for actual, expected in zip(result, expected_output):
-        r1, g1, b1 = (int(actual[i : i + 2], 16) for i in (1, 3, 5))
-        r2, g2, b2 = (int(expected[i : i + 2], 16) for i in (1, 3, 5))
-        if not all(abs(a - b) <= tolerance for a, b in zip((r1, g1, b1), (r2, g2, b2))):
-            # to get a nice output, assert the full array when we spot a failure
-            assert result == expected_output
+    assert result == expected_output