fix: name2color() colororder reordering returns list, not ndarray

src/machinevisiontoolbox/base/color.py

@@ -815,8 +815,10 @@ def csconvert(name: str, cs: str) -> np.ndarray:
                 color = (color * np.iinfo(dtype).max).astype(dtype)
             if colororder is not None:
                 # reorder the elements of the color if colororder is given
-                # colororder is a dict mapping plane name to index
-                color = [color[colororder[c]] for c in colorspace]
+                # colororder is a dict mapping plane name to index -- fancy
+                # index rather than a list comprehension, to keep the
+                # ndarray return type promised by this function's contract
+                color = color[[colororder[c] for c in colorspace]]
             return color
         except ValueError:
             return None

tests/base/test_base_color.py

@@ -145,7 +145,20 @@ def test_name2color(self):
         # Test different color spaces
         g_xy = color.name2color('g', 'xy')
         self.assertEqual(len(g_xy), 2)
-
+
+    def test_name2color_colororder(self):
+        """colororder= must still return an ndarray, not a list -- regression
+        test for a bug where the reordering used a list comprehension and
+        silently dropped the ndarray return type"""
+        red_rgb = color.name2color('red', colororder={'R': 0, 'G': 1, 'B': 2})
+        self.assertIsInstance(red_rgb, np.ndarray)
+        nt.assert_array_almost_equal(red_rgb, [1, 0, 0])
+
+        # reordered: B first, so red's 1.0 moves to the last position
+        red_bgr = color.name2color('red', colororder={'B': 0, 'G': 1, 'R': 2})
+        self.assertIsInstance(red_bgr, np.ndarray)
+        nt.assert_array_almost_equal(red_bgr, [0, 0, 1])
+
     def test_colorname(self):
         """Test color to name conversion"""
         # Test basic lookup

tests/test_image_point_features.py

@@ -197,6 +197,18 @@ def test_corners(self):
         except:
             pass
 
+    def test_draw2(self):
+        """draw2() with a named color and a colorized (colororder-bearing)
+        image must not raise -- regression test for name2color() leaking a
+        plain list instead of an ndarray when colororder is given"""
+        img = Image.Read("monalisa.png", mono=True)
+        orb = img.ORB(nfeatures=20)
+        self.assertGreater(len(orb), 0)
+
+        color_img = img.colorize()
+        result = orb.draw2(color_img, color="y")
+        self.assertIsInstance(result, Image)
+
     def test_features_list_operations(self):
         """Test feature list operations"""
         img = Image.Read("monalisa.png", mono=True)