Merge pull request #3193 from plotly/fix_sample_colorscale

Fix sample colorscale

Author: nicolaskruchten

packages/python/plotly/_plotly_utils/colors/__init__.py

@@ -831,8 +831,8 @@ def get_colorscale(name):
         raise exceptions.PlotlyError(f"Colorscale {name} is not a built-in scale.")
 
     if should_reverse:
-        return colorscale[::-1]
-    return colorscale
+        colorscale = colorscale[::-1]
+    return make_colorscale(colorscale)
 
 
 def sample_colorscale(colorscale, samplepoints, low=0.0, high=1.0, colortype="rgb"):

packages/python/plotly/plotly/express/colors/__init__.py

@@ -47,4 +47,6 @@
     "plotlyjs",
     "DEFAULT_PLOTLY_COLORS",
     "PLOTLY_SCALES",
+    "get_colorscale",
+    "sample_colorscale",
 ]

packages/python/plotly/plotly/tests/test_core/test_colors/test_colors.py

@@ -152,16 +152,29 @@ def test_get_colorscale(self):
         self.assertRaisesRegex(PlotlyError, pattern, colors.get_colorscale, name)
 
         # test non-capitalised access
-        self.assertEqual(colors.sequential.haline, colors.get_colorscale("haline"))
+        self.assertEqual(
+            colors.make_colorscale(colors.sequential.haline),
+            colors.get_colorscale("haline"),
+        )
         # test capitalised access
-        self.assertEqual(colors.diverging.Earth, colors.get_colorscale("Earth"))
+        self.assertEqual(
+            colors.make_colorscale(colors.diverging.Earth),
+            colors.get_colorscale("Earth"),
+        )
         # test accessing non-capitalised scale with capitalised name
-        self.assertEqual(colors.cyclical.mrybm, colors.get_colorscale("Mrybm"))
+        self.assertEqual(
+            colors.make_colorscale(colors.cyclical.mrybm),
+            colors.get_colorscale("Mrybm"),
+        )
         # test accessing capitalised scale with non-capitalised name
-        self.assertEqual(colors.sequential.Viridis, colors.get_colorscale("viridis"))
+        self.assertEqual(
+            colors.make_colorscale(colors.sequential.Viridis),
+            colors.get_colorscale("viridis"),
+        )
         # test accessing reversed scale
         self.assertEqual(
-            colors.diverging.Portland_r, colors.get_colorscale("portland_r")
+            colors.make_colorscale(colors.diverging.Portland_r),
+            colors.get_colorscale("portland_r"),
         )
 
     def test_sample_colorscale(self):
@@ -194,3 +207,7 @@ def test_sample_colorscale(self):
             defined_colors, samplepoints, colortype="tuple"
         )
         self.assertEqual(expected_output, output)
+
+        self.assertEqual(
+            colors.sample_colorscale("TuRbId_r", 12), colors.sequential.turbid_r,
+        )