fix color being parsed for none (#312)

Author: cvanelteren

ultraplot/axes/plot.py

@@ -2509,7 +2509,7 @@ def _parse_color(self, x, y, c, *, apply_cycle=True, infer_rgb=False, **kwargs):
         # functions and helper functions.
         parsers = (self._parse_cmap, *self._level_parsers)
         if c is None or mcolors.is_color_like(c):
-            if infer_rgb and c is not None:
+            if infer_rgb and c is not None and c != "none":
                 c = pcolors.to_hex(c)  # avoid scatter() ambiguous color warning
             if apply_cycle:  # False for scatter() so we can wait to get correct 'N'
                 kwargs = self._parse_cycle(**kwargs)

ultraplot/tests/test_plot.py

@@ -420,3 +420,16 @@ def test_pie_labeled_series_in_dataframes():
     for text, index in zip(texts, data.index):
         assert text.get_text() == index
     uplt.close(fig)
+
+
+def test_color_parsing_for_none():
+    """
+    Ensure that none is not parsed to white
+    """
+    fig, ax = uplt.subplots()
+    ax.scatter(0.4, 0.5, 100, fc="none", ec="k", alpha=0.2)
+    ax.scatter(0.5, 0.5, 100, fc="none", ec="k")
+    ax.scatter(0.6, 0.5, 100, fc="none", ec="k", alpha=1)
+    for artist in ax[0].collections:
+        assert artist.get_facecolor().shape[0] == 0
+    uplt.close(fig)