Add potential fix for X11 using a special selectcolor

daniilS · daniilS · commit 3cc91726a84c · 2022-01-17T11:54:25.000Z
diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -651,9 +651,14 @@ def _set_image_for_button(self, button):
         size = button.winfo_pixels('18p')
 
         # Nested functions because ToolbarTk calls  _Button.
-        def _is_dark(color):
+        def _get_color(color_name):
             # `winfo_rgb` returns an (r, g, b) tuple in the range 0-65535
-            return max(button.winfo_rgb(button.cget(color))) < 65535 / 2
+            return button.winfo_rgb(button.cget(color_name))
+
+        def _is_dark(color):
+            if isinstance(color, str):
+                color = _get_color(color)
+            return max(color) < 65535 / 2
 
         def _recolor_icon(image, color):
             image_data = np.asarray(image).copy()
@@ -683,7 +688,15 @@ def _recolor_icon(image, color):
             isinstance(button, tk.Checkbutton)
             and button.cget("selectcolor") != ""
         ):
-            if _is_dark("selectcolor"):
+            if self._windowingsystem != "x11":
+                selectcolor = "selectcolor"
+            else:
+                # On X11, selectcolor isn't used directly for indicator-less
+                # buttons.
+                r1, g1, b1 = _get_color("selectcolor")
+                r2, g2, b2 = _get_color("activebackground")
+                selectcolor = ((r1+r2)/2, (g1+g2)/2, (b1+b2)/2)
+            if _is_dark(selectcolor):
                 button.configure(selectimage=image_alt)
             else:
                 button.configure(selectimage=image)
