Fix rubberband visibility for tk backend

oscargus · oscargus · commit da1ae8a8f9a3 · 2022-09-22T17:05:45.000+02:00
diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -212,7 +212,8 @@ def filter_destroy(event):
 
         self._tkcanvas.focus_set()
 
-        self._rubberband_rect = None
+        self._rubberband_rect_black = None
+        self._rubberband_rect_white = None
 
     def _update_device_pixel_ratio(self, event=None):
         # Tk gives scaling with respect to 72 DPI, but Windows screens are
@@ -667,21 +668,28 @@ def set_message(self, s):
 
     def draw_rubberband(self, event, x0, y0, x1, y1):
         # Block copied from remove_rubberband for backend_tools convenience.
-        if self.canvas._rubberband_rect:
-            self.canvas._tkcanvas.delete(self.canvas._rubberband_rect)
+        if self.canvas._rubberband_rect_white:
+            self.canvas._tkcanvas.delete(self.canvas._rubberband_rect_white)
+        if self.canvas._rubberband_rect_black:
+            self.canvas._tkcanvas.delete(self.canvas._rubberband_rect_black)
         height = self.canvas.figure.bbox.height
         y0 = height - y0
         y1 = height - y1
-        self.canvas._rubberband_rect = self.canvas._tkcanvas.create_rectangle(
-            x0, y0, x1, y1)
+        self.canvas._rubberband_rect_white = self.canvas._tkcanvas.create_rectangle(
+            x0, y0, x1, y1, outline='white')
+        self.canvas._rubberband_rect_black = self.canvas._tkcanvas.create_rectangle(
+            x0, y0, x1, y1, dash=(1, 1))
 
     def remove_rubberband(self):
-        if self.canvas._rubberband_rect:
-            self.canvas._tkcanvas.delete(self.canvas._rubberband_rect)
-            self.canvas._rubberband_rect = None
+        if self.canvas._rubberband_rect_white:
+            self.canvas._tkcanvas.delete(self.canvas._rubberband_rect_white)
+            self.canvas._rubberband_rect_white = None
+        if self.canvas._rubberband_rect_black:
+            self.canvas._tkcanvas.delete(self.canvas._rubberband_rect_black)
+            self.canvas._rubberband_rect_black = None
 
     lastrect = _api.deprecated("3.6")(
-        property(lambda self: self.canvas._rubberband_rect))
+        property(lambda self: self.canvas._rubberband_rect_black))
 
     def _set_image_for_button(self, button):
         """
@@ -907,7 +915,7 @@ def remove_rubberband(self):
             self._make_classic_style_pseudo_toolbar())
 
     lastrect = _api.deprecated("3.6")(
-        property(lambda self: self.figure.canvas._rubberband_rect))
+        property(lambda self: self.figure.canvas._rubberband_rect_black))
 
 
 @_api.deprecated("3.5", alternative="ToolSetCursor")
