Backport PR #23985: Improve rubberband rendering in wx and tk

tacaswell · meeseeksmachine · commit abe4054a4f64 · 2022-10-20T21:56:10.000Z
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 +668,30 @@ 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_black = (
+            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', dash=(3, 3)))
 
     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 +917,7 @@ 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")
diff --git a/lib/matplotlib/backends/backend_wx.py b/lib/matplotlib/backends/backend_wx.py
@@ -508,6 +508,8 @@ def __init__(self, parent, id, figure=None):
         _log.debug("%s - __init__() - bitmap w:%d h:%d", type(self), w, h)
         self._isDrawn = False
         self._rubberband_rect = None
+        self._rubberband_pen_black = wx.Pen('BLACK', 1, wx.PENSTYLE_SHORT_DASH)
+        self._rubberband_pen_white = wx.Pen('WHITE', 1, wx.PENSTYLE_SOLID)
 
         self.Bind(wx.EVT_SIZE, self._on_size)
         self.Bind(wx.EVT_PAINT, self._on_paint)
@@ -625,11 +627,11 @@ def gui_repaint(self, drawDC=None):
         drawDC.DrawBitmap(bmp, 0, 0)
         if self._rubberband_rect is not None:
             # Some versions of wx+python don't support numpy.float64 here.
-            x0, y0, x1, y1 = map(int, self._rubberband_rect)
-            drawDC.DrawLineList(
-                [(x0, y0, x1, y0), (x1, y0, x1, y1),
-                 (x0, y0, x0, y1), (x0, y1, x1, y1)],
-                wx.Pen('BLACK', 1, wx.PENSTYLE_SHORT_DASH))
+            x0, y0, x1, y1 = map(round, self._rubberband_rect)
+            rect = [(x0, y0, x1, y0), (x1, y0, x1, y1),
+                    (x0, y0, x0, y1), (x0, y1, x1, y1)]
+            drawDC.DrawLineList(rect, self._rubberband_pen_white)
+            drawDC.DrawLineList(rect, self._rubberband_pen_black)
 
     filetypes = {
         **FigureCanvasBase.filetypes,
