Test App For Post Close Crash

rect_app.py

#!/usr/bin/env python
import wx


class RectFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        # begin wxGlade: RectFrame.__init__
        kwds["style"] = kwds.get("style", 0) | wx.DEFAULT_FRAME_STYLE
        wx.Frame.__init__(self, *args, **kwds)
        self.draw_panel = wx.Panel(self, wx.ID_ANY)
        self._Buffer = None
        self.path = None
        self.on_size(None)
        self.draw_panel.Bind(wx.EVT_SIZE, self.on_size, self)
        self.draw_panel.Bind(wx.EVT_PAINT, self.on_paint)
        self.draw_panel.Bind(wx.EVT_ERASE_BACKGROUND, self.on_erase)
        self.Bind(wx.EVT_CLOSE, self.on_close, self)
        self.on_update_buffer()

    def on_close(self, event=None):
        if self.path is not None:
            print("Without del self.path it crashes on PC.")
            del self.path
            print("Even with it, crashes on Mac.")
        event.Skip()  # Calls Destroy.

    def on_size(self, event):
        width, height = self.ClientSize
        self._Buffer = wx.Bitmap(width, height)

    def on_erase(self, event):
        pass

    def on_paint(self, event):
        wx.BufferedPaintDC(self.draw_panel, self._Buffer)

    def on_update_buffer(self, event=None):
        dc = wx.MemoryDC()
        dc.SelectObject(self._Buffer)
        dc.Clear()
        dc.SetBackground(wx.WHITE_BRUSH)
        gc = wx.GraphicsContext.Create(dc)
        if self.path is None:
            self.path = wx.GraphicsContext.CreatePath(gc)
            self.path.MoveToPoint(0,0)
            self.path.AddLineToPoint(0,50)
            self.path.AddLineToPoint(50,50)
            self.path.AddLineToPoint(50,0)
        gc.SetPen(wx.BLACK_PEN)
        gc.DrawPath(self.path)
        gc.Destroy()
        del dc

class MyRectApp(wx.App):
    def OnInit(self):
        self.frame = RectFrame(None, wx.ID_ANY, "")
        self.SetTopWindow(self.frame)
        self.frame.Show()
        return True

if __name__ == "__main__":
    example = MyRectApp(0)
    example.MainLoop()