Custom wxPython control

customcontrol.py

import wx


class CustomPanel(wx.PyPanel):

    def __init__(self, parent):
        wx.PyPanel.__init__(self, parent)

        self.Bind(wx.EVT_PAINT, self.OnPaint)
        self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)

    def DoGetBestSize(self):
        # tells the sizer the ideal dimensions
        return wx.Size(300, 300)

    def OnPaint(self, event):
        # Double buffer to avoid flickering
        dc = wx.BufferedPaintDC(self)

        width, height = self.GetClientSize()

        backBrush = wx.Brush("red", wx.SOLID)
        dc.SetBackground(backBrush)

        dc.SetPen(wx.Pen("black"))
        dc.SetBrush(wx.Brush("green"))

        dc.Clear()
        dc.DrawPolygon([
            (5,5),
            (80,5),
            (80,80),
            (5,80)
            ])

        dc.DrawRectangle(100,100,150,150)

    def OnEraseBackground(self, event):
        # Background gets drawn in OnPaint with a double 
        # buffer to avoid flickering
        pass
        

def main():
    app = wx.App()
    frame = wx.Frame(None)
    custom = CustomPanel(frame)

    sizer = wx.BoxSizer()
    sizer.Add(custom, 0)

    frame.SetSizer(sizer)
    frame.Show()

    app.MainLoop()


if __name__ == "__main__":
    main()