'Performs update of the displayed image on the GUI canvas, using the
supplied wx.PaintDC device context.
The \'WXAgg\' backend sets origin accordingly.'

def gui_repaint(self, drawDC=None, origin=u'WX'):

    DEBUG_MSG(u'gui_repaint()', 1, self)
    if self.IsShownOnScreen():
        if (not drawDC):
            drawDC = wx.ClientDC(self)
        if ((wx.Platform == u'__WXMSW__') and (origin == u'WX')):
            img = self.bitmap.ConvertToImage()
            bmp = img.ConvertToBitmap()
            drawDC.DrawBitmap(bmp, 0, 0)
        else:
            drawDC.DrawBitmap(self.bitmap, 0, 0)
