def rgb_gray_blend():
    frame = wx.Frame(None, title='blend')
    canvas = Canvas(frame, autofit=True)
    canvas.set_img(astronaut())
    canvas.set_cn((0,1,2))
    canvas.set_img(camera(), True)
    canvas.set_cn(0, True)
    canvas.set_mode(0.5)
    frame.Show()
def rgb_test():
    frame = wx.Frame(None, title='gray test')
    canvas = Canvas(frame, autofit=True)
    canvas.set_img(astronaut())
    canvas.set_cn((0,1,2))
    frame.Show()