code: def apply_zoom(self):
      width, height = self.physical_size
      gloo.set_viewport(0, 0, width, height)
      self.program["resolution"] = [width, height]
  
file_path: vispy/examples/demo/gloo/mandelbrot.py
imports: from vispy import app, gloo
label_desc: Use image node_id 4 for calling the Canvas obj's underlying member method code with example usage: obj.apply_zoom() without return types