code: def activate_zoom(self):
      gloo.set_viewport(0, 0, *self.physical_size)
      self.projection = perspective(
          60.0, self.size[0] / float(self.size[1]), 1.0, 100.0
      )
      self.program["u_projection"] = self.projection
  
file_path: vispy/examples/demo/gloo/terrain.py
imports: from vispy import gloo
  from vispy import app
  from vispy.util.transforms import perspective, translate, rotate
  import numpy
  from scipy.spatial import Delaunay
label_desc: Use image node_id 4 for calling the Canvas obj's underlying member method code with example usage: obj.activate_zoom() without return types