code: def ortho(left, right, bottom, top, znear, zfar):
      """Create orthographic projection matrix
  
      Parameters
      ----------
      left : float
          Left coordinate of the field of view.
      right : float
          Right coordinate of the field of view.
      bottom : float
          Bottom coordinate of the field of view.
      top : float
          Top coordinate of the field of view.
      znear : float
          Near coordinate of the field of view.
      zfar : float
          Far coordinate of the field of view.
  
      Returns
      -------
      M : ndarray
          Orthographic projection matrix (4x4).
      """
      assert right != left
      assert bottom != top
      assert znear != zfar
  
      M = np.zeros((4, 4), dtype=np.float32)
      M[0, 0] = +2.0 / (right - left)
      M[3, 0] = -(right + left) / float(right - left)
      M[1, 1] = +2.0 / (top - bottom)
      M[3, 1] = -(top + bottom) / float(top - bottom)
      M[2, 2] = -2.0 / (zfar - znear)
      M[3, 2] = -(zfar + znear) / float(zfar - znear)
      M[3, 3] = 1.0
      return M
  
file_path: vispy/vispy/util/transforms.py
imports: from __future__ import division
  import math
  import numpy
label_desc: Use image node_id 4 for calling a global function with example usage: ortho(left, right, bottom, top, znear, zfar) and returns: M