code: def __init__(
      self,
      x=None,
      y=None,
      u=None,
      v=None,
      colormap=None,
      data_lim=None,
      dir_x_right=True,
      dir_y_top=True,
      **kwargs,
  ):
      app.Canvas.__init__(self, **kwargs)
      self.create_shader(colormap)
      self.create_mesh(x, y, u, v)
      self.program.bind(self.vbo)
      if data_lim is not None:
          self._data_lim = data_lim
      else:
          self._data_lim = [[x.min(), x.max()], [y.min(), y.max()]]
      self._dir_x_right = dir_x_right
      self._dir_y_top = dir_y_top
  
      self.activate_zoom()
  
      self.show()
  
file_path: vispy/examples/demo/gloo/unstructured_2d.py
imports: import sys
  import numpy
  import scipy.spatial
  from vispy import gloo, app
  from vispy.util.transforms import ortho
label_desc: Use image node_id 1 to create a new Canvas object from inherited base classes: app with example: obj = Canvas(x, y, u, v, colormap, data_lim, dir_x_right, dir_y_top)