code: def create_colormap1d_hot(size=512):
      rgb = np.ones((size, 3), dtype=np.float32)
      hs = size // 2
      u = np.linspace(1, 0, hs)
      rgb[:hs, 0] = 1 - u
      rgb[:hs, 1] = 1 - u
      u = u[::-1]
      rgb[hs:, 1] = 1 - u
      rgb[hs:, 2] = 1 - u
      return rgb
  
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 3 for calling a global function with example usage: create_colormap1d_hot(size) and returns: rgb