class_docstr: Simple Gaussian filter.
class_docstr_tok: ["Simple","Gaussian","filter","."]
code: def process_image(self, padded_src, dpi):
      tgt_image = np.empty_like(padded_src)
      tgt_image[:, :, :3] = self.color
      tgt_image[:, :, 3] = smooth2d(
          padded_src[:, :, 3] * self.alpha, self.sigma / 72 * dpi
      )
      return tgt_image
  
imports: import matplotlib.pyplot
  import numpy
  from matplotlib.artist import Artist
  import matplotlib.cm
  from matplotlib.colors import LightSource
  import matplotlib.transforms
label_desc: Use image node_id 3 for calling the GaussianFilter obj's underlying member method code with example usage: obj.process_image(padded_src, dpi) and returns: tgt_image