code: def set_contrast_levels(self, contrast_level=0):
          
          for cmap_panel, img_panel in zip((self.cmap_panels[0], self.cmap_panels[1]),
                                           (self.img1_panel, self.img2_panel)):
              conf = img_panel.conf
              img  = img_panel.conf.data
              if contrast_level is None:
                  contrast_level = 0
              conf.contrast_level = contrast_level
              clevels = [contrast_level, 100.0-contrast_level]
  
              jmin = imin = img.min()
              jmax = imax = img.max()
              cmap_panel.imin_val.SetValue('%.4g' % imin)
              cmap_panel.imax_val.SetValue('%.4g' % imax)
              jmin, jmax = np.percentile(img, clevels)
  
              conf.int_lo[0]  = imin
              conf.int_hi[0]  = imax
              conf.cmap_lo[0] = xlo = (jmin-imin)*conf.cmap_range/(imax-imin)
              conf.cmap_hi[0] = xhi = (jmax-imin)*conf.cmap_range/(imax-imin)
  
              cmap_panel.cmap_hi.SetValue(xhi)
              cmap_panel.cmap_lo.SetValue(xlo)
              cmap_panel.islider_range.SetLabel('Shown: [ %.4g :  %.4g ]' % (jmin, jmax))
              cmap_panel.redraw_cmap()
              img_panel.redraw()
docs: enhance contrast levels, or use full data range
          according to value of self.panel.conf.contrast_level