code: def recalc_transforms(self, trcat=None):
          
          if trcat is None:
              trcat = self.trcat
  
          self.tform = {
              'window_to_native': trcat.WindowNativeTransform(self),
              'cartesian_to_window': trcat.CartesianWindowTransform(self),
              'cartesian_to_native': (trcat.RotationTransform(self) +
                                      trcat.CartesianNativeTransform(self)),
              'data_to_cartesian': (trcat.DataCartesianTransform(self) +
                                    trcat.ScaleTransform(self)),
              'data_to_scrollbar': (trcat.DataCartesianTransform(self) +
                                    trcat.RotationTransform(self)),
              'data_to_window': (trcat.DataCartesianTransform(self) +
                                 trcat.ScaleTransform(self) +
                                 trcat.RotationTransform(self) +
                                 trcat.CartesianWindowTransform(self)),
              'data_to_percentage': (trcat.DataCartesianTransform(self) +
                                     trcat.ScaleTransform(self) +
                                     trcat.RotationTransform(self) +
                                     trcat.CartesianWindowTransform(self) +
                                     trcat.WindowPercentageTransform(self)),
              'data_to_native': (trcat.DataCartesianTransform(self) +
                                 trcat.ScaleTransform(self) +
                                 trcat.RotationTransform(self) +
                                 trcat.CartesianNativeTransform(self)),
              'wcs_to_data': trcat.WCSDataTransform(self),
              'wcs_to_native': (trcat.WCSDataTransform(self) +
                                trcat.DataCartesianTransform(self) +
                                trcat.ScaleTransform(self) +
                                trcat.RotationTransform(self) +
                                trcat.CartesianNativeTransform(self)),
          }
docs: Takes a catalog of transforms (`trcat`) and builds the chain
          of default transforms necessary to do rendering with most backends.