def __init__(self, full_alpha_values, unit_alpha_values):
        """Store alpha values and define size."""
        ### store both lists of lists representing alpha
        ### values in different formats

        self.full_alpha_values = full_alpha_values
        self.unit_alpha_values = unit_alpha_values

        ### store size
        self.size = size_from_alpha_values(full_alpha_values)

        ### store a bounding rect representing the area
        ### occupied by the alpha values different from 0;

        ## XXX profiling note: this should be pretty quick;
        ## would it be quicker though if we calculate this
        ## ourselves?
        self.bounding_rect = self.get_colored_surface((0, 0, 0)).get_bounding_rect()
Store alpha values and define size.
nodezator/alphamask/main.py