ScaledTextField

class ScaledTextField (TextField):
    """A TextField which automatically scales down its font size until the right bound
        no longer overlaps with the `reference` layer's left bound."""

    def execute(self):
        super().execute()

        # Scale down the text layer until it doesn't overlap with a reference layer
        if self.reference:
            scale_text_right_overlap(self.layer, self.reference)