def _get_pixmap_key(image_coords, image_rect, target_rect):
    """Convert params to hashable string.

    :param image_coords: the coordinates of the image center
    :param image_rect: the size of the portion of image to take
    :param target_rect: the size to scale the portion to
    :return: all the parameters combined in one string
    """
    return '{},{},{},{},{},{}'.format(*image_coords, *image_rect, *target_rect)
