def to_dynamic_cwd_tuple(x):
    """Convert to a canonical cwd_width tuple."""
    unit = 'c'
    if isinstance(x, str):
        if x[-1] == '%':
            x = x[:-1]
            unit = '%'
        else:
            unit = 'c'
        return float(x), unit
    else:
        return float(x[0]), x[1]
