:- module switch_detection_regression.
:- interface.

:- import_module float.

:- type text_align
    --->    start
    ;       end
    ;       left
    ;       right
    ;       center.

:- type direction
    --->    ltr
    ;       rtl.

:- pred halign(text_align::in, direction::in, float::in, float::in,
    float::out) is det.

%---------------------------------------------------------------------------%

:- implementation.

halign(TextAlign, Dir, X0, W, X)  :-
    (
        (
            TextAlign = left
        ;
            TextAlign = start, Dir = ltr
        ;
            TextAlign = end, Dir = rtl
        ),
        X = X0
    ;
        (
            TextAlign = right
        ;
            TextAlign = end, Dir = ltr
        ;
            TextAlign = start, Dir = rtl
        ),
        X = X0 - W
    ;
        TextAlign = center,
        X = X0 - W / 2.0
    ).

%---------------------------------------------------------------------------%