+(define-public (bar-line::draw-filled-box x-ext y-ext thickness extent grob)
+ "Return a straight bar-line created by @code{ly:round-filled-box} looking at
+@var{x-ext}, @var{y-ext}, @var{thickness}. The blot is calculated by
+@code{bar-line::calc-blot}, which needs @var{extent} and @var{grob}.
+@var{y-ext} is not necessarily of same value as @var{extent}."
+ (ly:round-filled-box
+ x-ext
+ y-ext
+ (bar-line::calc-blot thickness extent grob)))
+