Re: Making an object not take up vertical space?

[Marcus Macauley]

Kieren MacMillan wrote:
> In order to make Lilypond think an object has no horizontal or vertical  
> size, respectively, use
>
>      \once \override ObjectName #'X-extent = #'(0 . 0)
>
> or
>
>      \once \override ObjectName #'Y-extent = #'(0 . 0),
>
> where the \once is optional (as always) and ObjectName is replaced with  
> the actual name of the object (e.g., RehearsalMark or TextScript or...).


P.S. Two things follow from this, the first obvious, the second less  
obvious (at least to me).

First, to make an object take up *some* vertical space, say, 2 staff  
spaces, one can do, e.g.:

\once \override ObjectName #'Y-extent = #'(0 . 2)
or
\once \override ObjectName #'Y-extent = #'(-2 . 0)
or
\once \override ObjectName #'Y-extent = #'(-8 . -6)

The difference between the two numbers, of course, being 2 staff spaces,  
which determines how much vertical space the object will get.

Second, the three examples above result in three different vertical  
positions of the object. In this case, lower numbers cause the object to  
be placed higher (regardless of whether it's above or below the staff).

Thus, it's unnecessary to do both an override Y-extent AND both an  
override extra-offset, if one wants to change both the amount of vertical  
space an object takes up AND shift its vertical position. The two tweaks  
can be combined in the Y-extent pair: the difference between the numbers  
represents the amount of vertical space the object takes up, and the value  
of the numbers inversely affects their position (i.e., as the numbers  
increase, the object moves down).

Marcus