Re: Staff space size

[Aaron Hill]

On 2021-01-06 6:41 pm, Andrew Bernard wrote:
> If staff height is 20 points, then what is the staff space size? Maybe
> I am overthinking this but suddenly I thought there may be some factor
> of including or not including the staff lines in the measurement. It
> is not immediately apparent to me where staff space is defined in the
> NR.
>
> Somebody help out my overworked brain!
>
> All the best to all for 2021.

If you are open to looking at the code, see 
layout-set-absolute-staff-size-in-module in paper.scm.

The default staff size is indeed 20pt.  For a standard 5-live staff 
symbol, the staff height is 4 staff spaces.  As such, a staff space is 
then by default 5pt.  Note that this is not the actual space between ink 
rather it is the distance between staff lines *on center*.  The actual 
whitespace measurement would then be the staff space less the staff line 
thickness.

Line thickness is computed based on a linear interpolation.  From a 
comment in feta-params.mf, the line thickness measured from reference 
scores was generally 0.5pt irrespective of staff size; however, it was 
determined that smaller staff sizes in LilyPond should use a little less 
ink.  For the default staff space of 5pt, then line thickness is exactly 
0.5pt.  However, as staff space drops to 4.125pt, line thickness should 
only reduce to 0.47pt.


-- Aaron Hill