Re: Lining up continuo figures

[Aaron Hill]

On 2020-11-16 1:23 pm, Jon Arnold wrote:
> Wow thanks!
>
> Why does this affect the vertical alignment differently?

I am not an authority as I did not write the code in question, but here 
is how I see the logic of it.

Normally, bass figures would go below the staff, so 
BassFigureAlignmentPlacement.staff-padding gets you a starting vertical 
reference away from the bottom.  Then because figures are stacked 
downward, they layout in a natural fashion moving away from the staff.  
All it generally good here, unless there are staff elements that extend 
below the staff symbol itself in which case an entire stack of figures 
may be pushed further away.

When figures are positioned above the staff, the stacking direction is 
by default still downward.  This makes some sense as it ensures the 
order of figures in the input is still top-down on the page.  The 
problem is that same staff-padding value sets the initial vertical 
reference to be by default only a staff space away from the top.  But 
now each figure is placed *below* this reference point, which will 
almost certainly cause a collision.  As such, the entire stack is pushed 
upward to avoid this.  In some cases, the final vertical alignment 
between neighboring figures may seem to align, but likely it will be 
ragged.

Switching the stacking direction upward allows the figures to move away 
from the staff so the starting vertical reference can be maintained.  
This results in more consistent bottom alignment, though it requires the 
figures to be input a bottom-up order.


-- Aaron Hill