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