How does manual note spacing really work?

[dspreadbury]

@dankreider

1. I see Ctrl-Alt-arrow is equivalent to Alt-arrow x 8. But sometimes the resultant change is larger than other times. How is that bit calculated?

Ctrl+Alt+arrow always moves the selected handle by one space, but because horizontal justification across the whole width of the system is always playing its part, depending on how you expand the size of one column, the effect of justification on other columns may cause a gap to appear larger or smaller.

@dankreider

2. What are the values underneath the percentage in the right-side box?

They are spaces. The denominator of the fraction is the total number of spaces from the beginning of “rhythmic space”, i.e. immediately to the right of whatever is the rightmost item in the preamble (normally the key signature), to the right-hand end of the system. The numerator of the fraction is the number of “occupied” spaces, i.e. the solid space for each column, which takes into account any adjustment you have made to the square handles (this gets added on to the solid space for the column). The difference between the two is the amount of space that is justified out across the whole system to make the music reach the right-hand side of the frame.

@dankreider

3. When I make a spacing change at one location, where in the system is Dorico pulling from? Is it proportionately from all other spacing locations? Or does it affect other columns more or less depending on their distance from the column being modified?

When you make a column wider, you are changing the overall amount of “solid” space in the system, i.e. you are changing the numerator of the fraction that appears in the system fullness indicator. You are therefore reducing the amount of justified space, so you are effectively taking the space away from all other columns in the system. You can indirectly return the space back to the pool to be used for justification by making corresponding opposite adjustments to other columns, i.e. reducing the overall amount of “solid” space.

@dankreider

4. When I modify a column, turning its handle red, and then modify another column, how is that first column modified differently than before? Is it still proportionately added to or subtracted from?

Adjustments made to each column are completely independent. Changing the solid space for one column does not cause the solid space required for any other column to change. All columns are justified in the same way, regardless of whether they have been edited. (What I cannot remember off the top of my head is whether or not justification takes into account the rhythmic length for each column in order to allocate more space to longer durations; certainly this was what we planned, but since it’s been a few years since we actually implemented it, I cannot remember.)