Re: Keep alive together - call for use cases

On Tue, Aug 16, 2016 at 12:22 PM, Kieren MacMillan [via Lilypond] <[hidden email]> wrote:

Hi Mark,

> I've been working on some patches to enable more flexible uses
> for the Keep_alive_together_engraver.

Thank you!

> if I could ask users for any situations where they can imagine this
> engraver helping, that currently don't work, or don't work easily.

2. The “divisi staves” use-case is also a primary feature/request for me. Similar/analogous use-cases: a two-stave harp part compressing (if necessary) to a single staff in the full score.

I'll just re-state my earlier use-case (in the devel- mailing list) for good measure that extends divisi staves.

Let's say I have a 4-horn group. The way these appear in the score depends on the complexity of their parts, in the following configurations:

1. Each has their own staff

2. They can be grouped into a 1/3 staff and 2/4 staff.

3. They can be grouped together into a single staff.

I imagine them falling into a "keep-alive-tree" like this:

All Horns Group staff

|-- Horns 1/3 Joint Staff

| |

| |-- Horn 1 Staff

| |-- Horn 3 Staff

|-- Horns 2/4 Joint Staff

|-- Horn 2 Staff

|-- Horn 4 Staff

The expected behavior in this (albeit hypothetical) situation would automatically allow for each branch to hide its own higher nodes while allowing the other branches to join together at their highest available node.

For example, say I want to show the Horn 1 part in its own staff. This would FORCE Horn 3 to show up on its own staff, but would ALLOW Horns 2/4 to appear on their joint staff, to get:

- Horn 1 Staff

- Horn 3 Staff

- Horns 2/4 Staff

Alternatively, Horn 3 could jump to the joint staff to minimize the number of extra staves, like:

- Horn 1 Staff

- Horns 2/3/4 Staff

As discussed before, I couldn't find a good way to allow this kind of "nested" divisi functionality because it seemed like the trigger acted more like a global on/off switch. I realize this could really be a coding nightmare, but could be a really helpful feature, too, for automatically splitting/combining frenched staves.

Forgive me if I didn't explain that very well.

Best,

Abraham

From:	tisimst
Subject:	Re: Keep alive together - call for use cases
Date:	Tue, 16 Aug 2016 11:50:34 -0700 (MST)