Staves with different numbers of lines / placement of symbols w.r.t. staff lines

[reinierdevalk]

Staves can have fewer (or more?) than six lines.

Example:

phalese-1547_7-no_21.png

[DILewis]

I think we have this already in our spec as <staffdef lines="5"... but I don't know if we can say that symbols go on lines or spaces (and which space)

[reinierdevalk]

@DILewis Ah, you're right. Should I change this issue's title into 'Enable placing symbols on or between staff lines'?

[lpugin]

If I understand correctly, this means that @tab.course in note can be smaller or greater than values indicated in staffDef. So we should allow <note tab.course="0"> (or even <note tab.course="-1">?) for notes below the course / staff lines. Does it make sense?

[DILewis]

@lpugin Not quite. The semantics are constant here, it's just the placement of the symbols – some put put symbols on the lines as if the line is an instrumental course being stopped. Others put the symbol between lines so they're easier to read. If you've got 6 lines, you've got 7 spaces, so there's a choice whether to put the first course above or below the first line.
Does that make sense? Reinier probably has examples to hand.

[lpugin]

Alternatively, we could make some lines invisible. I think this could be indicated in the staffDef/tuning. Something like:

<staffDef lines="6">
  <tuning>
    <course n="1" visible="false"/>
  </tuning>
</staffDef>

However, setting visual parameter in tuning looks pretty wrong, so maybe this should go elsewhere in staffDef. I don't think we have in CNM a way to make one specific staff line invisible.

[reinierdevalk]

I think we should still use the actual course for those notes. Let's say we have a five-line staff, and a note on the sixth course (as in the example in the issue). Then that note should still have tab.course='6', but it might get a ledger staff line.

[lpugin]

OK. I was looking at that particular part:

[reinierdevalk]

@lpugin Yes, that's how I understood you. David is talking about something else: whether the symbols are 'through' the lines (as in your example) or on top of them.

[DILewis]

Sorry, I wasn't thinking about the 5-line staff leger line issue when I replied. Not paying enough attention.

[reinierdevalk]

Should the d on the 6th course in Laurent's example above be treated similar to a note on the 7th, 8th, etc. course, for which there will never be a staff line? EDIT: I mean the diapasons.

[reinierdevalk]

It looks like specifying in the StaffDef whether the symbols are rendered on top of or through the staff lines solves that issue, doesn't it? @lpugin an example of symbols on top of the staff line is this one (notice that there is no ledger line for the 6th-course symbols):

[lpugin]

Actually staffDef@ontheline looks appropriate to make this distinction. For the latest example above I would assume expect:

<staffDef lines="5" ontheline="false"/>

[kepper]

well, @ontheline currently has a slightly different meaning (according to it's description). It determines the placement of notes on a 1-line staff. A value of 'true' places all notes on the line, while a value of 'false' places stems-up notes above the line and stems-down notes below the line. I'm not sure this default placement is sufficient for our use case, but we could model something very similar just for tab, maybe called @ontheline.tab (or some such).

[kepper]

Just to get back to the idea of invisible staff lines above, even though they seem to be less of a solution: There is @lines, but there's also @lines.color (see https://music-encoding.org/guidelines/dev/attribute-classes/att.staffDef.vis.html#attributes_class), which is supposed to get as many values as there are lines, and the documentation explicitly mentions that this may be used to make lines invisible…