Re: Possible bug(s) with vertical alignment on Dynamics staff

[Peter Toye]

Hi Malte,

Thanks very much for this.I'd not read your comment - I've not had a Lilypond 
Digest yet today so didn't know you'd commented. 

Your answer below is far fuller. My comments are inserted into it.

Sorry for my ignorance - I don't use LP much and this is the first time I've 
had to tweak anything seriously.

Best regards,

Peter
mailto:address@hidden
www.ptoye.com

-------------------------
Friday, August 31, 2018, 2:03:59 PM, Malte Meyn wrote:

> Hi Peter,

> have you read my latest answer on the user list? 
> (https://lists.gnu.org/archive/html/lilypond-user/2018-08/msg00412.html)

> Am 31.08.18 um 13:36 schrieb Peter Toye:
>> 1. Just inserting the text by attaching it to a silent note using "^" or "_" 
>> works as expected. See examples 1 & 2

> I suppose that’s not one of your “possible bugs”, is it? ;)

Err.... No :)> I included them to use as comparisons to the other three.

>> 2. Trying "-" is the same as "_". This isn't documented, and probably 
>> shouldn't be. But it would be useful to have this syntax for horizontally 
>> aligned text. See example 3.

> _ and ^ set the direction property of an Event (in this case a
> TextScriptEvent) to #DOWN and #UP. “-” doesn’t
> set it at all—this means 
> that LilyPond decides whether to set it down or up depending on
> different things (type of grob, voice direction in polyphony, …). Your
> suggestion would mean that “-” sets the
> direction to #CENTER. This isn’t 
> supported at the moment, it’ll throw an error (you can try that:
> \override TextScript.direction = #CENTER).

> Now what should #CENTER behave like? If there
> is some space like in your 
> example, your suggestion is legitimate IMO. But in most cases one has
> only two options, up and down (f. e. think of
> articulations). Letting 
> “-” set the direction to #CENTER, even if
> #CENTER would mean “automatic 
> default behaviour” would be wrong because
> direction information coming 
> from \voiceX commands would be overridden.

In a dynamic staff there aren't engraved notes to attach the text to. My issue 
(which I wasn't 100% clear about) is that dynamics and text are treated 
differently - dynamics ( s2\p ) appear to be centred on the staff (at least, 
they're half-way between the two piano staves) and text is either raised or 
lowered. In this context, #CENTER would have a legitimate meaning. Or are the 
dynamics shifted and the text centered? Not easy to tell.

>> 3. Tweaking the Y-offset by 0.0 using "_" appears to change it to having 
>> used "^" if you see what I mean. Example 4. Tweaking it to -0.6 gives the 
>> result I want. Example 5.

> The Y-offset is calculated (see my answer to 4. below) depending on
> different things including the 'direction
> property. So if you tweak the 
> Y-offset, the direction will be ignored (at
> least for the positioning 
> question).

I didn't know that. Thanks.

>> 4. In the Internals manual, the unit for the Y-offset property is not 
>> mentioned. This wastes a lot of time in experimentation, especially given 
>> issue 3!

> What do you mean by unit? Yes, the IR 
> (http://lilypond.org/doc/v2.19/Documentation/internals/user-backend-properties)
> doesn’t say whether Y-offset is measured in staff-spaces, half
> staff-spaces or some different unit. But I
> suppose you mean “value” 
> here? That value is calculated by a procedure that uses information
> about the context (type of grob, neighbouring
> grobs, font sizes, line 
> breaks, voice direction, …). That’s why the manual cannot give the
> default value as a number—there is no such
> thing as a default value.

I meant the unit (staff-spaces, etc.). Without knowing that, it's not exactly 
easy to work out what value to insert to shift the text by the amount needed. 
Hence my comment on experimentation. Maybe it's a documentation bug.

> I hope I made clear what the problems are here.
> If not, just ask ;) (And 
> have a look at the \offset command I mentioned on the user list :))

You've pointed out the problems, but not of course the answer to my new point 
on number 2.

I shall look at \offset. It's not mentioned in the Learning manual at all. 
Thanks again.

> Cheers,
> Malte

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