Re: Add tempo spanners

[Colin Hall]

Xavier Scheuer writes:

> On 4 February 2013 16:01, Kieren MacMillan
> <address@hidden> wrote:
>> Hello all!
>>
>> A few weeks ago, in response to Mike Solomon's call for features and bugs, I 
>> posted a request:
>>
>>>> 2. Allowing a text markup (especially a MetronomeMark) to have a "minimum 
>>>> measure length". This would avoid collisions, particularly where there are 
>>>> lots of multi-measure rests (e.g., orchestral parts).
>>
>> His response was:
>>
>>> #2 is doable via a hack.  Minimum lengths can only work if you use 
>>> spanners, but you can hijack the tempo print function for a text spanner 
>>> (and suppress the line afterwards) and then create a scheme engraver for 
>>> text spanner that uses whatever as the left bound and the next bar line's 
>>> non-musical paper column as the right bound.  Or you could just use the 
>>> existing engraver and use the last note in the measure as a bound, although 
>>> this will potentially create uneven spacing in a measure.
>>>
>>> You'll have to manually put this TextSpanner in the topmost context and/or 
>>> use ly:side-position-interface::move-to-extremal-staff (I'd recommend the 
>>> former, as the latter is powerful but falls in the category of LilyPond 
>>> black magic).  Make sure to use springs and rods and set a minimum-length - 
>>> there's an example in the docs with a hairpin or glissando or something 
>>> spanner-y that does this.
>>
>> Is there anyone out there who can work on this with me? I've got some money 
>> to put towards the implementation.
>
> It would be great to have a TempoTextSpanner, for example in order to
> handle common notation such as
>
>   rit. - - - - a tempo
> or
>   rall - - - -
>
> I do not see this request tracked yet.

Thanks for the report, Xavier, but I think we already have this feature
in Lilypond, don't we? See:

http://lilypond.org/doc/v2.17/Documentation/notation/writing-text#text-spanners

which documents syntax such as:

\override TextSpanner.bound-details.left.text = "rit."
b1\startTextSpan
e,\stopTextSpan

> Bug squad, could you add it?

I'm not clear on what you are proposing. Could you give an example of
the new syntax?

> Maybe Kieren or Mike could give a proper description.

OK, well, if Kieren, Mike or you could propose the syntax then we'll
have a complete feature request and sure, we can add it.

Cheers,
Colin.

-- 
Colin Hall