Re: [Denemo-devel] A Good Idea

[Richard Shann]

I realized that I don't need much to implement this. Here is a script
which goes thru the current staff, running (L-<tag>) for any directives
it finds. It doesn't even check if it should, but it correctly updates
the Anacrusis if you have changed the duration of the upbeat.
 
(d-GoToBeginning)
 
(define (L-Anacrusis)
  (d-Anacrusis))
 
(let loop ((tag #f))
 (set! tag (d-DirectiveGetTag-standalone))
 (if (string? tag)
     (eval-string (string-append "(L-" tag ")")))
 (if (d-NextStandaloneDirective)
     (loop tag)))
     
My immediate interest is multi measure rests...

Richard


On Sat, 2009-11-07 at 10:21 +0000, Richard Shann wrote:
> I have just posted these thoughts at
> http://denemo.org/index.php/Dynamic_Denemo_Directives
> 
> Dynamic Denemo Directives
> 
> 
> The current DenemoDirectives are created by commands invoked by the user
> while creating the musical score. However there are many circumstances
> where the directive needs to be modified for some condition that is
> pertaining at print or play time. For example, when printing parts the
> font size may need to be larger than when printing a score.
> 
> This design allows any directive to have a flag set in its override
> field to indicate that a procedure (named from its tag) should be run
> before printing or playing the score. Such a procedure could consult
> conditions that have been given a value by the user and modify the
> LilyPond or MIDI output to suit. It could also check, for example, if
> the music had been edited since the directive was originally installed,
> which may require the directive to be modified. Other tasks could
> include installing the repeat open directive to match first and secont
> time bars. Here is the detailed design:
> 
> When creating LilyPond output or MIDI output, we could invoke a
> procedure (L-<tag>) or (M-tag) for all directives that have the <tag>
> and the override flag DYNAMIC_LILYPOND or DYNAMIC_MIDI set. That is, if
> you want a directive to run a script at print or play time you set the
> override and, provided M/L-<tag> exists it will be run. If (defined?
> `M/L-<tag>) is #f it would try to load the procedure from disk
> (actions/lilyscripts/tag or actions/midiscripts/tag). 
> 
> The new infrastructure would be in exportmidi.c and exportlilypond.c, it would
>      * store the cursor position (current movement, staff, measure and object 
> as numerical positions, not pointers)
>      * move the cursor through the whole score
>      * examine all directives for the appropriate DYNAMIC_xxx override
>      * if set, execute the script L-<tag> or M-<tag>, getting it from disk if 
> not defined.
>      * restore the cursor
>      
> 
> Applications:
> 
>      * Anacrusis/upbeat/pickup the procedure L-Anacrusis just runs 
> (d-Anacrusis) which will update the LilyPond to match the duration of the 
> upbeat actually present
>      * Multi-Measure rests, the script steps forward stopping when it 
> encounters timesig changes, rehearsal marks, music etc. For each whole 
> measure rest it encounters, it increments a counter and removes the LilyPond 
> output for it, placing the cumulative multi-measure rest in the directive 
> that is running the script.
>      * Crescendo: the procedure M-Crescendo steps forward looking for the end 
> crescendo. It takes start and end volumes from these two directives (or else 
> some default) and computes a volume increase per second. Then it sets the 
> midi volume on each chord according to its timing by setting a directive on 
> the chords.
>      
> 
> (1) The thing being that you cannot put the lily/midiscripts in
> init.scm, since the command generating the directive will not have been
> run in general during this invocation of Denemo.
> 
> 
> 
> 
> 
> 
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