On Mon, May 4, 2015 at 10:04 PM, David Nalesnik <david.nales...@gmail.com>
wrote:
> Hi Kieren,
>
> On Sat, May 2, 2015 at 6:29 PM, Kieren MacMillan <
> kieren_macmil...@sympatico.ca> wrote:
>
>> Hi David,
>>
>> > > Out of curiosity, do you get results with color-tweaks2.ly (attached
>> somewhere above)?
>> > Same thing: the EE-added tweak gets executed, but doesn’t appear in the
>> log output.
>> > So it doesn't get colored?
>>
>> Sorry… let me be more clear. I \include-d the edition-engraver, and
>> compiled twice: once with an \editionMod to move the [initial] Clef, and
>> once without. The first time, the Clef moved (as expected) and was coloured
>> (as hoped); the second time, the Clef was neither moved nor coloured (both
>> as expected).
>
>
>> HOWEVER, the console output was identical in both cases: the tweak was
>> not recorded in the output (as I thought it should have been?).
>
>
> OK, then the modifying actual grobs approach is proving to be more useful
> on several counts.
>
And it works with that editionEngraver example.
>
> The attached file contains some improvements over color-tweaks2.ly. The
> main difference is that it uses a simple Scheme engraver which must be
> \consists-ed.
>
> \voiceTwo and the like will result in colored objects (stems for example),
> but I don't think there's any help for that. Call it a feature :)
>
oops, forgot the custom color settings.
Anyway, this should do the trick. Let me know how it works out.
Best,
David
%%%%%%%%%%%%%%%%%%%%%%%%%%
override-color = #darkred
tweak-color = #blue
%tweak-color = #override-color
#(define (remove-first symbol alist)
"Remove the first key-value pair of association list @var{alist}
whose key matches @var{symbol}."
(let loop ((alist alist) (result '()))
(cond
((null? alist) result)
((eq? (caar alist) symbol)
(append result (cdr alist)))
(else (loop (cdr alist)
(append result (list (car alist))))))))
#(define (grob::has-default-prop grob prop)
"Check all-grob-descriptions to see if symbol @var{grob} has
a default setting for symbol @var{prop}. Either return the
setting or @code{#f}."
(let ((description (assoc-get grob all-grob-descriptions)))
(if description
(assoc-get 'stencil description))))
#(define (mark-tweak grob)
"Color @var{grob} if it has been tweaked. The color to use is stored
in the global variables @var{override-color} and @var{tweak-color}."
(let* ((default (assoc-get (grob::name grob) all-grob-descriptions))
(props (ly:grob-basic-properties grob))
;; Our procedure has been added to the head of grob's basic
;; properties. Let's not count it as a tweak!
(props
(remove
(lambda (p)
(and (procedure? (cdr p))
(eq? (procedure-name (cdr p)) 'mark-tweak)))
props))
;; We're using after-line-breaking to set color of stencil, but
;; let's preserve its last setting
(after-line-return (assoc-get 'after-line-breaking props))
;; Clef.glyph doesn't appear in all-grob-descriptions, but it
;; is set at some point automatically. Don't mark it unless
;; it genuinely is a user override. There may be other
;; such grobs.
(props
(if (eq? (grob::name grob) 'Clef)
(reverse (remove-first 'glyph (reverse props)))
props))
(diff (lset-difference eq? props default)))
;; Tweaks will not appear in the "basic properties" alist of our grob,
but
;; we can find them through the music event which led to the grob.
This
;; is available through the stream-event which caused our grob.
(if (null? diff)
(let* ((cause (event-cause grob))
(tweaks (and cause
(ly:music-property
(ly:event-property cause 'music-cause)
'tweaks))))
(if (pair? tweaks)
(set! (ly:grob-property grob 'color) tweak-color)))
(set! (ly:grob-property grob 'color) override-color))
;; Return any default setting of after-line-breaking.
after-line-return))
colorTweaksEngraver =
#(lambda (context)
(make-engraver
(acknowledgers
((grob-interface engraver grob source-engraver)
(if (grob::has-default-prop grob 'stencil)
(set! (ly:grob-property grob 'after-line-breaking)
(mark-tweak grob)))))))
[...your music...]
\layout {
\context {
\Score
\consists \colorTweaksEngraver
}
}
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