Hi Jim,
On Mon, Apr 27, 2015 at 3:55 PM, Jim Long <lilyp...@umpquanet.com> wrote:
> On Mon, Apr 27, 2015 at 04:44:52PM +0200, Urs Liska wrote:
> >
> > What we have in Frescobaldi depends on what we can "catch" by either
> > listening through engravers or by redefining command. So far I haven't
> > found a notion of a grob knowing if it has been tweaked or not.
>
> As a Scheme/Lilypond novice sitting on the sidelines, I have a
> difficult time judging whether my comments are obvious, stupid,
> trival, useless, impractical, or some exquisite combination of all
> five, but .... (oh, and there's "poorly thought-out")
>
Not at all !
>
> If the grob doesn't know whether it's been tweaked, then perhaps
> \tweak could do it?
Of course, if a grob could know that it's been tweaked--info stored in a
new property 'tweaked--then it would be a simple matter harvesting them.
> Or, perhaps one could create a wrapper directive
> \ctweak which invokes \tweak to perform the specific tweak that was
> requested, and then \ctweak could also color the grob that got
> tweaked? Having to change one's code from tweak to ctweak and back
> may be less than ideal. Perhaps a global variable (ugh) could be
> used by \ctweak, defaulting to black, so that by default \tweak
> and \ctweak are equivalent, except that a user of \ctweak could
> alter the global color variable to something other than black,
> resulting in all the \ctweaks appearing in that color.
>
Sure you could do something like this sketch which handles [\once]
\override and \revert:
:
\version "2.19"
override-color = #red
show-colors = ##t
coverride =
#(define-music-function (parser location arg value)
(symbol-list-or-symbol? scheme?)
(if show-colors
(let* ((path-len (length arg))
(context (if (= path-len 3) (car arg) '()))
(grob (if (null? context) (car arg) (cadr arg)))
(color-path (if (null? context)
(list grob 'color)
(list context grob 'color))))
#{
\override #color-path = #override-color
\override #arg = #value
#})
#{ #}))
crevert =
#(define-music-function (parser location arg)
(symbol-list-or-symbol?)
(if show-colors
(let* ((path-len (length arg))
(context (if (= path-len 3) (car arg) '()))
(grob (if (null? context) (car arg) (cadr arg)))
(color-path (if (null? context)
(list grob 'color)
(list context grob 'color))))
#{
\revert #color-path
\revert #arg
#})
#{ #}))
{
\coverride Stem.thickness 3
c''
\crevert Stem.thickness
c''
\once \coverride Stem.thickness 5
c'
c'
}
(
There's a more sophisticated way to go about getting a grob's "property
path" and checking its validity.)
>
> I can't think offhand how to extend this to support users who use
> a color other than black as the base color for engraved grobs, or
> for how to show tweaked grobs which already use \ctweak's global
> tweak color. But if \tweak is defined in terms of Scheme/Guile
> code (I'm ignorant on that point), perhaps a Scheme guru can
> write a first-order approximation of \ctweak that could be
> included in any project's source code where it is desired.
>
> A deeper change might be to add a property to all grobs that
> contains a tweak-count, initialized to 0. \tweak would increment
> the count of each grob it touches, and then the grobs would know
> whether they've been tweaked or not. Pretty sure this is the
> "obvious" option in paragraph 1.
Sure, or store the property path of the tweak instead of a simple count.
David
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