2018-01-30 6:19 GMT+01:00 Michael Winter <mwin...@unboundedpress.org>:
> A bit more here. I think I can fake this in a markup... See example pasted
> below. My scheme skilz are minimal. I would like yo do this interpolating
> between the x position of adjacent notes. So maybe I can do this as a custom
> beam stencil. or some kind of spanner. Basically I want a scheme function
> that will give me the position of a given note and the next note... Thanks!
>
> \relative c'' {
> s64
> -\markup {
> \combine
> \override #'(line-join-style . miter)
> \with-color #(x11-color 'grey60)
> \path #2
> #'((moveto 0 0)
> (lineto 0.3 0)
> (closepath)
> )
>
> \combine
> \override #'(line-join-style . miter)
> \with-color #(x11-color 'grey40)
> \path #2
> #'((moveto 0.3 0)
> (lineto 0.6 0)
> (closepath))
>
> \override #'(line-join-style . miter)
> \with-color #(x11-color 'grey20)
> \path #2
> #'((moveto 0.6 0)
> (lineto 0.9 0)
> (closepath))
>
> }
>
>
> }
>
>
> On 01/29/2018 06:27 PM, Michael Winter wrote:
>>
>> Hello...
>>
>> I have tried quite a few hacks, but nothing really suitable.
>>
>> What I really want is to simple draw a line beneath the staff that has a
>> grey scale gradient such that for each note, I give a target value.
>>
>> Most of what I have tried involves doing this in increments with
>> overlapping spanners, I also tried the code in this thread:
>> https://lists.nongnu.org/archive/html/lilypond-user/2016-10/msg00097.html
>>
>> I think the answer is doing this with svg directives since in the svg
>> documentation there are directives for linear gradients, but I do not know
>> how to build the function to use svg directives and such that the target
>> greyscale value is reached at the x-position of a given notehead.
>>
>> Also, ideally I would be able to use spacer rests to give intermediary
>> values along the way, since the curve is actually not linear.
>>
>> Thanks in advance and my apologies if I have been unclear.
>>
>> Best,
>> Michael
Hi Michael,
not sure I've got you right.
Probably the quick hack below may give you a starting point.
It will not work with spacers though, because they don't cause a NoteColumn.
Cheers,
Harm
#(define (make-filled-box-stencil-list x-coords half-thick colors rl)
(if (null? (cdr x-coords))
rl
(make-filled-box-stencil-list
(cdr x-coords)
half-thick
(cdr colors)
(cons
(stencil-with-color
(make-filled-box-stencil
(cons (car x-coords) (cadr x-coords))
(cons (- half-thick) half-thick))
(car colors))
rl))))
\version "2.19.65"
foo =
\override TextSpanner.stencil =
#(lambda (grob)
(let* ((ncs (ly:grob-object grob 'note-columns))
(nc-ls
(if (ly:grob-array? ncs)
(ly:grob-array->list ncs)
'()))
(sys (ly:grob-system grob))
(nc-exts
(map
(lambda (nc)
(ly:grob-extent nc sys X))
nc-ls))
(left-info
(ly:grob-property grob 'left-bound-info))
(right-info
(ly:grob-property grob 'right-bound-info))
(thick (ly:grob-property grob 'thickness 1))
(x-coords
(map
(lambda (e)
(- e (assoc-get 'X left-info)))
`(
,(assoc-get 'X left-info)
,@(map
interval-center
(drop-right (drop nc-exts 1) 1))
,(assoc-get 'X right-info))))
(ls (iota (1- (length x-coords)) 20 20))
(color-gradient
(assoc-get 'color-gradient (ly:grob-property grob 'details) '(1)))
;; overkill below ...
(safe-color-gradient-ls
(append
color-gradient
(make-list (length x-coords) (last color-gradient))))
(color
(assoc-get 'color (ly:grob-property grob 'details)))
(colors
(map
(lambda (n)
(x11-color (string->symbol (format #f "~a~a" (or color
'grey) n))))
safe-color-gradient-ls)))
(apply
ly:stencil-add
(make-filled-box-stencil-list x-coords thick colors '()))))
{
\override TextSpanner.thickness = 0.5
%% make sure color and it's gradient exists, otherwise all's black
\override TextSpanner.details.color = #'grey
\override TextSpanner.details.color-gradient = #'(60 40 20)
\foo
c''2\startTextSpan
d''
e''
f''\stopTextSpan
}
{
\override TextSpanner.thickness = 0.5
\override TextSpanner.details.color = #'LightCyan
\override TextSpanner.details.color-gradient = #'(2 3 4)
\foo
c''2\startTextSpan
d''
e''
f''\stopTextSpan
}
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