Hi list,
several months ago David Nalesnik (together with input from others)
updated the older \shape function that allows shaping the control-points
of curve grobs - which provided a massive increase in productivity when
dealing with slurs etc.
For example, one major improvement was the handling of broken curves.
After it was finished the function has been incorporated in LilyPond's code
(http://code.google.com/p/lilypond/issues/detail?id=2572)
and was recently changed further
(http://code.google.com/p/lilypond/issues/detail?id=2873)
However, David removed one very interesting feature from the function in
order to be able to provide a more concise and clean patch. In 'our'
version of the function the function issued warnings (and optionally
colored the curves) when it found a mismatch between the number of curve
siblings (broken parts of the curve) and lists of offset-pairs.
This is a very useful feature because you get noticed if changed line
breaking results in a different number of curve parts (which is most
likely to spoil your tweaking).
See the attachment for the older version of the function. Please note
that it just redefines the built-in \shape function and doesn't use it.
It isn't meant as the model for a new implementation (as I know the
function has in the meantime been changed already) but to show the
mentioned functionality.
What I would like to achieve with this email is that someone opens a new
issue with the request for inclusion of this functionality to the \shape
function now included in Lilypond.
David suggested he might revisit his code to make it more stable.
What i consider essential is the part that issues warnings on the
console output.
Personally I like the coloring very much, but I could imagine that some
people would find this too intrusive (even if the default color would be
black?)
Best
Urs
%{
Exports the function
- shape
that manipulates curves through defining
offsets to LilyPond's default decisions (instead of having to find
hard-coded coordinates. This has the main advantage that there is
a good chance that the override also works when the layout changes.
There are several additions to an earlier version available at
the LilyPond Snippet Repository:
- The function now handles slurs that are broken into more than one snippet ('siblings')
- Any sibling can be shaped individually or left alone (i.e. it uses LilyPond's default)
- If the number of siblings doesn't match the number of arguments
(due to wrong input or changed layout)
the function issues an informative warning including the reference to the input source
and colors the respective curve so it can be easily found in the score
- the used color can be personalized through a variable that can either be set
in the library file or at any given moment in the music input
(leaving it set to default black makes it seem there is no coloring)
Usage:
Call \shape grob-name immediately before the curve you want to modify.
A set of control-point offsets is given as a list of four pairs,
each specifying x and y offsets ((x1 . y1) (x2 . y2) (x3 . y3) (x4 . y4))
for example
\shape Slur #'( ( ( 0 . 0 ) ( 5 . 7 ) ( 0 . -15 ) (0 . -4) ) ) )
keep in mind: You need one pair of brackets around the whole function,
one pair of brackets around the set of control-points and
one pair around each control-point
You have to take care to give exactly four points.
If you give less or more pairs you won't see warnings or errors but the curves will be very strange.
Giving no point at all is equivalent to ( (0 . 0) (0 . 0) (0 . 0) (0 . 0) )
For more than one curve sibling enter the appropriate number of sets of control-points
for example
\shapeSlur #'( ( ( 0 . 0 ) ( 5 . 7 ) ( 0 . -15 ) (0 . -4) )
( ( 3 . 0 ) ( 3 . 2 ) ( 12 . 15 ) (0 . -4) )
()
)
(In this example the third sibling is left with ts default control-points)
If the number of control-points sets doesn't match the actual
number of siblings the curve is broken into the function does two things:
- issue an informative warning about the number of expected and existent siblings
as well as pointing to the line of the music input
- color the offending curve in the score so it can easily be spotted
This is especially useful when the mismatch isn't the result of wrong input but
of a change in layout
You can personalize the color with the variable curve-warning-color.
Here are a few possibilities to set this variable:
#(define curve-warning-color (rgb-color 0 0 1))
#(define curve-warning-color (x11-color 'green))
#(define curve-warning-color magenta)
The default is black.
You can either change the color within this file or
anywhere in your source files (which allows to change the color during a piece
(whatever this may be useful for ...))
For usage examples see the lower part of this file.
%}
#(define curve-warning-color magenta)
#(define ((offset-control-points offsets function) grob)
(let ((coords (function grob)))
(if (null? offsets)
coords
(map
(lambda (x y)
(coord-translate x y))
coords offsets))))
#(define ((shape-curve offsets location) grob)
(let* ((orig (ly:grob-original grob))
(siblings (if (and (ly:grob? orig) (ly:spanner? grob))
(ly:spanner-broken-into orig) '() ))
(total-found (length siblings))
(function (assoc-get 'control-points
(reverse (ly:grob-basic-properties grob))))
(grob-name
(assoc-get 'name
(assoc-get 'meta
(ly:grob-basic-properties grob)))))
(define (helper sibs offs)
(if (and (eq? (car sibs) grob)
(pair? offs))
((offset-control-points (car offs) function) grob)
(if (pair? offs)
(helper (cdr sibs) (cdr offs))
((offset-control-points '() function) grob))))
; standardize input so #'((dx1 . dy1) . . . )
; and #'( ((dx1 . dy1) . . . ) ) possible
(if (not (list? (car offsets)))
(set! offsets (list offsets)))
; warnings
(if (not (= (length offsets) total-found))
(if (zero? total-found)
(if (pair? (cdr offsets))
(begin
(set! (ly:grob-property grob 'color) curve-warning-color)
(ly:input-warning location
"~a is unbroken, modifications for ~a pieces requested"
grob-name (length offsets))))
(if (eq? (last siblings) grob) ; print warning only once
(begin
(for-each
(lambda (piece) (set! (ly:grob-property piece 'color) curve-warning-color))
siblings)
(ly:input-warning location
"~a is broken into ~a pieces, modifications for ~a requested"
grob-name total-found (length offsets))))))
(if (>= total-found 2)
(helper siblings offsets)
((offset-control-points (car offsets) function) grob))))
shape =
#(define-music-function (parser location grob offsets)
(string? list?)
#{
\once \override $grob #'control-points =
#(shape-curve offsets location)
#})
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Usage:
%% SLURS
\markup {
\underline "Default Slurs"
}
\relative c'' {
d4( d' b g g,8 f' e d c2)
\bar "||"
d4( d' b g
\break
g,8 f' e d c2)
}
\markup {
\underline "Modified"
}
\relative c'' {
%% UNBROKEN
%% remove semicolon to see warning
\shape Slur #'(
((0 . -2.5) (-1 . 3.5) (0 . 0) (0 . -2.5))
;()
)
d4( d' b g g,8 f' e d c2)
\bar "||"
%% BROKEN
%% warning will show
\shape Slur #'(
((0 . -2.5) (0 . 1.5) (0 . 1) (0 . -1))
()
()
)
d4(^"(1st half only)" d' b g
\break
g,8 f' e d c2)
\bar "||"
%% both halves of the slur are modified
\shape Slur #'(
((0 . -2.5) (0 . 1.5) (0 . 1) (0 . -1))
((1 . 2) (0 . 1) (0 . 1) (0 . 0))
)
d4(^"(both halves)" d' b g
\break
g,8 f' e d c2)
}
%% TIES
\relative c'' {
cis1~
cis
\shape Tie #'((0 . 0) (0 . 1) (0 . 1) (0 . 0))
cis~
cis
\shape Tie #'((0 . 0) (0 . 1) (0 . 1) (0 . 0))
cis~
\break
cis
\break
\shape Tie #'(
()
((-0.25 . 0) (0 . -0.25) (0 . -0.25) (0 . -1))
)
cis~
\break
cis
}
\paper {
indent = 0
ragged-right = ##t
}
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