Colored arrows (alternative method)

[Big Noise]

Hi everyone,

in this thread I'll continue a "side product" from another thread:
http://lilypond.1069038.n5.nabble.com/scheme-problem-colored-background-layers-tc169023.html

The idea was to create colored arrows that automatically adapt to layout 
changes.
Thanks to Urs and Malte for your ideas on that.

Here is my first attempt:

% --------------------------------------------------------------------------
\version "2.18.2"

forwardArrow = #(define-music-function (parser location color)
                  (color?)
                  #{ % Cross-staff arrows are made using the VoiceFollower:
                    \once \override VoiceFollower.layer = #-5
                    % To have the arrow behind the staff, choose a value below 
0 for the layer.
                    % If you want the arrows to cover the notes, choose a value 
of 2 or more.
                    \once \override VoiceFollower.thickness = #'5    % line 
thickness
                    \once \override VoiceFollower.color = #color
                    \once \override VoiceFollower.bound-details.left.padding = 
#4
                    \once \override VoiceFollower.bound-details.right.padding = 
#5
                    % Padding can be adjusted to move arrow ends closer to the 
notes
                    \once \override VoiceFollower.bound-details.right.arrow = 
##t
                    \once \override VoiceFollower.breakable = ##t  % ##f 
prevents line breaks within an arrow
                    % Arrows within the same staff use the Glissando spanner:
                    \once \override Glissando.layer = #-5
                    \once \override Glissando.thickness = #'5
                    \once \override Glissando.color = #color
                    \once \override Glissando.bound-details.left.padding = #4
                    \once \override Glissando.bound-details.right.padding = #5
                    \once \override Glissando.bound-details.right.arrow = ##t
                    \once \override Glissando.breakable = ##t
                  #})

backwardArrow = #(define-music-function (parser location color)
                  (color?)
                  #{
                    \once \override VoiceFollower.layer = #-5
                    \once \override VoiceFollower.thickness = #'5    % line 
thickness
                    \once \override VoiceFollower.color = #color
                    \once \override VoiceFollower.bound-details.left.padding = 
#4
                    \once \override VoiceFollower.bound-details.right.padding = 
#5
                    % pretty much the same stuff, but arrow head at the left 
side:
                    \once \override VoiceFollower.bound-details.left.arrow = ##t
                    \once \override VoiceFollower.breakable = ##t
                    \once \override Glissando.layer = #-5
                    \once \override Glissando.thickness = #'5
                    \once \override Glissando.color = #color
                    \once \override Glissando.bound-details.left.padding = #4
                    \once \override Glissando.bound-details.right.padding = #5
                    \once \override Glissando.bound-details.left.arrow = ##t % 
same here...
                    \once \override Glissando.breakable = ##t
                  #})


\relative c' {
  <<
    % Usage: place the arrow function call before the note, the glissando 
statement after the note
    \new Staff = upper {c4 d e \backwardArrow #blue c \glissando    R1   R1   
R1   R1   R1   c4 d e c   e1 d c}
    \new Staff = middle {R1    c4 d e c   e8 d e f g f e c    d c d e f e f d   
 c1    R1    R1*4}
    \new Staff = lower
    {<<
      {R1   R1    c4 d e \forwardArrow #blue c\glissando    R1   c4 d e c    d 
c b2    R1*4}
      { % Cross-staff arrows use an additional voice with hidden notes between 
them.
        % To make these notes visible, uncomment the following line:
        %      \override NoteHead.color = #cyan \override NoteHead.layer = #2
        % and remove the following "\hideNotes" line:
        \hideNotes
        \set Voice.followVoice = ##t
        \change Staff = "upper"  c4 s2.
        % place the arrow function call immediately before the staff change:
        \backwardArrow #green
        \change Staff = "middle"  g4 s2.
        \forwardArrow #red
        \change Staff = "lower"  c4  s2.    s1    c4 s2.
        \break
        \forwardArrow #red
        \change Staff = "middle"  c4 s2.
        \forwardArrow #red
        \change Staff = "upper"  c4 s2.
      }
    >>}
  >>
}

% --------------------------------------------------------------------------

Any suggestions for improvement? (I'll wait for you before turning this 
one into a snippet...)

Cheers,
Klaus



Am 04.12.2014 um 18:01 schrieb address@hidden:

From: Malte Meyn To: address@hidden Subject: Re: scheme problem: 
colored background, layers Am 04.12.2014 um 00:13 schrieb Urs Liska:

> Am I seeing correctly that the arrows are coded with absolute
> coordinates from their starting points (i.e. they wouldn't adapt to
> layout changes)?
> This is not at all diminishing your snippet, but it would be absolutely
> awesome if someone could extend this to override the stencil of, say, a
> slur, so the arrows would "snap" to two notes.
Probably a glissando or a voice follower (both engraved by the
Note_head_line_engraver) would be better/easier to reuse than a slur
since these arrws look like some sort of ?voice following? ;)