Re: Display the control points of a slur

[Urs Liska]

Am 15.11.19 um 00:06 schrieb Aaron Hill:
> On 2019-11-14 2:20 pm, Paolo Prete wrote:
> > I propose to include your snippet in a new release of Lilypond because
> > it's very useful.
>
> It would be nice to include more debug annotations within LilyPond.  
> If I am not mistaken, we currently have the following options:
>
>   \paper { annotate-spacing = ##t }
>   #(ly:set-option 'debug-skylines)
>   \override [Non]PaperColumn.stencil = #ly:paper-column::print
>
> For the future, we could add support for these cases:
>
> - Plotting curve control points.
> - Visualizing the extents and origins of grob stencils.
> - Indicating the relationships between grobs (i.e. parents, children, 
> siblings).
>
> Are there other annotations that folks would find helpful? Providing 
> there is enough interest in such support, we should open a ticket for 
> tracking the work.


Frescobaldi also offers the following options (in the Layout Control Tool):

- coloring voices with explicit \voiceXXX
  (unfortunately implicit ones in polyphonic settings are not possible)
- coloring explicit directions with ^ or _
- print the grob names

What I'd find interesting in addition would be:

- visualizing extra-offset (by plotting a line between the final and the 
original refpoints)
- visualizing *other* properties of bezier curves, for example angles 
and ratios
  (those that can be set with \shapeII). These are of course not 
available as properties
  but would have to be calculated.
  The results should be printed in a semi-transparent (?) rectangle 
overlaying the score
- in a similar vein there could be a more generic function to "debug" a 
grob by printing
  selected property values on top of the score (something like a ballon 
text, but overlaid)

These visualizations should also be possible to switch on and off in the 
course of the document to just apply them to a selected range or even a 
single item.

Urs


> -- Aaron Hill