Re: Stencil questions (adding text and defining line style)

[Nathan Ho]

On 2016-09-21 11:49, Urs Liska wrote:
> Concretely I want to add a text element at a certain position to a
>   (ly:stencil-add
> construction.

Hi Urs,

grob-interpret-markup is the way to create text. You can position it 
with ly:stencil-translate, and add it to another stencil using 
ly:stencil-add:

(ly:stencil-add
  your-current-stencil
  (ly:stencil-translate
    (grob-interpret-markup
      grob
      (markup "Hey"))
    '(2 . 3)))

ly:stencil-combine-at-edge is also really handy if you want to position 
a stencil relative to bounding box of another one, like "place this 
thing vertically centered so its left edge is 0.1 staff spaces away from 
the right edge of this other thing."

> The other thing I didn't find is: how can I create a dashed (or
> otherwise styled) line stencil with make-line-stencil?

I don't think it's possible, but you can use draw-dashed-line / 
draw-dotted-line in a grob-interpret-markup.

> More generally: how can I learn more about these things? Searching
> lilypond.org seems to only point to snippets and no real explanations.

I've generally relied on examining examples in the LSR to learn about 
this sort of thing. The "Scheme functions" section of the Notation and 
Internals manuals is helpful, but a lot of the functions are not clearly 
documented, and they're definitely not presented in a manner that's 
conducive to step-by-step learning.

Since it's pretty tough to use stencils, as you can see I resort a lot 
to markups. They're not the perfect solution, but they're better 
documented and easier to use.


Nathan