Re: box around notes

[David Nalesnik]

Hi Klaus,

On Sat, Jan 10, 2015 at 7:03 PM, Klaus Blum <address@hidden> wrote:

Hi David,

thanks for your work - this is a really great tool.

I often work with things like this:
http://lsr.di.unimi.it/LSR/Item?id=960
<http://lsr.di.unimi.it/LSR/Item?id=960>
so what I found in this thread is very interesting for analysis purposes.

I started to try some modifications on color, thickness, solid background
etc:
<http://lilypond.1069038.n5.nabble.com/file/n170307/boxer-attempt.png>

Now THAT looks cool!

 

Unfortunately, I'm helpless with scheme, so I don't know how to get this to
an end...
I added two properties to the grob definition (and also made some additions
to the drawing procedures):

*
#(add-grob-definition
  'Box
  `(
     (stencil . ,box-stil)
     (thickness . 0.1)  ; added by KB
     (filled . #f)      ; added by KB
     (meta . ((class . Item)
              (interfaces . ())))))
*

Now I tried to modify these properties:

*
\override Score.Box.thickness = 0.5
\override Score.Box.filled = ##t
*

Changing the "thickness" property works well, but changing "filled"
obviously has no effect. Instead, I get this error:
/Warnung: Eigenschafts-Typprüfung für »filled« (backend-type?) kann nicht
gefunden werden.  vielleicht ein Tippfehler?
Warnung: Zuweisung wird übersprungen/
can't find property type-check for »filled« (backend-type?). perhaps a
typing error?
Warning: skipping assignment

You need to make LilyPond aware of the new property: what type does it have? does it have a documentation string?  (The latter is important because the documentation in the Internals Reference is generated automatically.)

Add the following lines above the stencil function (make-box):

%%%%%%%%%%%

#(define (define-grob-property symbol type? description)

  (if (not (equal? (object-property symbol 'backend-doc) #f))

      (ly:error (_ "symbol ~S redefined") symbol))

  (set-object-property! symbol 'backend-type? type?)

  (set-object-property! symbol 'backend-doc description)

  symbol)

#(map

  (lambda (x)

    (apply define-grob-property x))

  `(

    (filled ,boolean?

      "Should we fill in this box?")

; add more properties here

  ))

%%%%%%%%%%%%%

Now here is where you might run into a problem with the new grob.  Let's say you decide to run a batch of files using this new grob:

>lilypond file1.ly file2.ly [...]

You'll get an error about "property redefined," but it will work.  (I suppose you could remove the error warning in the definition above if the errors in the log bother you.)

Hope this is helpful,

David