Re: Whiteout box function by Thomas Morley / need help

[Karol Majewski]

Thanks again Harm. This is very useful function. Hopefully I'm not the only one 
who appreciates it.


> 
> Hi Karol,
> 
> below the revised function.
> 'moreWhiteout' takes one optional and two normal arguments:
> Specifying whether the stencil should be boxed (boolean), which grob
> (string) and the values to extent the stencil. These values can be
> given as simple pair, affecting only X-axis-extension or as list of
> pairs, affecting X- and Y-axis-extent.
> The boolean may be of some use for debugging, though it will affect
> spacing! Perhaps I should delete it ...
> 
> Otherwise I did some clean up and made the function more robust.
> Please test.
> 
> \version "2.19.3"
> 
> moreWhiteout =
> #(define-music-function (parser location better-viewing? grob-name adds)
>   ((boolean? #f) string? pair?)
> 
>   (define (interval-add iv-1 iv-2)
>     (cons (+ (car iv-1)(car iv-2))
>           (+ (cdr iv-1)(cdr iv-2))))
> 
>   (define more-stencil-whiteout
>     (lambda (grob)
>       (let* ((function (assoc-get 'stencil
>                             (reverse (ly:grob-basic-properties grob))))
>              (stil ;; Ugh, is there no better way to test that a grob has no
>                    ;; 'stencil and that no other previous procedure assigned
>                    ;; a stencil-value to said grob?
>                    (if (and (procedure? function)
>                             (not (eq? (procedure-name function)
>                                       'more-stencil-whiteout)))
>                    (function grob)
>                    (begin
>                      (ly:warning "~a has no stencil. Ignoring" grob)
>                      #f))))
>         (if stil
>             (let*((x-ext (ly:stencil-extent stil X))
>                   (y-ext (ly:stencil-extent stil Y))
>                   (add-to-x-ext (if (pair? (car adds)) (car adds) adds))
>                   (add-to-y-ext (if (pair? (cdr adds)) (cadr adds) '(0 . 0)))
>                   (new-stil (ly:make-stencil
>                                (ly:stencil-expr stil)
>                                (interval-add x-ext add-to-x-ext)
>                                (interval-add y-ext add-to-y-ext))))
> 
> 
>                ;; please note: setting better-viewing #t, will add a little
>                ;; padding around the new stil and it will affect spacing in 
> most
>                ;; other cases, too.
>                ;; We let it in, perhaps it may be of some help in certain 
> cases.
>                (if better-viewing?
>                    (box-stencil new-stil 0.1 0.01)
>                    new-stil))
>             #f))))
> 
>   #{
>     %% Seems no longer needed:
>     %\once \override $grob-name . vertical-skylines = #'()
>     %% Better to add next two lines:
>     \once \override $grob-name . layer = #10
>     \once \override $grob-name . whiteout = ##t
>     \once \override $grob-name . stencil = #more-stencil-whiteout
>   #})
> 
> %%%%%%%%%%%%%%%%%%%%%%%
> %% EXAMPLE
> %%%%%%%%%%%%%%%%%%%%%%%
> 
> musicI = { \time 2/4 \repeat unfold 16 b8 }
> 
> musicII = {
>   r2
>   %% apply to X- and Y-axis
>   \moreWhiteout TextScript #'((-2 . 0.5)(0 . 2))
>   b4^"XXXXXX" b
>   r2
>   %% apply to X-axis only
>   \moreWhiteout ##t TextScript #'(-2 . 0.5)
>   b4^"XXXXXX" b
> }
> 
> 
> \new StaffGroup <<
>   \new Staff \relative c'' \musicI
>   \new Staff \relative c'' \musicII
> >>
> 
> Ofcourse the extension happens as a rectangle.
> No idea to do it different.
> 
> > BTW, In documentation for 2.19 it's written that default value for 
> DynamicText.extra-spacing-width is '(+inf.0 . -inf.0), which is not true 
> anymore.
> 
> I think you're wrong.
> The following returns '(+inf.0 . -inf.0) !
> 
> {
>   \override DynamicText.after-line-breaking =
>     #(lambda (grob) (write (ly:grob-property grob 'extra-spacing-width)))
>   c1\f
> }
> 
> HTH,
>   Harm