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Re: Oval stencil and oval markup suggestions


From: Pierre Perol-Schneider
Subject: Re: Oval stencil and oval markup suggestions
Date: Thu, 4 Apr 2019 20:38:30 +0200

Or even an oval stencil with 4 control points:

%%
#(define-public (make-oval-stencil-var x-radius y-radius thickness fill)
  "Make an oval from two Bezier curves, of address@hidden @var{x-radius},
  address@hidden @code{y-radius}, and thickness @var{thickness} with fill
  defined by @code{fill}."
    (let*
        ((x-out-radius (+ x-radius (/ thickness 2.0)))
         (y-out-radius (+ y-radius (/ thickness 2.0)))
         (x-max x-radius)
         (x-min (- x-radius))
         (y-max y-radius)
         (y-min (- y-radius))
         (commands `(,(list 'moveto x-max 0)
                     ,(list 'curveto x-max (/ y-max 1.8) (/ x-max 1.8)
y-max 0 y-max)
                     ,(list 'curveto (/ x-min 1.8) y-max x-min (/ y-max
1.8) x-min 0)
                     ,(list 'curveto x-min (/ y-min 1.8) (/ x-min 1.8)
y-min 0 y-min)
                     ,(list 'curveto (/ x-max 1.8) y-min x-max (/ y-min
1.8) x-max 0)
                     ,(list 'closepath)))
         (command-list (fold-right append '() commands)))
      (ly:make-stencil
       `(path ,thickness `(,@',command-list) 'round 'round ,fill)
       (cons (- x-out-radius) x-out-radius)
       (cons (- y-out-radius) y-out-radius))))
%%

Cheers,
Pierre

Le jeu. 4 avr. 2019 à 17:33, Pierre Perol-Schneider <
address@hidden> a écrit :

> Hi Dev Team,
> Here's some thougts:
>
> %%%%%%
> \version "2.19.83"
>
> %% The oval stencil commands uses beziers curves that cause some side
> effects:
> \markuplist {
>   \line\vcenter {
>     "Circle, radius = 2 : "
>     \stencil #(make-circle-stencil 2 .13 #f)
>   }
>   \line\vcenter {
>     "Oval, x-radius = y-radius = 2 : "
>     \stencil #(make-oval-stencil 2 2 .13 #f)
>   }
>   \line\vcenter {
>     "Oval extents, x-radius = y-radius = 2 : "
>     \box\stencil #(make-oval-stencil 2 2 .13 #f)
>   }
> }
>
> %% Here's a suggestion with a corrected y-radius in order to reach a quasi
> circle:
> #(define-public (make-oval-stencil-var x-radius y-radius thickness fill)
>   "Make an oval from two Bezier curves, of address@hidden @var{x-radius},
>   address@hidden @code{y-radius}, and thickness @var{thickness} with fill
>   defined by @code{fill}."
>     (let*
>         ((x-out-radius (+ x-radius (/ thickness 2.0)))
>          (y-out-radius (+ y-radius (/ thickness 2.0)))
>          (x-max x-radius)
>          (x-min (- x-radius))
>          (y-max (* y-radius (+ 1 (/ 1 3)))) ; <= max deviation < 1%
>          (y-min (* (- y-radius) (+ 1 (/ 1 3)))) ; <= max deviation < 1%
>          (commands `(,(list 'moveto x-max 0)
>                      ,(list 'curveto x-max y-max x-min y-max x-min 0)
>                      ,(list 'curveto x-min y-min x-max y-min x-max 0)
>                      ,(list 'closepath)
>                      ))
>          (command-list (fold-right append '() commands)))
>       (ly:make-stencil
>        `(path ,thickness `(,@',command-list) 'round 'round ,fill)
>        (cons (- x-out-radius) x-out-radius)
>        (cons (- y-out-radius) y-out-radius))))
>
>
> \markuplist {
>   % Test #1:
>   \line\vcenter {
>     "make-oval-stencil-var: "
>     \box\stencil #(make-oval-stencil-var 2 2 .13 #f)
>     " v.s. make-circle-stencil: "
>     \box\stencil #(make-circle-stencil 2 .13 #f)
>   }
>   % Test #2:
>   \vspace #1 "make-oval-stencil-var & make-circle-stencil combined:"
> \vspace #.3
>   \translate #'(8 . 0)
>   \line {
>     \scale #'(5 . 5) {
>       \combine
>       \with-color #blue
>       \draw-circle #2 #.13 ##f
>       \with-color #red
>       \stencil #(make-oval-stencil-var 2 2 .13 #f)
>     }
>     \scale #'(5 . 5) {
>       \combine
>       \with-color #red
>       \stencil #(make-oval-stencil-var 2 2 .13 #f)
>       \with-color #blue
>       \draw-circle #2 #.13 ##f
>     }
>   }
>   \vspace #1
> }
>
> %% Here comes a suggestion for the markup command:
> #(define-public (oval-stencil-var stencil thickness x-padding y-padding)
>   "Add an oval around @code{stencil}, padded by the padding pair,
> producing a var stencil."
>   (let* ((x-ext (ly:stencil-extent stencil X))
>          (y-ext (ly:stencil-extent stencil Y))
>          (x-length (+ (interval-length x-ext) x-padding thickness))
>          (y-length (+ (interval-length y-ext) y-padding thickness))
>          (x-radius (* 0.707 x-length) )
>          (y-radius (* 0.707 y-length) )
>          (oval (make-oval-stencil-var x-radius y-radius thickness #f)))
>
>     (ly:stencil-add
>      stencil
>      (ly:stencil-translate oval
>                            (cons
>                             (interval-center x-ext)
>                             (interval-center y-ext))))))
>
> #(define-markup-command (oval-var layout props arg)
>   (markup?)
>   #:category graphic
>   #:properties ((thickness 1)
>                 (font-size 0)
>                 (x-padding .1) ; <= possible corrected padding
>                 (y-padding .1)) ; <= possible corrected padding
>   "
> @cindex drawing oval around text
>
> Draw an oval around @var{arg}.  Use @code{thickness},
> @code{x-padding}, @code{x-padding} and @code{font-size} properties to
> determine
> line thickness and padding around the markup.
>
> @lilypond[verbatim,quote]
> \\markup {
>   \\oval-var {
>     Hi
>   }
> }
> @end lilypond"
>   (let ((th (* (ly:output-def-lookup layout 'line-thickness)
>                thickness))
>         (pad-x (* (magstep font-size) x-padding))
>         (pad-y (* (magstep font-size) y-padding))
>         (m (interpret-markup layout props arg)))
>     (oval-stencil-var m th pad-x pad-y)))
>
>
> %% Comparative test:
> \markup {
>   "oval: "
>   \box\oval "Hi"
>   " v.s. oval-var markups: "
>   \box\oval-var "Hi"
> }
>
> %%%%%
>
> Cheers,
> Pierre
>


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