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 x@tie{}radius @var{x-radius},
y@tie{}radius @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 <
pierre.schneider.pa...@gmail.com> 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 x@tie{}radius @var{x-radius},
> y@tie{}radius @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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