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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