+ (let* ((details (ly:grob-property grob 'bound-details))
+ (left-details (ly:assoc-get 'left details))
+ (my-padding (ly:assoc-get 'padding left-details))
+ (script-padding (ly:grob-property left-bound 'right-padding 0)))
+
+ (and (number? my-padding)
+ (ly:grob-set-nested-property! grob
+ '(bound-details left attach-dir)
+ RIGHT)
+ (ly:grob-set-nested-property! grob
+ '(bound-details left padding)
+ (+ my-padding script-padding)))))))
+
+(define-public (make-connected-line points grob)
+ "Takes a list of points, @var{points}.
+Returns a line connecting @var{points}, using @code{ly:line-interface::line},
+gets layout information from @var{grob}"
+ (define (connected-points grob ls pts)
+ (if (not (pair? (cdr pts)))
+ (reduce ly:stencil-add empty-stencil ls)
+ (connected-points
+ grob
+ (cons
+ (ly:line-interface::line
+ grob
+ (car (first pts))
+ (cdr (first pts))
+ (car (second pts))
+ (cdr (second pts)))
+ ls)
+ (cdr pts))))
+ (if (< (length points) 2)
+ (begin
+ (ly:warning
+ "´make-connected-line´ needs at least two points: ~a"
+ points)
+ empty-stencil)
+ (connected-points grob '() points)))
+
+(define ((elbowed-hairpin coords mirrored?) grob)
+ "Create hairpin based on a list of @var{coords} in @code{(cons x y)}
+form. @code{x} is the portion of the width consumed for a given line
+and @code{y} is the portion of the height. For example,
+@code{'((0 . 0) (0.3 . 0.7) (0.8 . 0.9) (1.0 . 1.0))} means that at the point
+where the hairpin has consumed 30% of its width, it must
+be at 70% of its height. Once it is to 80% width, it
+must be at 90% height. It finishes at 100% width and 100% height.
+If @var{coords} does not begin with @code{'(0 . 0)} the final hairpin may have
+an open tip. For example '(0 . 0.5) will cause an open end of 50% of the usual
+height.
+@var{mirrored?} indicates if the hairpin is mirrored over the Y-axis or if
+just the upper part is drawn.
+Returns a function that accepts a hairpin grob as an argument
+and draws the stencil based on its coordinates.
+
+@lilypond[verbatim,quote]
+#(define simple-hairpin
+ (elbowed-hairpin '((0 . 0)(1.0 . 1.0)) #t))
+
+\\relative c' {
+ \\override Hairpin #'stencil = #simple-hairpin
+ a\\p\\< a a a\\f
+}
+@end lilypond
+"
+ (define (scale-coords coords-list x y)
+ (map
+ (lambda (coord) (cons (* x (car coord)) (* y (cdr coord))))
+ coords-list))
+
+ (define (hairpin::print-part points decresc? me)
+ (let ((stil (make-connected-line points me)))
+ (if decresc? (ly:stencil-scale stil -1 1) stil)))
+
+ ;; outer let to trigger suicide
+ (let ((sten (ly:hairpin::print grob)))
+ (if (grob::is-live? grob)
+ (let* ((decresc? (eqv? (ly:grob-property grob 'grow-direction) LEFT))
+ (xex (ly:stencil-extent sten X))
+ (lenx (interval-length xex))
+ (yex (ly:stencil-extent sten Y))
+ (leny (interval-length yex))
+ (xtrans (+ (car xex) (if decresc? lenx 0)))
+ (ytrans (car yex))
+ (uplist (scale-coords coords lenx (/ leny 2)))
+ (downlist (scale-coords coords lenx (/ leny -2)))
+ (stil
+ (ly:stencil-aligned-to
+ (ly:stencil-translate
+ (ly:stencil-add
+ (hairpin::print-part uplist decresc? grob)
+ (if mirrored?
+ (hairpin::print-part downlist decresc? grob)
+ empty-stencil))
+ (cons xtrans ytrans))
+ Y CENTER))
+ (stil-y-extent (ly:stencil-extent stil Y)))
+ ;; Return a final stencil properly aligned in Y-axis direction and with
+ ;; proper extents. Otherwise stencil-operations like 'box-stencil' will
+ ;; return badly. Extent in X-axis direction is taken from the original,
+ ;; in Y-axis direction from the new stencil.
+ (ly:make-stencil (ly:stencil-expr stil) xex stil-y-extent))
+ ;; return empty, if no Hairpin.stencil present.
+ '())))
+(export elbowed-hairpin)
+
+(define-public flared-hairpin
+ (elbowed-hairpin '((0 . 0) (0.95 . 0.4) (1.0 . 1.0)) #t))
+
+(define-public constante-hairpin
+ (elbowed-hairpin '((0 . 0) (1.0 . 0.0) (1.0 . 1.0)) #f))