%% Generated by lilypond-book.py
%% Options: [indent=0\mm,verbatim,doctitle,alt=[image of music],texidoc,line-width=160\mm]
\include "lilypond-book-preamble.ly"


% ****************************************************************
% Start cut-&-pastable-section
% ****************************************************************



\paper {
  #(define dump-extents #t)
  
  indent = 0\mm
  line-width = 160\mm
  force-assignment = #""
  line-width = #(- line-width (* mm  3.000000))
}

\layout {
  
}



% ****************************************************************
% ly snippet:
% ****************************************************************
\sourcefilename "three-sided-box.ly"
\sourcefileline 0
%% Do not edit this file; it is auto-generated from LSR http://lsr.dsi.unimi.it
%% This file is in the public domain.
\version "2.12.0"

\header {
  lsrtags = "rhythms, text"

  texidoc = "
This example shows how to add a markup command to get a three sided box
around some text (or other markup).

"
  doctitle = "Three-sided box"
} % begin verbatim

% New command to add a three sided box, with sides north, west and south
% Based on the box-stencil command defined in scm/stencil.scm
% Note that ";" is used to comment a line in Scheme
#(define-public (NWS-box-stencil stencil thickness padding)
  "Add a box around STENCIL, producing a new stencil."
  (let* ((x-ext (interval-widen (ly:stencil-extent stencil 0) padding))
         (y-ext (interval-widen (ly:stencil-extent stencil 1) padding))
         (y-rule (make-filled-box-stencil (cons 0 thickness) y-ext))
         (x-rule (make-filled-box-stencil
                  (interval-widen x-ext thickness) (cons 0 thickness))))
;    (set! stencil (ly:stencil-combine-at-edge stencil X 1 y-rule padding))
    (set! stencil (ly:stencil-combine-at-edge stencil X -1 y-rule padding))
    (set! stencil (ly:stencil-combine-at-edge stencil Y 1 x-rule 0.0))
    (set! stencil (ly:stencil-combine-at-edge stencil Y -1 x-rule 0.0))
    stencil))

% The corresponding markup command, based on the \box command defined 
% in scm/define-markup-commands.scm
#(define-markup-command (NWS-box layout props arg) (markup?)
  "Draw a box round @var{arg}.  Looks at @code{thickness},
@code{box-padding} and @code{font-size} properties to determine line
thickness and padding around the markup."  
  (let* ((th (chain-assoc-get 'thickness props  0.1))
         (size (chain-assoc-get 'font-size props 0))
         (pad (* (magstep size)
                 (chain-assoc-get 'box-padding props 0.2)))
         (m (interpret-markup layout props arg)))
    (NWS-box-stencil m th pad)))

% Test it:

\layout { ragged-right = ##f }
\relative c' {
  c2^\markup { \NWS-box ABCD }
  c2^\markup { \NWS-box \note #"4" #1.0 }
}



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% end ly snippet
% ****************************************************************