1 ;;; page-layout.scm -- page breaking and page layout
3 ;;;; source file of the GNU LilyPond music typesetter
5 ;;;; (c) 2004 Jan Nieuwenhuizen <janneke@gnu.org>
6 ;;;; Han-Wen Nienhuys <hanwen@cs.uu.nl>
8 (use-modules (oop goops describe)
12 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
14 (define-class <optimally-broken-page-node> ()
15 (prev #:init-value '() #:accessor node-prev #:init-keyword #:prev)
16 (page #:init-value 0 #:accessor node-page-number #:init-keyword #:pageno)
17 (penalty #:init-value 0 #:accessor node-penalty #:init-keyword #:penalty)
18 (lines #:init-value 0 #:accessor node-lines #:init-keyword #:lines))
20 (define-method (display (node <optimally-broken-page-node>) port)
21 (map (lambda (x) (display x port))
23 "Page " (node-page-number node)
24 " Lines: " (node-lines node)
25 " Penalty " (node-penalty node)
28 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
31 (string-append "Engraved by LilyPond (version " (lilypond-version) ")"))
33 ;; TODO: take <optimally-broken-page-node> iso. page-number
34 ;; for all of these functions ?
36 (define-public (plain-header paper scopes page-number last?)
37 "Standard header for a part: page number --outside-- and instrument--centered."
39 (let* ((props (page-properties paper) )
40 (pnum (markup #:bold (number->string page-number)))
41 (instr (ly:modules-lookup scopes 'instrument))
42 (line (list "" (if (markup? instr) instr "") pnum)))
44 (if (even? page-number)
45 (set! line (reverse line)))
49 paper props (make-fill-line-markup line))
54 ;; TODO: add publisher ID on non-first page.
55 (define-public (plain-footer paper scopes page-number last?)
56 "Standard footer. Empty, save for first (copyright) and last (tagline) page."
59 ((props (page-properties paper))
60 (copyright (ly:modules-lookup scopes 'copyright))
61 (tagline-var (ly:modules-lookup scopes 'tagline))
62 (tagline (if (markup? tagline-var) tagline-var TAGLINE))
67 (ly:stencil-combine-at-edge
68 stencil Y DOWN (interpret-markup paper props tagline)
72 (if (and (= 1 page-number)
76 (ly:stencil-combine-at-edge
77 stencil Y DOWN (interpret-markup paper props copyright)
83 (define (page-headfoot paper scopes number sym sepsym dir last?)
84 "Create a stencil including separating space."
86 ((header-proc (ly:output-def-lookup paper sym))
87 (sep (ly:output-def-lookup paper sepsym))
88 (stencil (ly:make-stencil "" '(0 . 0) '(0 . 0)))
90 (if (procedure? header-proc)
91 (header-proc paper scopes number last?)
94 (if (and (number? sep) (ly:stencil? head-stencil))
96 (ly:stencil-combine-at-edge
97 stencil Y dir head-stencil
102 (define-public (default-page-music-height paper scopes number last?)
103 "Printable area for music and titles; matches default-page-make-stencil."
105 ((h (- (ly:output-def-lookup paper 'vsize)
106 (ly:output-def-lookup paper 'top-margin)
107 (ly:output-def-lookup paper 'bottom-margin)))
108 (head (page-headfoot paper scopes number 'make-header 'head-sep UP last?))
109 (foot (page-headfoot paper scopes number 'make-footer 'foot-sep DOWN last?)))
110 (- h (if (ly:stencil? head)
111 (interval-length (ly:stencil-extent head Y))
113 (if (ly:stencil? foot)
114 (interval-length (ly:stencil-extent foot Y))
119 (define-public (default-page-make-stencil lines paper scopes number last? )
120 "Construct a stencil representing the page from LINES. "
122 ((top-margin (ly:output-def-lookup paper 'top-margin))
124 ;; TODO: naming vsize/hsize not analogous to TeX.
126 (hsize (ly:output-def-lookup paper 'hsize))
127 (left-margin (/ (- hsize
128 (ly:output-def-lookup paper 'linewidth)) 2))
129 (vsize (ly:output-def-lookup paper 'vsize))
130 (bottom-edge (- vsize
131 (ly:output-def-lookup paper 'bottom-margin)))
133 (head (page-headfoot paper scopes number 'make-header 'head-sep UP last?))
134 (foot (page-headfoot paper scopes number 'make-footer 'foot-sep DOWN last?))
135 (line-stencils (map ly:paper-system-stencil lines))
136 (height-proc (ly:output-def-lookup paper 'page-music-height))
137 (music-height (height-proc paper scopes number last?))
138 (ragged (ly:output-def-lookup paper 'raggedbottom))
139 (ragged-last (ly:output-def-lookup paper 'raggedlastbottom))
140 (ragged-bottom (or (eq? #t ragged)
141 (and last? (eq? #t ragged-last))))
143 (spc-left (- music-height
144 (apply + (map (lambda (x)
145 (interval-length (ly:stencil-extent x Y)))
147 (stretchable-lines (remove ly:paper-system-title? (cdr lines)))
148 (stretch (if (or (null? stretchable-lines)
149 (> spc-left (/ music-height 2))
152 (/ spc-left (length stretchable-lines))))
154 (page-stencil (ly:make-stencil '()
155 (cons left-margin hsize)
156 (cons (- top-margin) 0)))
159 (set! page-stencil (ly:stencil-combine-at-edge
160 page-stencil Y DOWN head 0. 0.))
165 (ly:stencil-combine-at-edge
166 page-stencil Y DOWN (ly:paper-system-stencil l)
172 (set! was-title (ly:paper-system-title? l)))
175 (if (ly:stencil? foot)
179 (ly:stencil-translate
182 (+ (- bottom-edge) (- (car (ly:stencil-extent foot Y)))))
185 (ly:stencil-translate page-stencil (cons left-margin 0))
191 ;;; optimal page breaking
193 ;;; This is not optimal page breaking, this is optimal distribution of
194 ;;; lines over pages; line breaks are a given.
199 ; - separate function for word-wrap style breaking?
200 ; - raggedbottom? raggedlastbottom?
202 (define-public (ly:optimal-page-breaks
204 "Return pages as a list starting with 1st page. Each page is a list
207 (define (make-node prev lines page-num penalty)
208 (make <optimally-broken-page-node>
214 (define MAXPENALTY 1e9)
215 (define bookpaper (ly:paper-book-book-paper paper-book))
216 (define scopes (ly:paper-book-scopes paper-book))
217 (define (line-height line)
218 (ly:paper-system-extent line Y))
220 ;; FIXME: may need some tweaking: square, cubic
221 (define (height-penalty available used)
223 (let* ((left (- available used))
225 (relative (abs (/ left available))))
228 ;; too full, penalise more
229 (* 10 (1+ relative) relative)
231 ;; Convexity: two half-empty pages is better than 1 completely
233 (* (1+ relative) relative))))
235 (define (page-height page-number last?)
237 ((p (ly:output-def-lookup bookpaper 'page-music-height)))
240 (p bookpaper scopes page-number last?)
244 (define (cumulative-height lines)
245 (apply + (map line-height lines)))
247 (define (get-path node done)
248 "Follow NODE.PREV, and return as an ascending list of pages. DONE
249 is what have collected so far, and has ascending page numbers."
250 (if (is-a? node <optimally-broken-page-node>)
251 (get-path (node-prev node) (cons node done))
254 (define (combine-penalties user page prev)
257 (define (walk-paths done-lines best-paths current-lines last? current-best)
258 "Return the best optimal-page-break-node that contains
259 CURRENT-LINES. DONE-LINES.reversed ++ CURRENT-LINES is a consecutive
260 ascending range of lines, and BEST-PATHS contains the optimal breaks
261 corresponding to DONE-LINES.
263 CURRENT-BEST is the best result sofar, or #f."
265 (let* ((this-page-num (if (null? best-paths)
267 (1+ (node-page-number (car best-paths)))))
268 (prev-penalty (if (null? best-paths)
270 (node-penalty (car best-paths))))
271 (page-height (page-height this-page-num last?))
272 (space-used (cumulative-height current-lines))
273 (this-page-penalty (height-penalty page-height space-used))
274 (user-penalty (ly:paper-system-break-penalty (car current-lines)))
275 (total-penalty (combine-penalties
276 user-penalty this-page-penalty prev-penalty))
279 (< total-penalty (node-penalty current-best))))
280 (new-best (if better?
281 (make-node (if (null? best-paths)
285 this-page-num total-penalty)
291 "user pen " user-penalty " prev-penalty "
293 "better? " better? " total-penalty " total-penalty "\n"
294 "height " page-height " spc used: " space-used "\n"
295 "pen " this-page-penalty " lines: " current-lines "\n")))
297 (if (and (pair? done-lines)
298 ;; if this page is too full, adding another line won't help
299 (< this-page-penalty MAXPENALTY))
300 (walk-paths (cdr done-lines) (cdr best-paths)
301 (cons (car done-lines) current-lines)
305 (define (walk-lines done best-paths todo)
306 "Return the best page breaking as a single
307 <optimal-page-break-node> for optimally breaking TODO ++
308 DONE.reversed. BEST-PATHS is a list of break nodes corresponding to
312 (let* ((this-line (car todo))
313 (last? (null? (cdr todo)))
314 (next (walk-paths done best-paths (list this-line) last? #f)))
316 (walk-lines (cons this-line done)
317 (cons next best-paths)
320 (define (line-number node)
321 (ly:paper-system-number (car (node-lines node))))
323 (let* ((best-break-node (walk-lines '() '() lines))
324 (break-nodes (get-path best-break-node '()))
327 (if (ly:get-option 'verbose)
329 (format (current-error-port) "breaks: ~S\n" (map line-number break-nodes))
330 (force-output (current-error-port))))
336 ((ly:output-def-lookup bookpaper 'page-make-stencil)
340 (node-page-number node)
341 (eq? node best-break-node)))