1 ;;;; page-layout.scm -- page breaking and page layout
3 ;;;; source file of the GNU LilyPond music typesetter
5 ;;;; (c) 2004--2005 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 (force #:init-value 0 #:accessor node-force #:init-keyword #:force)
18 (penalty #:init-value 0 #:accessor node-penalty #:init-keyword #:penalty)
19 (configuration #:init-value '() #:accessor node-configuration #:init-keyword #:configuration)
20 (lines #:init-value 0 #:accessor node-lines #:init-keyword #:lines))
22 (define-method (display (node <optimally-broken-page-node>) port)
23 (map (lambda (x) (display x port))
25 "Page " (node-page-number node)
26 " Lines: " (node-lines node)
27 " Penalty " (node-penalty node)
30 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
33 (string-append "Engraved by LilyPond (version " (lilypond-version) ")"))
35 (define (page-headfoot layout scopes number sym sepsym dir last?)
36 "Create a stencil including separating space."
37 (let* ((header-proc (ly:output-def-lookup layout sym))
38 (sep (ly:output-def-lookup layout sepsym))
39 (stencil (ly:make-stencil "" '(0 . 0) '(0 . 0)))
41 (if (procedure? header-proc)
42 (header-proc layout scopes number last?)
45 (if (and (number? sep)
46 (ly:stencil? head-stencil)
47 (not (ly:stencil-empty? head-stencil)))
49 (ly:stencil-combine-at-edge
50 stencil Y dir head-stencil
55 (define-public (default-page-music-height layout scopes number last?)
56 "Printable area for music and titles; matches default-page-make-stencil."
57 (let* ((h (- (ly:output-def-lookup layout 'vsize)
58 (ly:output-def-lookup layout 'topmargin)
59 (ly:output-def-lookup layout 'bottommargin)))
60 (head (page-headfoot layout scopes number 'make-header 'headsep UP last?))
61 (foot (page-headfoot layout scopes number 'make-footer 'footsep DOWN last?))
63 (- h (if (ly:stencil? head)
64 (interval-length (ly:stencil-extent head Y))
66 (if (ly:stencil? foot)
67 (interval-length (ly:stencil-extent foot Y))
70 ;; (display (list "\n available" available head foot))
73 (define-public (default-page-make-stencil
74 lines offsets layout scopes number last?)
75 "Construct a stencil representing the page from LINES.
77 Offsets is a list of increasing numbers. They must be negated to
80 (let* ((topmargin (ly:output-def-lookup layout 'topmargin))
82 ;; TODO: naming vsize/hsize not analogous to TeX.
84 (vsize (ly:output-def-lookup layout 'vsize))
85 (hsize (ly:output-def-lookup layout 'hsize))
87 (system-separator-markup (ly:output-def-lookup layout 'systemSeparatorMarkup))
88 (system-separator-stencil (if (markup? system-separator-markup)
89 (interpret-markup layout
90 (page-properties layout)
91 system-separator-markup)
93 (lmargin (ly:output-def-lookup layout 'leftmargin))
94 (leftmargin (if lmargin
97 (ly:output-def-lookup layout 'linewidth)) 2)))
99 (rightmargin (ly:output-def-lookup layout 'rightmargin))
100 (bottom-edge (- vsize
101 (ly:output-def-lookup layout 'bottommargin)))
103 (head (page-headfoot layout scopes number 'make-header 'headsep UP last?))
104 (foot (page-headfoot layout scopes number 'make-footer 'footsep DOWN last?))
106 (head-height (if (ly:stencil? head)
107 (interval-length (ly:stencil-extent head Y))
110 (height-proc (ly:output-def-lookup layout 'page-music-height))
112 (page-stencil (ly:make-stencil '()
113 (cons leftmargin hsize)
114 (cons (- topmargin) 0)))
117 (add-to-page (lambda (stencil y)
119 (ly:stencil-add page-stencil
120 (ly:stencil-translate-axis stencil
121 (- 0 head-height y topmargin) Y)))))
122 (add-system (lambda (stencil-position)
124 ((system (car stencil-position))
125 (stencil (ly:paper-system-stencil system))
126 (y (cadr stencil-position))
127 (is-title (ly:paper-system-title?
128 (car stencil-position))))
130 (add-to-page stencil y)
131 (if (and (ly:stencil? system-separator-stencil)
133 (not (ly:paper-system-title? system))
134 (not (ly:paper-system-title? last-system)))
135 (add-to-page system-separator-stencil
137 (car (ly:paper-system-staff-extents last-system)))
139 (cdr (ly:paper-system-staff-extents system))))))
140 (set! last-system system)
145 "leftmargin" leftmargin "rightmargin" rightmargin)))
147 (set! page-stencil (ly:stencil-combine-at-edge
148 page-stencil Y DOWN head 0. 0.))
150 (map add-system (zip lines offsets))
151 (if (ly:stencil? foot)
155 (ly:stencil-translate
159 (- (car (ly:stencil-extent foot Y)))))))))
161 (ly:stencil-translate page-stencil (cons leftmargin 0))))
163 ;;; optimal page breaking
165 ;;; This is not optimal page breaking, this is optimal distribution of
166 ;;; lines over pages; line breaks are a given.
171 ;; - separate function for word-wrap style breaking?
172 ;; - raggedbottom? raggedlastbottom?
174 (define-public (ly:optimal-page-breaks
176 "Return pages as a list starting with 1st page. Each page is a list
180 (define MAXPENALTY 1e9)
181 (define paper (ly:paper-book-paper paper-book))
182 (define scopes (ly:paper-book-scopes paper-book))
184 (define (page-height page-number last?)
185 (let ((p (ly:output-def-lookup paper 'page-music-height)))
188 (p paper scopes page-number last?)
191 (define (get-path node done)
192 "Follow NODE.PREV, and return as an ascending list of pages. DONE
193 is what have collected so far, and has ascending page numbers."
195 (if (is-a? node <optimally-broken-page-node>)
196 (get-path (node-prev node) (cons node done))
199 (define (combine-penalties force user best-paths)
200 (let* ((prev-force (if (null? best-paths)
202 (node-force (car best-paths))))
203 (prev-penalty (if (null? best-paths)
205 (node-penalty (car best-paths))))
206 (inter-system-space (ly:output-def-lookup paper 'betweensystemspace))
207 (force-equalization-factor 0.3)
208 (relative-force (/ force inter-system-space))
209 (abs-relative-force (abs relative-force)))
212 (+ (* abs-relative-force (+ abs-relative-force 1))
214 (* force-equalization-factor (/ (abs (- prev-force force)) inter-system-space))
217 (define (space-systems page-height lines ragged?)
218 (let* ((inter-system-space
219 (ly:output-def-lookup paper 'betweensystemspace))
220 (system-vector (list->vector
222 (if (= (length lines) 1)
227 (append (map ly:paper-system-staff-extents lines)
228 (if (= (length lines) 1)
235 (lambda (sys) (ly:paper-system-extent sys Y)) lines)
236 (if (= (length lines) 1)
239 (no-systems (vector-length real-extents))
240 (topskip (interval-end (vector-ref real-extents 0)))
241 (space-left (- page-height
242 (apply + (map interval-length (vector->list real-extents)))))
244 (space (- page-height
246 (- (interval-start (vector-ref real-extents (1- no-systems))))))
248 (fixed-dist (ly:output-def-lookup paper 'betweensystempadding))
251 (let* ((this-system-ext (vector-ref staff-extents idx))
252 (next-system-ext (vector-ref staff-extents (1+ idx)))
253 (fixed (max 0 (- (+ (interval-end next-system-ext)
255 (interval-start this-system-ext))))
256 (title1? (and (vector-ref system-vector idx)
257 (ly:paper-system-title? (vector-ref system-vector idx))))
259 (vector-ref system-vector (1+ idx))
260 (ly:paper-system-title? (vector-ref system-vector (1+ idx)))))
263 ((and title2? title1?)
264 (ly:output-def-lookup paper 'betweentitlespace))
266 (ly:output-def-lookup paper 'aftertitlespace))
268 (ly:output-def-lookup paper 'beforetitlespace))
269 (else inter-system-space))
271 (hooke (/ 1 (- ideal fixed))))
272 (list ideal hooke))))
274 (springs (map calc-spring (iota (1- no-systems))))
277 (let* ((this-system-ext (vector-ref real-extents idx))
278 (next-system-ext (vector-ref real-extents (1+ idx)))
279 (distance (max (- (+ (interval-end next-system-ext)
281 (interval-start this-system-ext)
283 (entry (list idx (1+ idx) distance)))
285 (rods (map calc-rod (iota (1- no-systems))))
287 ;; we don't set ragged based on amount space left.
288 ;; raggedbottomlast = ##T is much more predictable
289 (result (ly:solve-spring-rod-problem
301 (display (list "\n# systems: " no-systems
302 "\nreal-ext" real-extents "\nstaff-ext" staff-extents
303 "\ninterscore" inter-system-space
304 "\nspace-letf" space-left
305 "\nspring,rod" springs rods
308 "\npage-height" page-height
312 "\npositions" positions "\n"))))
314 (cons force positions)))
316 (define (walk-paths done-lines best-paths current-lines last? current-best)
317 "Return the best optimal-page-break-node that contains
318 CURRENT-LINES. DONE-LINES.reversed ++ CURRENT-LINES is a consecutive
319 ascending range of lines, and BEST-PATHS contains the optimal breaks
320 corresponding to DONE-LINES.
322 CURRENT-BEST is the best result sofar, or #f."
324 (let* ((this-page-num (if (null? best-paths)
325 (ly:output-def-lookup paper 'firstpagenumber)
326 (1+ (node-page-number (car best-paths)))))
328 (ragged-all? (eq? #t (ly:output-def-lookup paper 'raggedbottom)))
329 (ragged-last? (eq? #t (ly:output-def-lookup paper 'raggedlastbottom)))
330 (ragged? (or ragged-all?
333 (page-height (page-height this-page-num last?))
334 (vertical-spacing (space-systems page-height current-lines ragged?))
335 (satisfied-constraints (car vertical-spacing))
336 (force (if satisfied-constraints
337 (if (and last? ragged-last?)
339 satisfied-constraints)
341 (positions (cdr vertical-spacing))
342 (user-nobreak-penalties
344 (apply + (filter negative?
345 (map ly:paper-system-break-before-penalty
346 (cdr current-lines))))))
349 (max (ly:paper-system-break-before-penalty (car current-lines)) 0.0)
350 user-nobreak-penalties))
351 (total-penalty (combine-penalties
358 (< total-penalty (node-penalty current-best))))
359 (new-best (if better?
360 (make <optimally-broken-page-node>
361 #:prev (if (null? best-paths)
364 #:lines current-lines
365 #:pageno this-page-num
367 #:configuration positions
368 #:penalty total-penalty)
374 "\nuser pen " user-penalty
375 "\nsatisfied-constraints" satisfied-constraints
376 "\nlast? " last? "ragged?" ragged?
377 "\nbetter? " better? " total-penalty " total-penalty "\n"
378 "\nconfig " positions
380 "\nlines: " current-lines "\n")))
383 (display (list "\nnew-best is " (node-lines new-best)
385 (if (null? best-paths)
387 (node-lines (car best-paths))))))
389 (if (and (pair? done-lines)
390 ;; if this page is too full, adding another line won't help
391 satisfied-constraints)
392 (walk-paths (cdr done-lines) (cdr best-paths)
393 (cons (car done-lines) current-lines)
397 (define (walk-lines done best-paths todo)
398 "Return the best page breaking as a single
399 <optimal-page-break-node> for optimally breaking TODO ++
400 DONE.reversed. BEST-PATHS is a list of break nodes corresponding to
404 (let* ((this-line (car todo))
405 (last? (null? (cdr todo)))
406 (next (walk-paths done best-paths (list this-line) last? #f)))
408 ;; (display "\n***************")
409 (walk-lines (cons this-line done)
410 (cons next best-paths)
413 (define (line-number node)
414 (ly:paper-system-number (car (node-lines node))))
416 (let* ((best-break-node (walk-lines '() '() lines))
417 (break-nodes (get-path best-break-node '())))
419 (if #f; (ly:get-option 'verbose)
422 "\nbreaks: " (map line-number break-nodes))
423 "\nsystems " (map node-lines break-nodes)
424 "\npenalties " (map node-penalty break-nodes)
425 "\nconfigs " (map node-configuration break-nodes))))
429 ((ly:output-def-lookup paper 'page-make-stencil)
431 (node-configuration node)
434 (node-page-number node)
435 (eq? node best-break-node)))