1 ;;;; page-layout.scm -- page layout functions
3 ;;;; source file of the GNU LilyPond music typesetter
5 ;;;; (c) 2004 Jan Nieuwenhuizen <janneke@gnu.org>
7 (define (ly:modules-lookup modules sym)
8 (let ((v (module-variable (car modules) sym)))
9 (if (and v (variable-bound? v) (variable-ref v))
11 (if (module? (cdr modules)) (ly:modules-lookup (cdr modules) sym)))))
13 (define (page-properties paper)
14 (list (append `((linewidth . ,(ly:paper-get-number
16 (ly:paper-lookup paper 'text-font-defaults))))
18 (define-public (book-title paper scopes)
19 "Generate book title from header strings."
22 (let ((x (ly:modules-lookup scopes sym)))
23 (if (and x (not (unspecified? x))) x "")))
25 (let ((props (page-properties paper)))
31 (#:override '(baseline-skip . 4)
34 (#:normalsize (get 'dedication))
36 (#:huge #:bigger #:bigger #:bigger #:bigger #:bold (get 'title))
37 #:override '(baseline-skip . 3)
40 (#:large #:bigger #:bigger #:bold (get 'subtitle))
41 #:fill-line (#:bigger #:bigger #:bold (get 'subsubtitle)))
42 #:override '(baseline-skip . 5)
44 #:override '(baseline-skip . 2.5)
47 (#:bigger (get 'poet) #:large #:bigger #:caps (get 'composer))
48 #:fill-line (#:bigger (get 'texttranslator) #:bigger (get 'opus))
50 (#:bigger (get 'meter) #:bigger (get 'arranger))
52 #:fill-line (#:large #:bigger (get 'instrument))
54 #:fill-line (#:large #:bigger #:caps (get 'piece) ""))))))))
56 (define-public (user-title paper markup)
57 "Generate book title from header markup."
59 (let ((props (page-properties paper))
60 (baseline-skip (chain-assoc-get 'baseline-skip props 2)) )
61 (stack-lines DOWN 0 BASELINE-SKIP
62 (list (interpret-markup paper props markup))))))
64 (define-public (score-title paper scopes)
65 "Generate score title from header strings."
68 (let ((x (ly:modules-lookup scopes sym)))
69 (if (and x (not (unspecified? x))) x "")))
71 (let ((props (page-properties paper)))
77 (#:override '(baseline-skip . 4)
81 #:fill-line (#:large #:bigger #:caps (get 'piece) "")))))))
83 (define-public (make-header paper page-number)
84 (let ((props (page-properties paper) ))
85 (interpret-markup paper props
87 ("" #:bold (number->string page-number))))))
89 (define-public (make-footer paper page-number)
90 (let ((props (page-properties paper)))
92 (interpret-markup paper props
93 (markup #:fill-line ("" (number->string page-number))))))
97 (string-append "Engraved by LilyPond (version " (lilypond-version) ")"))
99 (define-public (make-tagline paper scopes)
100 (let* ((props (page-properties paper))
101 (tagline-var (ly:modules-lookup scopes 'tagline))
102 (tagline (if (markup? tagline-var) tagline-var TAGLINE)))
104 (cond ((string? tagline)
105 (if (not (equal? tagline ""))
106 (interpret-markup paper props
107 (markup #:fill-line (tagline "")))))
108 ((markup? tagline) (interpret-markup paper props tagline)))))
110 (define-public (make-copyright paper scopes)
111 (let ((props (page-properties paper))
112 (copyright (ly:modules-lookup scopes 'copyright)))
114 (cond ((string? copyright)
115 (if (not (equal? copyright ""))
116 (interpret-markup paper props
117 (markup #:fill-line (copyright "")))))
118 ((markup? copyright) (interpret-markup paper props copyright)))))
121 ;;; optimal page breaking
123 ;;; This is not optimal page breaking, this is optimal distribution of
124 ;;; lines over pages; line breaks are a given.
128 ;;; + \pagebreak, \nopagebreak
130 ;;; - short circut SCORE=-1 (dismiss path)
131 ;;; - density scoring
134 (use-modules (oop goops describe))
136 (define-class <break-node> ()
137 (prev #:init-value '() #:accessor node-prev #:init-keyword #:prev)
138 (line #:init-value 'barf #:accessor node-line #:init-keyword #:line)
139 (page #:init-value 0 #:accessor node-page #:init-keyword #:page)
140 (score #:init-value 0 #:accessor node-score #:init-keyword #:score)
141 (height #:init-value 0 #:accessor node-height #:init-keyword #:height))
143 (define INFINITY 1e9)
145 (define (robust-paper-line-number line)
147 (ly:paper-line-number line)))
149 (define (robust-line-height line)
151 (ly:paper-line-height line)))
153 (define (robust-line-number node)
155 (robust-paper-line-number (node-line node))))
157 (define (robust-break-score node)
158 (let ((line (node-line node)))
160 (ly:paper-line-break-score line))))
162 (define (make-node prev line page score . height)
163 (make <break-node> #:prev prev #:line line #:page page #:score score
164 #:height (if (null? height) 0 (car height))))
167 (define MAX-CRAMP 0.05)
169 (define-public (ly:optimal-page-breaks lines book-height text-height
170 first-diff last-diff)
172 ;; FIXME: may need some tweaking: square, cubic
173 (define (height-score available used)
174 (let* ((empty (- available used))
175 (norm-empty (* empty (/ 100 available))))
177 (if (> (* -1 (/ empty available)) MAX-CRAMP)
178 ;; cannot fill more than MAX-CRAMP
180 ;; overfull page is still worse by a power
181 ;; -- which means it never happens
182 ;; let's try a factor 2
183 ;;(* -1 norm-empty norm-empty norm-empty))
184 (* 2 norm-empty norm-empty))
185 (* norm-empty norm-empty))))
187 (define (page-height page-number page-count)
188 (let ((h text-height))
189 (if (= page-number 1)
190 (set! h (+ h first-diff)))
191 (if (= page-number page-count)
192 ;;(> page-number (/ book-height text-height))
193 (set! h (+ h last-diff)))
196 (define (cumulative-height lines)
197 (apply + (map robust-line-height lines)))
199 (define (get-path node)
200 (if (null? node) '() (cons node (get-path (node-prev node)))))
202 (define (add-scores . lst)
203 (if (null? (filter (lambda (x) (> 0 x)) lst)) (apply + lst) -1))
205 (define (density-variance nodes)
206 (define (sqr x) (* x x))
207 (define (density node)
208 (let ((p (page-height (node-page node) (node-page (car nodes))))
209 (h (node-height node)))
210 (if (and p h) (/ h p) 0)))
212 (let* ((height-nodes (reverse
213 ;; reverse makes for handier debugging
214 (filter (lambda (x) (> (node-height x) 0)) nodes)))
215 (densities (map density height-nodes))
216 (p-heights (map (lambda (x) (page-height (node-page x)
217 (node-page (car nodes))))
219 (heights (map node-height height-nodes))
220 (mean (/ (apply + densities) (length densities)))
221 (diff (map (lambda (x) (- x mean)) densities))
222 (var (map sqr (map (lambda (x) (* (car p-heights) x)) diff))))
225 (define (walk-paths best node lines nodes paths)
226 (let* ((height (cumulative-height lines))
227 (next-page (+ (if (null? paths) 0 (node-page (car paths))) 1))
228 (page (page-height (node-page node) next-page))
229 (hh (make-node '() (node-line node) 0 0 height))
230 (break-score (robust-break-score node))
231 (density-score (if (null? paths) 0
232 ;; TODO: find out why we need density
233 ;; use other height-score parameters?
234 ;; See: input/test/page-breaks.ly
235 (* 1 (density-variance
236 (cons hh (get-path (car paths)))))))
237 (page-score (height-score page height))
238 (this-score (add-scores page-score break-score density-score))
239 (path-score (if (null? paths) 0 (node-score (car paths))))
240 (score (add-scores path-score this-score)))
242 (if (and (>= score 0)
243 (or (<= score (node-score best))
244 (= (node-score best) -1)))
246 (set! (node-score best) score)
247 (set! (node-page best) next-page)
248 (set! (node-height best) height)
249 (set! (node-prev best) (car paths))))
251 (if (or (null? nodes)
253 (and (= path-score -1)
254 (> (- (/ height page) 1) MAX-CRAMP)))
256 (walk-paths best (car nodes)
257 (cons (node-line (car paths)) lines)
258 (cdr nodes) (cdr paths)))))
260 (define (walk-lines lines nodes paths)
261 (if (null? (cdr lines))
263 (let* ((prev (node-prev (car nodes)))
264 (this (make-node prev (car lines) 0 INFINITY))
265 (next (make-node this (cadr lines) 0 0))
266 (best (walk-paths this prev (list (node-line (car nodes)))
267 (cddr nodes) paths)))
268 (walk-lines (cdr lines) (cons next nodes) (cons best paths)))))
270 (let* ((dummy (make-node '() '() 0 0))
271 (this (make-node dummy (car lines) 0 0))
272 (result (walk-lines lines (list this dummy) (list dummy)))
273 (path (get-path (car result)))
274 ;; CDR: junk dummy node
275 (breaks (cdr (reverse (map robust-line-number path)))))
277 (format (current-error-port) "ESTIMATE: ~S\n"
278 (/ book-height text-height))
279 (format (current-error-port) "breaks: ~S\n" breaks)
280 ;; TODO: if solution is bad return no breaks and revert to
282 (force-output (current-error-port))
283 (list->vector breaks)))