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 #:score))
143 (define INFINITY 1e9)
145 (define (line-number line)
147 (ly:paper-line-number line)))
149 (define (line-height line)
151 (ly:paper-line-height line)))
153 (define (node-line-number node)
155 (line-number (node-line node))))
157 (define (node-break-score node)
158 (let ((line (node-line node)))
160 (ly:paper-line-break-score line))))
162 (define (make-node prev line page score)
163 (make <break-node> #:prev prev #:line line #:page page #:score score))
165 (define MAX-CRAMP 0.05)
167 (define-public (ly:optimal-page-breaks lines book-height text-height
168 first-diff last-diff)
170 ;; FIXME: may need some tweaking: square, cubic
171 (define (height-score available used)
172 (let* ((empty (- available used))
173 (norm-empty (* empty (/ 100 available))))
175 (if (> (* -1 (/ empty available)) MAX-CRAMP)
176 ;; cannot fill more than MAX-CRAMP
178 ;; overfull page is still worse by a power
179 (* -1 norm-empty norm-empty norm-empty))
180 (* norm-empty norm-empty))))
182 (define (page-height page-number page-count)
183 (let ((h text-height))
184 (if (= page-number 1)
185 (set! h (+ h first-diff)))
186 (if (= page-number page-count)
187 ;;(> page-number (/ book-height text-height))
188 (set! h (+ h last-diff)))
191 (define (cumulative-height lines)
192 (apply + (map line-height lines)))
194 (define (get-path node)
197 (cons node (get-path (node-prev node)))))
199 (define (add-scores . lst)
200 (if (null? (filter (lambda (x) (> 0 x)) lst))
204 (define (density-variance nodes)
205 (define (sqr x) (* x x))
206 (define (density node)
207 (let ((p (page-height (node-page node) (node-page (car nodes))))
208 (h (node-height node)))
209 (if (and p h) (* (- p h) (/ h 100)) 0)))
210 (let* ((densities (map density nodes))
211 (mean (/ (apply + densities) (length densities)))
212 (diff (map (lambda (x) (- x mean)) densities))
213 (var (map sqr diff)))
216 (format (current-error-port) "\nDENSITIES")
218 (format (current-error-port) "densities: ~S\n" densities)
219 (format (current-error-port) "mean: ~S\n" mean)
220 (format (current-error-port) "diff: ~S\n" diff)
221 (format (current-error-port) "density-var: ~S\n" var)))
224 (define (walk-paths best node lines nodes paths)
225 (let* ((height (cumulative-height lines))
226 (next-page (+ (if (null? paths) 0 (node-page (car paths))) 1))
227 (page (page-height (node-page node) next-page)))
228 (set! (node-height node) height)
229 (let* ((break-score (node-break-score node))
230 (density-score (if (null? paths) 0
231 (* 0 (density-variance
232 (get-path (car paths))))))
233 (page-score (height-score page height))
234 (this-score (add-scores page-score break-score density-score))
235 (path-score (if (null? paths) 0 (node-score (car paths))))
236 (score (add-scores path-score this-score)))
238 (if (and (>= score 0)
240 (or (< score (node-score best))
241 (= (node-score best) -1)))
243 (set! (node-score best) score)
244 (set! (node-page best) next-page)
245 (set! (node-height best) height)
246 (set! (node-prev best) node)))
250 (walk-paths best (car paths)
251 (cons (node-line node) lines)
252 (cdr nodes) (cdr paths))))))
254 (define (walk-lines lines nodes paths)
255 (if (null? (cdr lines))
257 (let* ((prev (node-prev (car nodes)))
258 (this (make-node prev (car lines) 0 INFINITY))
259 (next (make-node this (cadr lines) 0 0)))
260 (let ((break (walk-paths this (car nodes) '() (cdr nodes) paths)))
261 (walk-lines (cdr lines) (cons next nodes) (cons break paths))))))
263 (let* ((dummy (make-node '() '() 0 0))
264 (this (make-node dummy (car lines) 0 0))
265 (result (walk-lines lines (list this dummy) (list dummy)))
266 (path (get-path (car result)))
267 ;; CDR: junk dummy node
268 (breaks (cdr (reverse (map node-line-number path)))))
270 (format (current-error-port) "ESTIMATE: ~S\n"
271 (/ book-height text-height))
272 (format (current-error-port) "breaks: ~S\n" breaks)
273 (force-output (current-error-port))
274 (list->vector breaks)))