1 ;;;; page-layout.scm -- page layout functions
3 ;;;; source file of the GNU LilyPond music typesetter
5 ;;;; (c) 2004 Jan Nieuwenhuizen <janneke@gnu.org>
8 (define-public (page-properties paper)
9 (list (append `((linewidth . ,(ly:paper-get-number
11 (ly:output-def-lookup paper 'text-font-defaults))))
13 (define-public (plain-header paper page-number)
14 (let ((props (page-properties paper) ))
15 (interpret-markup paper props
17 ("" #:bold (number->string page-number))))))
19 (define-public (plain-footer paper page-number)
20 (let ((props (page-properties paper)))
22 (interpret-markup paper props
23 (markup #:fill-line ("" (number->string page-number))))))
27 (string-append "Engraved by LilyPond (version " (lilypond-version) ")"))
29 (define-public (TAGLINE-or-tagline-from-header paper scopes)
30 (let* ((props (page-properties paper))
31 (tagline-var (ly:modules-lookup scopes 'tagline))
32 (tagline (if (markup? tagline-var) tagline-var TAGLINE)))
34 (cond ((string? tagline)
35 (if (not (equal? tagline ""))
36 (interpret-markup paper props
37 (markup #:fill-line (tagline "")))))
38 ((markup? tagline) (interpret-markup paper props tagline)))))
40 (define-public (copyright-from-header paper scopes)
41 (let ((props (page-properties paper))
42 (copyright (ly:modules-lookup scopes 'copyright)))
44 (cond ((string? copyright)
45 (if (not (equal? copyright ""))
46 (interpret-markup paper props
47 (markup #:fill-line (copyright "")))))
48 ((markup? copyright) (interpret-markup paper props copyright)))))
51 ;;; optimal page breaking
53 ;;; This is not optimal page breaking, this is optimal distribution of
54 ;;; lines over pages; line breaks are a given.
58 ;;; + \pagebreak, \nopagebreak
60 ;;; - short circut SCORE=-1 (dismiss path)
64 (use-modules (oop goops describe))
66 (define-class <break-node> ()
67 (prev #:init-value '() #:accessor node-prev #:init-keyword #:prev)
68 (line #:init-value 'barf #:accessor node-line #:init-keyword #:line)
69 (page #:init-value 0 #:accessor node-page #:init-keyword #:page)
70 (score #:init-value 0 #:accessor node-score #:init-keyword #:score)
71 (height #:init-value 0 #:accessor node-height #:init-keyword #:height))
75 (define (robust-paper-line-number line)
77 (ly:paper-line-number line)))
79 (define (robust-line-height line)
81 (ly:paper-line-height line)))
83 (define (robust-line-number node)
85 (robust-paper-line-number (node-line node))))
87 (define (robust-break-score node)
88 (let ((line (node-line node)))
90 (ly:paper-line-break-score line))))
92 (define (make-node prev line page score . height)
93 (make <break-node> #:prev prev #:line line #:page page #:score score
94 #:height (if (null? height) 0 (car height))))
97 (define MAX-CRAMP 0.05)
99 (define-public (ly:optimal-page-breaks lines
102 first-diff last-diff)
104 ;; FIXME: may need some tweaking: square, cubic
105 (define (height-score available used)
106 (let* ((empty (- available used))
107 (norm-empty (* empty (/ 100 available))))
109 (if (> (* -1 (/ empty available)) MAX-CRAMP)
110 ;; cannot fill more than MAX-CRAMP
112 ;; overfull page is still worse by a power
113 ;; -- which means it never happens
114 ;; let's try a factor 2
115 ;;(* -1 norm-empty norm-empty norm-empty))
116 (* 2 norm-empty norm-empty))
117 (* norm-empty norm-empty))))
119 (define (page-height page-number page-count)
120 (let ((h text-height))
121 (if (= page-number 1)
122 (set! h (+ h first-diff)))
123 (if (= page-number page-count)
124 (set! h (+ h last-diff)))
127 (define (cumulative-height lines)
128 (apply + (map robust-line-height lines)))
130 (define (get-path node)
131 (if (null? node) '() (cons node (get-path (node-prev node)))))
133 (define (add-scores . lst)
134 (if (null? (filter (lambda (x) (> 0 x)) lst)) (apply + lst) -1))
136 (define (density-variance nodes)
137 (define (sqr x) (* x x))
138 (define (density node)
139 (let ((p (page-height (node-page node) (node-page (car nodes))))
140 (h (node-height node)))
141 (if (and p h) (/ h p) 0)))
143 (let* ((height-nodes (reverse
144 ;; reverse makes for handier debugging
145 (filter (lambda (x) (> (node-height x) 0)) nodes)))
146 (densities (map density height-nodes))
147 (p-heights (map (lambda (x) (page-height (node-page x)
148 (node-page (car nodes))))
150 (heights (map node-height height-nodes))
151 (mean (/ (apply + densities) (length densities)))
152 (diff (map (lambda (x) (- x mean)) densities))
153 (var (map sqr (map (lambda (x) (* (car p-heights) x)) diff))))
156 (define (walk-paths best node lines nodes paths)
157 (let* ((height (cumulative-height lines))
158 (next-page (+ (if (null? paths) 0 (node-page (car paths))) 1))
159 (page (page-height (node-page node) next-page))
160 (hh (make-node '() (node-line node) 0 0 height))
161 (break-score (robust-break-score node))
162 (density-score (if (null? paths) 0
163 ;; TODO: find out why we need density
164 ;; use other height-score parameters?
165 ;; See: input/test/page-breaks.ly
166 (* 1 (density-variance
167 (cons hh (get-path (car paths)))))))
168 (page-score (height-score page height))
169 (this-score (add-scores page-score break-score density-score))
170 (path-score (if (null? paths) 0 (node-score (car paths))))
171 (score (add-scores path-score this-score)))
173 (if (and (>= score 0)
174 (or (<= score (node-score best))
175 (= (node-score best) -1)))
177 (set! (node-score best) score)
178 (set! (node-page best) next-page)
179 (set! (node-height best) height)
180 (set! (node-prev best) (car paths))))
182 (if (or (null? nodes)
184 (and (= path-score -1)
185 (> (- (/ height page) 1) MAX-CRAMP)))
187 (walk-paths best (car nodes)
188 (cons (node-line (car paths)) lines)
189 (cdr nodes) (cdr paths)))))
191 (define (walk-lines lines nodes paths)
192 (if (null? (cdr lines))
194 (let* ((prev (node-prev (car nodes)))
195 (this (make-node prev (car lines) 0 INFINITY))
196 (next (make-node this (cadr lines) 0 0))
197 (best (walk-paths this prev (list (node-line (car nodes)))
198 (cddr nodes) paths)))
199 (walk-lines (cdr lines) (cons next nodes) (cons best paths)))))
201 (let* ((dummy (make-node '() '() 0 0))
202 (this (make-node dummy (car lines) 0 0))
203 (result (walk-lines lines (list this dummy) (list dummy)))
204 (path (get-path (car result)))
205 ;; CDR: junk dummy node
206 (breaks (cdr (reverse (map robust-line-number path)))))
208 (if (ly:get-option 'verbose)
210 (format (current-error-port) "breaks: ~S\n" breaks)
211 (force-output (current-error-port))))
213 ;; TODO: if solution is bad return no breaks and revert to
215 (list->vector breaks)))
221 (define-public (default-book-title paper scopes)
222 "Generate book title from header strings."
226 (let ((x (ly:modules-lookup scopes sym)))
227 (if (markup? x) x "")))
229 (let ((props (page-properties paper)))
235 (#:override '(baseline-skip . 4)
238 (#:normalsize (get 'dedication))
240 (#:huge #:bigger #:bigger #:bigger #:bigger #:bold (get 'title))
241 #:override '(baseline-skip . 3)
244 (#:large #:bigger #:bigger #:bold (get 'subtitle))
245 #:fill-line (#:bigger #:bigger #:bold (get 'subsubtitle)))
246 #:override '(baseline-skip . 5)
248 #:override '(baseline-skip . 2.5)
251 (#:bigger (get 'poet) #:large #:bigger #:caps (get 'composer))
252 #:fill-line (#:bigger (get 'texttranslator) #:bigger (get 'opus))
254 (#:bigger (get 'meter) #:bigger (get 'arranger))
256 #:fill-line (#:large #:bigger (get 'instrument))
258 #:fill-line (#:large #:bigger #:caps (get 'piece) ""))))))))
260 (define-public (default-user-title paper markup)
261 "Generate book title from header markup."
263 (let ((props (page-properties paper))
264 (baseline-skip (chain-assoc-get 'baseline-skip props 2)) )
265 (stack-lines DOWN 0 BASELINE-SKIP
266 (list (interpret-markup paper props markup))))))
268 (define-public (default-score-title paper scopes)
269 "Generate score title from header strings."
272 (let ((x (ly:modules-lookup scopes sym)))
273 (if (and x (not (unspecified? x))) x "")))
275 (let ((props (page-properties paper)))
281 (#:override '(baseline-skip . 4)
285 #:fill-line (#:large #:bigger #:caps (get 'piece) "")))))))