? scm/layout-page-dump.scm
Index: ChangeLog
===================================================================
RCS file: /cvsroot/lilypond/lilypond/ChangeLog,v
retrieving revision 1.5167
diff -u -r1.5167 ChangeLog
--- ChangeLog	14 Jul 2006 09:49:40 -0000	1.5167
+++ ChangeLog	14 Jul 2006 18:44:33 -0000
@@ -1,3 +1,16 @@
+2006-07-14  Nicolas Sceaux  <address@hidden>
+
+	* scm/layout-page-layout.scm: Define module, tidy code, use more
+	functions iso. a single big one.
+
+	* scm/layout-page-dump.scm: move page dump functions used in two
+	pass spacing to this file. Define module.
+
+	* scm/lily.scm (ly:load): don't load layout-page-layout.scm
+	 (separate module)
+
+	* ly/paper-defaults.ly: use module layout-page-layout.
+
 2006-07-14  Erik Sandberg  <address@hidden>
 
 	* lily/music.cc: Revised MusicEvent event class. It now contains
Index: ly/paper-defaults.ly
===================================================================
RCS file: /cvsroot/lilypond/lilypond/ly/paper-defaults.ly,v
retrieving revision 1.24
diff -u -r1.24 paper-defaults.ly
--- ly/paper-defaults.ly	16 Mar 2006 14:39:46 -0000	1.24
+++ ly/paper-defaults.ly	14 Jul 2006 18:44:35 -0000
@@ -1,5 +1,5 @@
 \version "2.7.39"
-
+#(use-modules (scm layout-page-layout))
 \paper {
 
     %%%% WARNING
Index: scm/layout-page-layout.scm
===================================================================
RCS file: /cvsroot/lilypond/lilypond/scm/layout-page-layout.scm,v
retrieving revision 1.17
diff -u -r1.17 layout-page-layout.scm
--- scm/layout-page-layout.scm	27 May 2006 01:07:55 -0000	1.17
+++ scm/layout-page-layout.scm	14 Jul 2006 18:44:36 -0000
@@ -1,148 +1,97 @@
-;;;; page-layout.scm -- page breaking and page layout
+;;;; layout-page-layout.scm -- page breaking and page layout
 ;;;;
 ;;;;  source file of the GNU LilyPond music typesetter
 ;;;;
 ;;;; (c) 2004--2006 Jan Nieuwenhuizen <address@hidden>
 ;;;;          Han-Wen Nienhuys <address@hidden>
 
-(use-modules (oop goops describe)
-	     (oop goops)
-	     (scm paper-system)
-	     (scm page)
-	     )
-
-
-(define (write-page-breaks pages) 
-  "Dump page breaks"
-
-  (define tweaks (make-hash-table 23))
-
-  (define (record what property-pairs)
-    (let*
-	((key (ly:output-def-lookup (ly:grob-layout what)
-				    'tweak-key
-				    "tweaks"
-				    ))
-	 (when (ly:grob-property what 'when))
-	 )
-
-      (if (not (hash-ref tweaks key))
-	  (hash-set! tweaks key '()))
-
-      (hash-set! tweaks key
-		 (acons when property-pairs
-			(hash-ref tweaks key)))
-      
-      ))
-
-  (define (graceless-moment mom)
-    (ly:make-moment
-     (ly:moment-main-numerator mom)
-     (ly:moment-main-denominator mom)
-     0 0))
-
-  (define (moment->skip mom)
-    (let*
-	((main (if (> (ly:moment-main-numerator mom) 0)
-		   (format "\\skip 1*~a/~a"
-			   (ly:moment-main-numerator mom)
-			   (ly:moment-main-denominator mom))
-		   ""))
-	 (grace (if (< (ly:moment-grace-numerator mom) 0)
-		    (format "\\grace { \\skip 1*~a/~a }"
-			    (- (ly:moment-grace-numerator mom))
-			    (ly:moment-grace-denominator mom))
-		    "")))
-
-      (format "~a~a" main grace)))
-    
-  (define (dump-tweaks out-port tweak-list last-moment)
-    (if (not (null? tweak-list))
-	(let*
-	    ((now (caar tweak-list))
-	     (diff (ly:moment-sub now last-moment))
-	     (these-tweaks (cdar tweak-list))
-	     (skip (moment->skip diff))
-	     (line-break-str (if (assoc-get 'line-break these-tweaks #f)
-				 "\\break\n"
-				 ""))
-	     (page-break-str (if (assoc-get 'page-break these-tweaks #f)
-				 "\\pageBreak\n"
-				 ""))
-	     (space-tweaks (format "\\spacingTweaks #'~a\n"
-				   (with-output-to-string
-				     (lambda ()
-				       (pretty-print
-				   
-					(assoc-get 'spacing-parameters these-tweaks '()))))
-				     ))
-	     (base (format "~a~a~a"
-			   line-break-str
-			   page-break-str
-			   space-tweaks))
-	     )
-
-	  (format out-port "~a\n~a\n" skip base)
-	  (dump-tweaks out-port (cdr tweak-list) (graceless-moment now))
-	)))
-
-  (define (dump-all-tweaks)
-    (let*
-     ((paper (ly:paper-book-paper (page-property  (car pages) 'paper-book)))
-      (parser (ly:output-def-parser paper))
-      (name  (format "~a-page-layout.ly"
-		     (ly:parser-output-name parser)))
-      (out-port (open-output-file name)))
-      
-     (ly:progress "Writing page layout to ~a" name)
-     (hash-for-each
-      (lambda (key val)
-	(format out-port "~a = {" key)
-	(dump-tweaks out-port (reverse val) (ly:make-moment 0 1))
-	 (display "}" out-port))
-       tweaks)
-     (close-port out-port)
-     ))
-
-  (define (handle-page page)
-    (define index 0)
-    (define music-system-heights
-      (map-in-order (lambda (sys)
-		      (* -1 (car (paper-system-extent sys Y))))
-		    (remove (lambda (sys)
-			      (ly:prob-property? sys 'is-title))
-			    (page-lines page))))
-    (define (handle-system sys)
-      (let*
-	  ((props `((line-break . #t)
-		    (spacing-parameters
-		     . ((system-Y-extent . ,(paper-system-extent sys Y))
-			(system-refpoint-Y-extent . ,(paper-system-staff-extents sys))
-			(system-index . ,index)
-			(music-system-heights . ,music-system-heights)
-			(page-system-count . ,(length (page-lines page)))
-			(page-printable-height . ,(page-printable-height page)) 
-			(page-space-left . ,(page-property page 'space-left))))
-		    )))
-
-	(if (equal? (car (page-lines page)) sys)
-	    (set! props (cons '(page-break . #t)
-			      props)))
-	(if (not (ly:prob-property? sys 'is-title))
-	    (record  (ly:spanner-bound (ly:prob-property sys 'system-grob) LEFT)
-		     props))
-
-	(set! index (1+ index))
-	))
-    (for-each handle-system (page-lines page)))
-
-  (for-each handle-page pages)
-  (dump-all-tweaks))
+(define-module (scm layout-page-layout)
+  #:use-module (srfi srfi-1)
+  #:use-module (oop goops describe)
+  #:use-module (oop goops)
+  #:use-module (scm paper-system)
+  #:use-module (scm page)
+  #:use-module (scm layout-page-dump)
+  #:use-module (lily)
+  #:export (post-process-pages optimal-page-breaks))
 
 (define (post-process-pages layout pages)
   (if (ly:output-def-lookup layout 'write-page-layout #f)
       (write-page-breaks pages)))
 
+;;;
+;;; Utilities for computing line distances and positions
+;;;
+(define (line-next-space line next-line layout)
+  "Return space to use between `line' and `next-line'.
+  `next-line' can be #f, meaning that `line' is the last line."
+  (let* ((title? (paper-system-title? line))
+         (next-title? (and next-line (paper-system-title? next-line))))
+    (cond ((and title? next-title?)
+           (ly:output-def-lookup layout 'between-title-space))
+          (title?
+           (ly:output-def-lookup layout 'after-title-space))
+          (next-title?
+           (ly:output-def-lookup layout 'before-title-space))
+          (else
+           (ly:prob-property
+            line 'next-space
+            (ly:output-def-lookup layout 'between-system-space))))))
+
+(define (line-next-padding line next-line layout)
+  "Return padding to use between `line' and `next-line'.
+  `next-line' can be #f, meaning that `line' is the last line."
+  (ly:prob-property
+   line 'next-padding
+   (ly:output-def-lookup layout 'between-system-padding)))
+
+
+(define (line-minimum-distance line next-line layout)
+  "Minimum distance between `line' reference position and `next-line'
+ reference position. If next-line is #f, return #f."
+  (and next-line
+       (max 0 (- (+ (interval-end (paper-system-extent next-line Y))
+                    (line-next-padding line next-line layout))
+                 (interval-start (paper-system-extent line Y))))))
+
+(define (line-ideal-distance line next-line layout)
+  "Ideal distance between `line' reference position and `next-line'
+ reference position. If next-line is #f, return #f."
+  (and next-line
+       (+ (max 0 (- (+ (interval-end (paper-system-staff-extents next-line))
+                       (line-next-padding line next-line layout))
+                    (interval-start (paper-system-staff-extents line))))
+          (line-next-space line next-line layout))))
+
+(define (first-line-position line layout)
+  "Position of the first line on page"
+  (max (+ (ly:output-def-lookup layout 'page-top-space)
+          (interval-end (paper-system-staff-extents line)))
+       (interval-end (paper-system-extent line Y))))
+
+(define (line-ideal-relative-position line prev-line layout)
+  "Return ideal position of `line', relative to `prev-line' position.
+  `prev-line' can be #f, meaning that `line' is the first line."
+  (if (not prev-line)
+      ;; first line on page
+      (first-line-position line layout)
+      ;; not the first line on page
+      (max (line-minimum-distance prev-line line layout)
+           (line-ideal-distance prev-line line layout))))
+
+(define (line-minimum-relative-position line prev-line layout)
+  "Return position of `line', relative to `prev-line' position.
+  `prev-line' can be #f, meaning that `line' is the first line."
+  (if (not prev-line)
+      ;; first line on page
+      (first-line-position line layout)
+      ;; not the first line on page
+      (line-minimum-distance prev-line line layout)))
+
+;;;
+;;; Page breaking functions
+;;;
+
 ;; Optimal distribution of
 ;; lines over pages; line breaks are a given.
 
@@ -152,309 +101,178 @@
 ;; - separate function for word-wrap style breaking?
 ;; - ragged-bottom? ragged-last-bottom?
 
-(define-public (optimal-page-breaks lines paper-book)
-  "Return pages as a list starting with 1st page. Each page is a 'page Prob."
-
-  (define MAXPENALTY 1e9)
-  (define paper (ly:paper-book-paper paper-book))
-
-  ;; ugh.
-  (define page-alist (layout->page-init (ly:paper-book-paper paper-book))) 
-  (define scopes (ly:paper-book-scopes paper-book))
-  (define force-equalization-factor #f)
-  (define (get-path node done)
-    
-    "Follow NODE.PREV, and return as an ascending list of pages. DONE
+(define (get-path node done)
+  "Follow NODE.PREV, and return as an ascending list of pages. DONE
 is what have collected so far, and has ascending page numbers."
-
-    (if (page? node)
-	(get-path (page-prev node) (cons node done))
-	done))
-
-  (define (combine-penalties force user best-paths)
-    (let* ((prev-force (if (null? best-paths)
-			   0.0
-			   (page-force (car best-paths))))
-	   (prev-penalty (if (null? best-paths)
-			     0.0
-			     (page-penalty (car best-paths))))
-	 (inter-system-space (ly:output-def-lookup paper 'between-system-space))
+  (if (page? node)
+      (get-path (page-prev node) (cons node done))
+      done))
+
+(define (combine-penalties force user best-paths
+                           inter-system-space force-equalization-factor)
+  (let* ((prev-force (if (null? best-paths)
+                         0.0
+                         (page-force (car best-paths))))
+         (prev-penalty (if (null? best-paths)
+                           0.0
+                           (page-penalty (car best-paths))))
 	 (relative-force (/ force inter-system-space))
 	 (abs-relative-force (abs relative-force)))
-
-      (+ (* abs-relative-force (+ abs-relative-force 1))
-	 prev-penalty
-	 (* force-equalization-factor (/ (abs (- prev-force force))
-					 inter-system-space))
-	 user)))
-
-  (define (space-systems page-height lines ragged?)
-    (let* ((global-inter-system-space
-	    (ly:output-def-lookup paper 'between-system-space))
-	   (top-space
-	    (ly:output-def-lookup paper 'page-top-space))
-	   (global-fixed-dist (ly:output-def-lookup paper 'between-system-padding))
-	   
-	   (system-vector (list->vector
-			   (append lines
-				   (if (= (length lines) 1)
-				       '(#f)
-				       '()))))
-	   (staff-extents
-	    (list->vector
-	     (append (map paper-system-staff-extents lines)
-		     (if (= (length lines) 1)
-			 '((0 . 0))
-			 '()))))
-
-	   (real-extents
-	    (list->vector
-	     (append
-	      (map
-	       (lambda (sys) (paper-system-extent sys Y)) lines)
-	      (if (= (length lines) 1)
-		  '((0 .  0))
-		  '()))))
-	   
-	   (system-count (vector-length real-extents))
-	   (topskip (max
-		     (+
-		      top-space
-		      (interval-end (vector-ref staff-extents 0)))
-		     (interval-end (vector-ref real-extents 0))
-		     ))
-	   (last-system (vector-ref system-vector (1- system-count)))
-	   (bottom-space (if (ly:prob? last-system)
-			     (ly:prob-property last-system 'bottom-space 0.0)
-			     0.0))
-	   (space-left (- page-height
-			  bottom-space
-			  (apply + (map interval-length
-					(vector->list real-extents)))))
-
-	   (space (- page-height
-		     topskip
-		     bottom-space
-		     (-  (interval-start
-			  (vector-ref real-extents (1- system-count))))))
-
-	   (calc-spring
-	    (lambda (idx)
-	      (let* (
-		     (upper-system (vector-ref system-vector idx))
-		     (between-space (ly:prob-property upper-system 'next-space
-							      global-inter-system-space))
-		     (fixed-dist (ly:prob-property upper-system 'next-padding
-							   global-fixed-dist))
-		     
-		     (this-system-ext (vector-ref staff-extents idx))
-		     (next-system-ext (vector-ref staff-extents (1+ idx)))
-		     (fixed (max 0 (- (+ (interval-end next-system-ext)
-					 fixed-dist)
-				      (interval-start this-system-ext))))
-		     (title1? (and (vector-ref system-vector idx)
-				   (paper-system-title? (vector-ref system-vector idx)
-							     )))
-		     (title2? (and
-			       (vector-ref system-vector (1+ idx))
-			       (paper-system-title? (vector-ref system-vector (1+ idx)))))
-		     (ideal (+
-			     (cond
-			      ((and title2? title1?)
-			       (ly:output-def-lookup paper 'between-title-space))
-			      (title1?
-			       (ly:output-def-lookup paper 'after-title-space))
-			      (title2?
-			       (ly:output-def-lookup paper 'before-title-space))
-			      (else between-space))
-			     fixed))
-		     (hooke (/ 1 (- ideal fixed))))
-		(list ideal hooke))))
-
-	   (springs (map calc-spring (iota (1- system-count))))
-	   (calc-rod
-	    (lambda (idx)
-	      (let* (
-		     (upper-system (vector-ref system-vector idx))
-		     (fixed-dist (ly:prob-property upper-system 'next-padding
-							   global-fixed-dist))
-		     (this-system-ext (vector-ref real-extents idx))
-		     (next-system-ext (vector-ref real-extents (1+ idx)))
-		     
-		     (distance (max  (- (+ (interval-end next-system-ext)
-					   fixed-dist)
-					(interval-start this-system-ext)
-					) 0))
-		     (entry (list idx (1+ idx) distance)))
-		entry)))
-	   (rods (map calc-rod (iota (1- system-count))))
-
-	   ;; we don't set ragged based on amount space left.
-	   ;; ragged-bottomlast = ##T is much more predictable
-	   (result (ly:solve-spring-rod-problem
-		    springs rods space
-		    ragged?))
-
-	   (force (car result))
-	   (positions
-	    (map (lambda (y)
-		   (+ y topskip))
-		 (cdr  result))))
-
-      (if #f ;; debug.
-	  (begin
-	    (display (list "\n# systems: " system-count
-			   "\nreal-ext" real-extents "\nstaff-ext" staff-extents
-			   "\ninterscore" global-inter-system-space
-			   "\nspace-left" space-left
-			   "\nspring,rod" springs rods
-			   "\ntopskip " topskip
-			   " space " space
-			   "\npage-height" page-height
-			   "\nragged" ragged?
-			   "\nforce" force
-			   "\nres" (cdr result)
-			   "\npositions" positions "\n"))))
-
-      (cons force positions)))
-
-  (define (walk-paths done-lines best-paths current-lines last? current-best)
-    "Return the best optimal-page-break-node that contains
+    (+ (* abs-relative-force (+ abs-relative-force 1))
+       prev-penalty
+       (* force-equalization-factor (/ (abs (- prev-force force))
+                                       inter-system-space))
+       user)))
+
+(define (space-systems page-height lines ragged? paper)
+  "Compute lines positions on page: return force and line positions as a pair.
+ force is #f if lines do not fit on page."
+  (let* ((springs (map (lambda (prev-line line)
+                         (list (line-ideal-distance prev-line line paper)
+                               (/ 1.0 (line-next-space prev-line line paper))))
+                       lines
+                       (cdr lines)))
+         (rods (map (let ((i -1))
+                      (lambda (prev-line line)
+                        (set! i (1+ i))
+                        (list i (1+ i)
+                              (line-minimum-distance prev-line line paper))))
+                       lines
+                       (cdr lines)))
+         (last-line (car (last-pair lines)))
+         (topskip (first-line-position (first lines) paper))
+         (space-to-fill (- page-height
+                           topskip
+                           (ly:prob-property last-line
+                                             'bottom-space 0.0)
+                           (- (interval-start (paper-system-extent
+                                               last-line Y)))))
+         (space-result
+          (ly:solve-spring-rod-problem springs rods space-to-fill ragged?)))
+    (cons (car space-result)
+          (map (lambda (y)
+                 (+ y topskip))
+               (cdr space-result)))))
+
+(define (walk-paths done-lines best-paths current-lines last? current-best
+                    paper-book page-alist)
+  "Return the best optimal-page-break-node that contains
 CURRENT-LINES.  DONE-LINES.reversed ++ CURRENT-LINES is a consecutive
 ascending range of lines, and BEST-PATHS contains the optimal breaks
 corresponding to DONE-LINES.
 
 CURRENT-BEST is the best result sofar, or #f."
+  (let* ((paper (ly:paper-book-paper paper-book))
+         (this-page (make-page
+                     page-alist
+                     'paper-book paper-book
+                     'is-last last?
+                     'page-number (if (null? best-paths)
+                                      (ly:output-def-lookup paper 'first-page-number)
+                                      (1+ (page-page-number (first best-paths))))))
+         (ragged-all? (eq? #t (ly:output-def-lookup paper 'ragged-bottom)))
+         (ragged-last? (eq? #t (ly:output-def-lookup paper 'ragged-last-bottom)))
+         (ragged? (or ragged-all? (and ragged-last? last?)))
+         (height (page-printable-height this-page))
+         (vertical-spacing (space-systems height current-lines ragged? paper))
+         (satisfied-constraints (car vertical-spacing))
+         (force (if satisfied-constraints
+                    (if (and last? ragged-last?)
+                        0.0
+                        satisfied-constraints)
+                    10000))
+         (positions (cdr vertical-spacing))
+         (get-break-penalty (lambda (sys)
+                              (ly:prob-property sys 'penalty 0.0)))
+         (user-nobreak-penalties (- (apply + (filter negative?
+                                                     (map get-break-penalty
+                                                          (cdr current-lines))))))
+         (user-penalty (+ (max (get-break-penalty (car current-lines)) 0.0)
+                          user-nobreak-penalties))
+         (total-penalty (combine-penalties
+                         force user-penalty best-paths
+                         (ly:output-def-lookup paper 'between-system-space)
+                         (ly:output-def-lookup paper 'verticalequalizationfactor 0.3)))
+         (new-best (if (or (not current-best)
+                           (and satisfied-constraints
+                                (< total-penalty (page-penalty current-best))))
+                       (begin
+                         (map (lambda (x)
+                                (page-set-property! this-page
+                                                    (car x)
+                                                    (cdr x)))
+                              (list (cons 'prev (if (null? best-paths)
+                                                    #f
+                                                    (car best-paths)))
+                                    (cons 'lines current-lines)
+                                    (cons 'force force)
+                                    (cons 'configuration positions)
+                                    (cons 'penalty total-penalty)))
+                         this-page)
+                       current-best)))
+    (if #f ;; debug
+        (display
+         (list
+          "\nuser pen " user-penalty
+          "\nsatisfied-constraints" satisfied-constraints
+          "\nlast? " last? "ragged?" ragged?
+          "\nis-better " is-better " total-penalty " total-penalty "\n"
+          "\nconfig " positions
+          "\nforce " force
+          "\nlines: " current-lines "\n")))
+    (if #f ; debug
+        (display (list "\nnew-best is " (page-lines new-best)
+                       "\ncontinuation of "
+                       (if (null? best-paths)
+                           "start"
+                           (page-lines (car best-paths))))))
+    (if (and (pair? done-lines)
+             ;; if this page is too full, adding another line won't help
+             satisfied-constraints)
+        (walk-paths (cdr done-lines) (cdr best-paths)
+                    (cons (car done-lines) current-lines)
+                    last? new-best
+                    paper-book page-alist)
+        new-best)))
 
-    (let* ((this-page-num (if (null? best-paths)
-                              (ly:output-def-lookup paper 'first-page-number)
-                              (1+ (page-page-number (car best-paths)))))
-
-	   (this-page (make-page
-		       page-alist
-		       'paper-book paper-book
-		       'is-last last?
-		       'page-number this-page-num))
-
-	   (ragged-all? (eq? #t (ly:output-def-lookup paper 'ragged-bottom)))
-	   (ragged-last? (eq? #t (ly:output-def-lookup paper 'ragged-last-bottom)))
-	   (ragged? (or ragged-all?
-			(and ragged-last?
-			     last?)))
-           (height (page-printable-height this-page))
-	   (vertical-spacing (space-systems height current-lines ragged?))
-	   
-	   (satisfied-constraints (car vertical-spacing))
-           (force (if satisfied-constraints
-		      (if (and last? ragged-last?)
-			  0.0
-			  satisfied-constraints)
-		      10000))
-	   (positions (cdr vertical-spacing))
-	   (get-break-penalty (lambda (sys)
-				(ly:prob-property sys 'penalty 0.0)))
-	   (user-nobreak-penalties
-	    (-
-	     (apply + (filter negative?
-			      (map get-break-penalty
-				   (cdr current-lines))))))
-           (user-penalty
-	    (+
-	     (max (get-break-penalty (car current-lines)) 0.0)
-	     user-nobreak-penalties))
-	   
-           (total-penalty (combine-penalties
-                           force user-penalty
-			   best-paths))
-
-           (is-better (or
-		       (not current-best)
-		       (and
-			satisfied-constraints
-			(< total-penalty (page-penalty current-best)))))
-           (new-best (if is-better
-			 (begin
-			   (map
-			    (lambda (x)
-			      (page-set-property! this-page
-						  (car x)
-						  (cdr x)))
-			    (list
-			     (cons 'prev (if (null? best-paths)
-					     #f
-					     (car best-paths)))
-			     (cons 'lines current-lines)
-			     (cons 'force force)
-			     (cons 'configuration positions)
-			     (cons 'penalty total-penalty)))
-			   this-page)
-                         current-best)))
-
-;;      (display total-penalty) (newline)
-      (if #f ;; debug
-          (display
-           (list
-            "\nuser pen " user-penalty
-	    "\nsatisfied-constraints" satisfied-constraints
-	    "\nlast? " last? "ragged?" ragged?
-            "\nis-better " is-better " total-penalty " total-penalty "\n"
-	    "\nconfig " positions
-            "\nforce " force
-	    "\nlines: " current-lines "\n")))
-
-      (if #f ; debug
-	  (display (list "\nnew-best is " (page-lines new-best)
-			 "\ncontinuation of "
-			 (if (null? best-paths)
-			     "start"
-			     (page-lines (car best-paths))))))
-
-      (if (and (pair? done-lines)
-               ;; if this page is too full, adding another line won't help
-               satisfied-constraints)
-          (walk-paths (cdr done-lines) (cdr best-paths)
-                      (cons (car done-lines) current-lines)
-                      last? new-best)
-	  new-best)))
-
-  (define (walk-lines done best-paths todo)
-    "Return the best page breaking as a single
+(define (walk-lines done best-paths todo paper-book page-alist)
+  "Return the best page breaking as a single
 page node for optimally breaking TODO ++
 DONE.reversed. BEST-PATHS is a list of break nodes corresponding to
 DONE."
-    
-    (if (null? todo)
-	(car best-paths)
-	(let* ((this-line (car todo))
-	       (last? (null? (cdr todo)))
-	       (next (walk-paths done best-paths (list this-line) last? #f)))
-
-	  ;; (display "\n***************")
-	  (walk-lines (cons this-line done)
-		      (cons next best-paths)
-		      (cdr todo)))))
-
-  (define (line-number node)
-    (ly:prob-property (car (page-lines node)) 'number))
-  
-  (ly:message (_ "Calculating page breaks..."))
-  (set! force-equalization-factor
-	(ly:output-def-lookup paper 'verticalequalizationfactor 0.3))
-  
-  (let* ((best-break-node (walk-lines '() '() lines))
-	 (break-nodes (get-path best-break-node '())))
-
-    (page-set-property! (car (last-pair break-nodes)) 'is-last #t)
-    (if #f; (ly:get-option 'verbose)
-	(begin
-	  (display (list
-		    "\nbreaks: " (map line-number break-nodes))
-		   "\nsystems " (map page-lines break-nodes)
-		   "\npenalties " (map page-penalty break-nodes)
-		   "\nconfigs " (map page-configuration break-nodes))))
-
-    ;; construct page stencils.
-    (for-each page-stencil break-nodes)
-    (post-process-pages paper break-nodes)
-    
-    break-nodes))
+  (if (null? todo)
+      (car best-paths)
+      (let* ((this-line (car todo))
+             (last? (null? (cdr todo)))
+             (next (walk-paths done best-paths (list this-line) last? #f
+                               paper-book page-alist)))
+        (walk-lines (cons this-line done)
+                    (cons next best-paths)
+                    (cdr todo)
+                    paper-book
+                    page-alist))))
+
+(define-public (optimal-page-breaks lines paper-book)
+  "Return pages as a list starting with 1st page. Each page is a 'page Prob."
+  (let* ((paper (ly:paper-book-paper paper-book))
+         (page-alist (layout->page-init paper)) 
+         (force-equalization-factor (ly:output-def-lookup
+                                     paper 'verticalequalizationfactor 0.3)))
+    (ly:message (_ "Calculating page breaks..."))
+    (let* ((best-break-node (walk-lines '() '() lines paper-book page-alist))
+           (break-nodes (get-path best-break-node '())))
+      (page-set-property! (car (last-pair break-nodes)) 'is-last #t)
+      (if #f; (ly:get-option 'verbose)
+          (begin
+            (display (list
+                      "\nbreaks: " (map (lambda (node)
+                                          (ly:prob-property (car (page-lines node))
+                                                            'number))
+                                        break-nodes)
+                      "\nsystems " (map page-lines break-nodes)
+                      "\npenalties " (map page-penalty break-nodes)
+                      "\nconfigs " (map page-configuration break-nodes)))))
+      ;; construct page stencils.
+      (for-each page-stencil break-nodes)
+      (post-process-pages paper break-nodes)
+      break-nodes)))
Index: scm/lily.scm
===================================================================
RCS file: /cvsroot/lilypond/lilypond/scm/lily.scm,v
retrieving revision 1.399
diff -u -r1.399 lily.scm
--- scm/lily.scm	27 May 2006 01:13:06 -0000	1.399
+++ scm/lily.scm	14 Jul 2006 18:44:36 -0000
@@ -263,7 +263,6 @@
 	    "define-grobs.scm"
 	    "define-grob-interfaces.scm"
 	    "define-stencil-commands.scm"
-	    "layout-page-layout.scm"
 	    "titling.scm"
 	    
 	    "paper.scm"