#:use-module (lily)
#:export (post-process-pages optimal-page-breaks make-page-from-systems
page-breaking-wrapper
+ stretchable-line? ; delete me
;; utilities for writing custom page breaking functions
line-height line-next-space line-next-padding
line-minimum-distance line-ideal-distance
first-line-position
line-ideal-relative-position line-minimum-relative-position
- line-minimum-position-on-page stretchable-line?
+ line-minimum-position-on-page
page-maximum-space-to-fill page-maximum-space-left space-systems))
+; this is for 2-pass spacing. Delete me.
+(define (stretchable-line? line)
+ "Say whether a system can be stretched."
+ (not (or (ly:prob-property? line 'is-title)
+ (let ((system-extent (paper-system-staff-extents line)))
+ (= (interval-start system-extent)
+ (interval-end system-extent))))))
+
+(define (stretch-and-draw-page paper-book systems page-number ragged last)
+ (define (stretchable? sys)
+ (and (ly:grob? sys)
+ (ly:grob-property sys 'stretchable)))
+
+ (define (height-estimate sys)
+ (interval-length
+ (if (ly:grob? sys)
+ (ly:grob-property sys 'pure-Y-extent)
+ (paper-system-extent sys Y))))
+
+ (define (max-stretch sys)
+ (if (stretchable? sys)
+ (ly:grob-property sys 'max-stretch)
+ 0.0))
+
+ (define (print-system sys)
+ (if (ly:grob? sys)
+ (ly:system-print sys)
+ sys))
+
+ (define (set-line-stretch! sorted-lines rest-height space-left)
+ (if (not (null? sorted-lines))
+ (let* ((line (first sorted-lines))
+ (height (height-estimate line))
+ (stretch (min (max-stretch line)
+ (if (positive? rest-height)
+ (/ (* height space-left) rest-height)
+ 0.0))))
+ (if (stretchable? line)
+ (ly:system-stretch line stretch))
+ (set-line-stretch! (cdr sorted-lines)
+ (if (stretchable? line)
+ (- rest-height height)
+ rest-height)
+ (- space-left stretch)))))
+
+ (let* ((page (make-page paper-book
+ 'page-number page-number
+ 'is-last last))
+ (paper (ly:paper-book-paper paper-book))
+ (height (page-printable-height page))
+ ; there is a certain amount of impreciseness going on here:
+ ; the system heights are estimated, we aren't using skyline distances
+ ; yet, etc. If we overstretch because of underestimation, the result
+ ; is very bad. So we stick in some extra space, just to be sure.
+ (buffer (/ height 10.0))
+ (total-system-height (apply + (map height-estimate systems)))
+ (height-left (- height total-system-height buffer)))
+
+ (if (not ragged)
+ (set-line-stretch! (sort systems
+ (lambda (s1 s2)
+ (< (height-estimate s1)
+ (height-estimate s2))))
+ (apply + (map height-estimate
+ (filter stretchable? systems)))
+ (- (page-printable-height page)
+ total-system-height)))
+
+ (let* ((lines (map print-system systems))
+ (posns (if (null? lines)
+ (list)
+ (let* ((paper (ly:paper-book-paper paper-book))
+ (space-to-fill (page-maximum-space-to-fill
+ page lines paper))
+ (spacing (space-systems space-to-fill lines ragged paper #f)))
+ (if (and (> (length lines) 1)
+ (or (not (car spacing)) (inf? (car spacing))))
+ (begin
+ (ly:warning (_ "Can't fit systems on page -- ignoring between-system-padding"))
+ (cdr (space-systems space-to-fill lines ragged paper #t)))
+ (cdr spacing))))))
+ (page-set-property! page 'lines lines)
+ (page-set-property! page 'configuration posns)
+ page)))
+
(define (page-breaking-wrapper paper-book)
"Compute line and page breaks by calling the page-breaking paper variable,
then performs the post process function using the page-post-process paper
;;;
;;; Utilities for computing line distances and positions
;;;
+(define (line-extent line)
+ "Return the extent of the line (its lowest and highest Y-coordinates)."
+ (paper-system-extent line Y))
+
(define (line-height line)
"Return the system height, that is the length of its vertical extent."
- (interval-length (paper-system-extent line Y)))
+ (interval-length (line-extent line)))
(define (line-next-space line next-line layout)
"Return space to use between `line' and `next-line'.
"Minimum distance between `line' reference position and `next-line'
reference position. If next-line is #f, return #f."
(and next-line
- (let ((non-skyline-distance (- (interval-end (paper-system-extent next-line Y))
- (interval-start (paper-system-extent line Y)))))
- (max 0 (+ (ly:prob-property next-line 'skyline-distance non-skyline-distance)
- (if ignore-padding 0 (line-next-padding line next-line layout)))))))
+ (let ((padding (if ignore-padding
+ 0
+ (line-next-padding line next-line layout))))
+ (if (or (ly:grob? line) (ly:grob? next-line))
+ (max 0 (+ padding
+ (- (interval-start (line-extent line))
+ (interval-end (line-extent next-line)))))
+ (max 0 (+ padding
+ (ly:paper-system-minimum-distance line next-line)))))))
(define (line-ideal-distance line next-line layout ignore-padding)
"Ideal distance between `line' reference position and `next-line'
0.0
(ly:output-def-lookup layout 'page-top-space))
(interval-end (paper-system-staff-extents line)))
- (interval-end (paper-system-extent line Y))))
+ (interval-end (line-extent line))))
(define (line-ideal-relative-position line prev-line layout ignore-padding)
"Return ideal position of `line', relative to `prev-line' position.
(position (+ (line-minimum-relative-position line prev-line layout #f)
(if prev-line prev-position 0.0)))
(bottom-position (- position
- (interval-start (paper-system-extent line Y)))))
+ (interval-start (line-extent line)))))
(and (or (not prev-line)
(< bottom-position (page-printable-height page)))
position)))
-(define (stretchable-line? line)
- "Say whether a system can be stretched."
- (not (or (ly:prob-property? line 'is-title)
- (let ((system-extent (paper-system-staff-extents line)))
- (= (interval-start system-extent)
- (interval-end system-extent))))))
-
(define (page-maximum-space-to-fill page lines paper)
"Return the space between the first line top position and the last line
bottom position. This constitutes the maximum space to fill on `page'
(first-line-position (first lines) paper)
(ly:prob-property last-line
'bottom-space 0.0)
- (- (interval-start (paper-system-extent last-line Y))))))
+ (- (interval-start (line-extent last-line))))))
(define (page-maximum-space-left page)
(let ((paper (ly:paper-book-paper (page-property page 'paper-book))))
(and position
(- (page-printable-height page)
(- position
- (interval-start (paper-system-extent line Y)))))
+ (interval-start (line-extent line)))))
(bottom-position (cdr lines) line position)))))))
;;;
(+ y topskip)))
(cdr space-result)))))
-(define (make-page-from-systems paper-book lines page-number ragged last)
- "Return a new page, filled with `lines'."
- (let* ((page (make-page paper-book
- 'lines lines
- 'page-number page-number
- 'is-last last))
- (posns (if (null? lines)
- (list)
- (let* ((paper (ly:paper-book-paper paper-book))
- (space-to-fill (page-maximum-space-to-fill
- page lines paper))
- (spacing (space-systems space-to-fill lines ragged paper #f)))
- (if (or (not (car spacing)) (inf? (car spacing)))
- (begin
- (ly:warning (_ "Can't fit systems on page -- ignoring between-system-padding"))
- (cdr (space-systems space-to-fill lines ragged paper #t)))
- (cdr spacing))))))
- (page-set-property! page 'configuration posns)
- page))
;;;
;;; Page breaking function
projects / lilypond.git / blobdiff