2 ; should include default value?
4 ;;; ::::::: should generate documentation for score elements from here.
6 (define (property-description symbol type? description)
7 (list symbol type? description))
9 (define (lily-interface symbol description props)
17 (define (uniqued-alist alist acc)
19 (if (assoc (caar alist) acc)
20 (uniqued-alist (cdr alist) acc)
21 (uniqued-alist (cdr alist) (cons (car alist) acc)
24 (define (element-description name . interfaces)
25 (let* ((ifs (cons general-element-interface interfaces))
26 (props (map caddr ifs))
27 (prop-typep-pairs (map (lambda (x) (cons (car x) (cadr x)))
28 (apply append props)))
31 (list (cons 'separator "\n\n\n") ;easy printing.
33 (cons 'interfaces syms)
34 (cons 'interface-descriptions ifs)
35 ; (cons 'interface-descriptions (cadr merged))
36 ;; description of the element itself?
37 (cons 'properties prop-typep-pairs)
41 (define general-element-interface
43 'general-element-interface
44 "All elements support this"
46 (property-description 'X-offset-callbacks list? "list of functions, each taking an element and axis argument. The function determine the position relative to this element's parent. The last one in the list is called first")
47 (property-description 'Y-offset-callbacks list? "see <code> X-offset-callbacks</code>")
48 (property-description 'X-extent-callback procedure? "procedure taking an element and axis argument, returning a number-pair. The return value is the extent of the element.")
49 (property-description 'Y-extent-callback procedure? "see <code> X-extent-callback </code>")
50 (property-description 'font-relative-size integer? "")
51 (property-description 'extra-offset number-pair? "pair of reals (a cons) forcing an extra offset before outputting")
52 (property-description 'interfaces list? "list of symbols indicating the interfaces supported by this object. Is initialized from the <code>meta</code> field.")
53 (property-description 'dependencies list? "list of score-element pointers that indicate who to compute first for certain global passes")
54 (property-description 'no-spacing-rods boolean? "read from elements: boolean that makes Separation_item ignore this item (MOVE ME TO ITEM)")
55 (property-description 'extra-extent-X number-pair? "enlarge in X dimension by this much, measured in staff space")
56 (property-description 'extra-extent-Y number-pair? "see <code>extra-extent-Y</code>")
57 (property-description 'minimum-extent-X number-pair? "minimum size in X dimension, measured in staff space")
58 (property-description 'minimum-extent-Y number-pair? "see <code>minimum-extent-Y</code>")
59 (property-description 'origin ly-input-location? "location in input file of the definition")
60 (property-description 'transparent boolean? "This is almost the
61 same as setting molecule-callback to #f, but this retains the
62 dimensions of this element, which means that you can erase elements
64 (property-description 'molecule-callback procedure? "Function taking graphical element as argument, returning a Scheme encoded Molecule
66 This function can be called more than once (for instance once for
67 computing dimensions, and once for computing the output). Therefore,
68 this function should have no side-effects on its argument.
69 Caching of computed values is permissible, and generally useful, though.
75 (define beam-interface
80 (property-description 'y-position number? "position of left edge")
81 (property-description 'height number? "dy")
82 (property-description 'flag-width-function procedure? "")
83 (property-description 'damping integer? "amount of beam slope damping should beam slope be damped? 0: no, 1: yes, 100000: horizontal beams ")
84 (property-description 'default-neutral-direction dir? "which
85 direction to choose if we're in the middle of the staff ")
86 (property-description 'thickness number? "weight of beams, in staffspace")
87 (property-description 'space-function procedure? "function of type multiplicity -> real (in staffspace)")
88 (property-description 'beamed-stem-shorten number? "")
89 (property-description 'height-quants number? "")
90 (property-description 'vertical-position-quant-function procedure? "")
91 (property-description 'dir-function procedure? "")
92 (property-description 'damping number? "damping factor.")
93 (property-description 'outer-stem-length-limit number? "catch
94 suspect beam slopes, set slope to zero if outer stem is lengthened
95 more than this (in staffspace)")
96 (property-description 'slope-limit number? "set slope to zero if slope is running away steeper than this.")
104 (define clef-interface
109 (property-description 'non-default boolean? "not set because of existence of a bar?")
110 (property-description 'change boolean? "is this a change clef (smaller size)?")
111 (property-description 'glyph string? "a string determining what glyph is typeset")
115 (define axis-group-interface
117 'axis-group-interface
118 "a group of coupled elements"
120 (property-description 'axes list? "list of axis (number) in which this group works")
123 (define note-column-interface
125 'note-column-interface
126 "Stem and noteheads combined"
128 (property-description 'horizontal-shift integer? "integer that identifies ranking of note-column for horizontal shifting.")
129 (property-description 'force-hshift number? "amount of collision_note_width that overides automatic collision settings.")
130 (property-description 'merge-differently-dotted boolean? "merge black noteheads with differing dot count in collisions.")
134 (define stem-interface
139 (property-description 'thickness number? "thickness, measured in stafflinethickness")
140 (property-description 'beamed-lengths list? "list of stem lengths given beam multiplicity ")
141 (property-description 'beamed-minimum-lengths list? "list of minimum stem lengths given beam multiplicity")
142 (property-description 'stem-centered boolean? "Center stems on note heads. Useful for mensural notation")
143 (property-description 'lengths list? "Stem length given multiplicity of flag")
144 (property-description 'beam ly-element? "pointer to the beam, if applicable")
145 (property-description 'stem-shorten list? "shorten stems in forced directions given flag multiplicity")
146 (property-description 'duration-log integer? "log of the duration, ie. 0=whole note, 1 = half note, etc.")
147 (property-description 'beaming number-pair? "number of beams extending to left and right")
148 (property-description 'default-neutral-direction dir? "Where to go if we're in the middle of the staff")
149 (property-description 'stem-end-position number? "Where does the stem end (the end is opposite to the support-head")
150 (property-description 'support-head ly-element? "the note head at
151 one end of the stem")
152 (property-description 'heads list? "list of note heads")
153 (property-description 'direction dir? "up or down")
154 (property-description 'stem-length number? "length of stem")
155 (property-description 'style string? "") ; symbol!?
156 (property-description 'flag-style string? "") ; symbol!?
157 (property-description 'dir-forced boolean? "set if direction has been forced; read by Beam.")
161 (define slur-interface
166 (property-description 'de-uglify-parameters list? "list of 3 real constants. They define the valid areas for the middle control points. Used in de_uglyfy. They are a bit empirical.")
167 (property-description 'details list? "alist containing contaning a few magic constants.")
168 (property-description 'attachment pair? "cons of symbols, '(LEFT-TYPE . RIGHT-TYPE), where both types may be alongside-stem, stem, head or loose-end")
169 (property-description 'direction dir? "up or down?")
170 (property-description 'attachment-offset pair? "cons of offsets, '(LEFT-offset . RIGHT-offset). This offset is added to the attachments to prevent ugly slurs.")
171 (property-description 'beautiful number? "number that dictates when a slur should be de-uglyfied. It correlates with the enclosed area between noteheads and slurs. A value of 0.1 yields only undisturbed slurs, a value of 5 will tolerate quite high blown slurs.")
172 (property-description 'y-free number? "minimal vertical gap between slur and noteheads or stems")
173 (property-description 'control-points list? "[internal] control points of bezier curve")
174 (property-description 'extremity-rules list? "an alist (procedure slur dir) -> attachment to determine the attachment (see above). If procedure returns #t, attachment is used. Otherwise, the next procedure is tried.")
175 (property-description 'extremity-offset-alist list? "an alist (attachment stem-dir*dir slur-dir*dir) -> offset. The offset adds to the centre of the notehead, or stem.")
176 (property-description 'thickness list? "The thickness[stafflinethickness] of slur in the centre.")
177 (property-description 'dashed number? "[FIXME: use dash-period/dash length; see text-spanner] number representing the length of the dashes.")
183 (define side-position-interface
185 'side-position-interface
186 "Position a victim object (this one) next to other objects (the support)."
188 (property-description 'side-support list? "the support, a list of score elements")
189 (property-description 'direction-source ly-element? "in case side-relative-direction is set, which element to get the direction from ")
190 (property-description 'direction dir? "where to put the victim object (left or right?)")
191 (property-description 'side-relative-direction dir? "if set: get the direction from a different object, and multiply by this.")
192 (property-description 'minimum-space number? "minimum distance that the victim should move (after padding)")
193 (property-description 'padding number? "add this much extra space between victim and support")
194 (property-description 'self-alignment-X number? "real number: -1 =
195 left aligned, 0 = center, 1 right-aligned in X direction. <p> Set to
196 an element pointer, if you want that element to be the center. In
197 this case, the center element should have this object as a reference
200 (property-description 'self-alignment-Y number? "like self-alignment-X but for Y axis")
205 (define accidentals-interface
207 'accidentals-interface
210 (property-description 'left-padding number? "space left of accs")
211 (property-description 'right-padding number? "space right of accs")
215 (define line-of-score-interface
217 'line-of-score-interface
218 "Super element, parent of all:
220 The columns of a score that form one line. The toplevel element.
221 Any element has a Line_of_score as both X and Y reference
222 point. The Paper_score contains one element of this type. Control
223 enters the Score_element dependency calculation from this single
224 Line_of_score object."
226 (property-description 'between-system-string string? "string
227 to dump between two systems. Useful for forcing pagebreaks")
228 (property-description 'spacing-procedure procedure? "procedure taking
229 graphical element as argument. This is called after before-line-breaking-callback, but before the actual line breaking itself. Return value is ignored")
230 (property-description 'before-line-breaking-callback procedure?
231 "Procedure taking graphical element as argument.
232 This procedure is called (using dependency resolution) before line breaking, but after generating discretionary items. Return value is ignored")
233 (property-description 'after-line-breaking-callback procedure?
234 "Procedure taking graphical element as argument.
235 This procedure is called (using dependency resolution) after line breaking. Return value is ignored")
236 (property-description 'all-elements list? "list of all score elements in this line. Needed for protecting elements from GC.")
237 (property-description 'columns list? "list of all paper columns")
240 (define note-head-interface
245 (property-description 'style symbol? "symbol that sets note head style")
249 (define note-name-interface
254 (property-description 'style symbol? "symbol that sets note name style")
259 (define rhythmic-head-interface
261 'rhythmic-head-interface
264 (property-description 'dot ly-element? "reference to Dots object.")
265 (property-description 'stem ly-element? "pointer to Stem object")
266 (property-description 'duration-log integer? "2-log of the notehead duration")
269 (define rest-interface
274 (property-description 'style string? "string specifying glyph style"))))
276 (define tuplet-bracket-interface
278 'tuplet-bracket-interface
279 "A bracket with a number in the middle, used for tuplets."
281 (property-description 'beams list? "list of beam ptrs.")
282 (property-description 'columns list? " list of note-columns.")
283 (property-description 'number-gap number? "")
284 (property-description 'delta-y number? "amount of ascension")
285 (property-description 'thick number? "thickness, in stafflinethickness")
290 (define align-interface
293 " Order elements top to bottom/left to right/right to left etc."
295 (property-description 'stacking-dir dir? "stack contents of elements in which direction ?")
296 (property-description 'align-dir dir? "Which side to align? -1: left side, 0: around center of width, 1: right side")
297 (property-description 'threshold number-pair? "(cons MIN MAX), where MIN and MAX are dimensions in staffspace")
298 (property-description 'alignment-done boolean? "boolean to administrate whether we've done the alignment already (to ensure that the process is done only once)")
299 (property-description 'center-element ly-element? "element which will be at the
300 center of the group after aligning (when using
301 Align_interface::center_on_element). ")
302 (property-description 'elements list? "to be aligned elements ")
303 (property-description 'axes list? "list of axis numbers. Should contain only one number.")
306 (define aligned-interface
309 "read by align-interface"
311 (property-description 'minimum-space number-pair? "(cons LEFT RIGHT)")
312 (property-description 'extra-space number-pair? "(cons LEFT RIGHT)")
315 (define break-aligned-interface
317 'break-aligned-interface
318 "Items that are aligned in prefatory matter"
320 (property-description 'break-align-symbol symbol? "the index in the spacing table (symbol) of the to be aligned item.")
321 (property-description 'visibility-lambda procedure? "a function that takes the break direction and returns a cons of booleans containing (TRANSPARENT . EMPTY)")
322 (property-description 'breakable boolean? "boolean indicating if this is a breakable item (clef, barline, key sig, etc.)")
325 (define chord-name-interface
327 'chord-name-interface
328 "generate a chord name"
330 (property-description 'pitches list? "list of musical-pitch")
331 (property-description 'inversion list? " musical-pitch, optional")
332 (property-description 'bass list? " musical-pitch, optional")
335 (define time-signature-interface
337 'time-signature-interface
338 "A time signature, in different styles"
340 (property-description 'fraction number-pair? "")
341 (property-description 'style string? "")
344 (define bar-line-interface
349 (property-description 'barsize-procedure procedure? "how to compute the size of a bar line")
350 (property-description 'kern number? "space after a thick line")
351 (property-description 'thin-kern number? "space after a hair-line")
352 (property-description 'hair-thickness number? "thickness, measured in stafflinethickness")
353 (property-description 'thick-thickness number? "thickness, measured in stafflinethickness")
354 (property-description 'glyph string? "what kind barline? A concatenation of |, : and .")
355 (property-description 'bar-size number? "")
356 (property-description 'break-glyph-function procedure? "function taking glyph and break-direction, returning the glyph at a line break")
362 (define hairpin-interface
367 (property-description 'grow-direction dir? "crescendo or decrescendo?")
368 (property-description 'thickness number? "thickness, measured in stafflinethickness")
369 (property-description 'height number? "height, measured in staffspace in ")
372 (define arpeggio-interface
377 (property-description 'stems list? "list of stem objects, corresponding to the notes that the arpeggio has to be before.")
382 (define note-collision-interface
384 'note-collision-interface
387 (property-description 'note-width 'number? "unit for horizontal translation, measured in staff-space.")
391 (define custos-interface
394 "A custos is a staff context symbol that appears at the end of a
395 staff line with monophonic musical contents (i.e. with a single
396 voice). It anticipates the pitch of the first note of the following
397 line and thus helps the player or singer to manage line breaks
398 during performance, thus enhancing readability of a score.
400 Custodes were frequently used in music notation until the 16th
401 century. There were different appearences for different notation
402 styles. Nowadays, they have survived only in special forms of
403 musical notation such as via the editio vaticana dating back to the
404 beginning of the 20th century.
406 [TODO: add to glossary]"
409 (property-description 'style string? "a string determining what glyph is
410 typeset. Current choices are mensural,
411 hufnagel, vaticana and medicaea [TODO: should use symbol] ")
417 (define dot-interface
420 "The dots to go with a notehead/rest. A separate interface, since they
421 are a party in collision resolution."
423 (property-description 'direction dir? "Direction to handle staff-line collisions in.")
424 (property-description 'dot-count integer? "number of dots")
427 (define font-interface
430 "Any symbol that is typeset through fixed sets of glyphs (ie. fonts)"
432 (property-description 'font-style symbol? "a precooked set of font definitions, eg. finger volta timesig mark script large Large dynamic")
433 (property-description 'font-series symbol? "partial font definition: medium, bold")
434 (property-description 'font-shape symbol? "partial font definition: upright or italic")
435 (property-description 'font-family symbol? "partial font definition: music roman braces dynamic math ...")
436 (property-description 'font-name symbol? "partial font definition: base name of font file FIXME: should override other partials")
437 (property-description 'font-point-size number? "partial font definition: exact font size in points FIXME: should override font-relative-size")
438 (property-description 'font-relative-size number? "partial font definition: the relative size, 0 is style-sheet's normal size, -1 is smaller, +1 is bigger")
442 (define text-interface
445 "A scheme markup text"
447 (property-description 'text (lambda (x) (or (string? x) (list? x))) "
448 Scheme markup text. It is defined as follows:
451 TEXT : STRING | (MARKUP SENTENCE)<br>
452 MARKUP: PROPERTY | ABBREV<br>
453 SENTENCE: TEXT | SENTENCE TEXT<br>
454 PROPERTY: (key . value)<br>
455 ABBREV: rows lines roman music bold italic named super sub text, or any font-style
458 So, TEXT is either a string, or a list of which the CAR is a MARKUP.
459 MARKUP is either a CONS: an element property '(key . value) or a symbol:
460 a predefined abbreviation for a list of element properties.
463 The following abbreviations are currently defined:
465 <dt>rows<dd> horizontal mode: set all text on one line (default)
466 <dt>lines<dd> vertical mode: set every text on new line
467 <dt>roman<dd> select roman font
468 <dt>music<dd> select feta font
469 <dt>bold<dd> select bold series
470 <dt>italic<dd> select italic shape
471 <dt>named<dd> lookup by character name
472 <dt>text<dd> plain text lookup (by character value)
473 <dt>super<dd> superscript
474 <dt>sub<dd> subscript
475 <dt> any font-style<dd> finger volta timesig mmrest mark script large Large dynamic
478 ;; Should move this somewhere else?
479 (property-description 'align number? "the alignment of the text, 0 is horizontal, 1 is vertical")
480 (property-description 'lookup symbol? "lookup method: 'value for plain text, 'name for character-name")
481 (property-description 'raise number? "height for text to be raised (a negative value lowers the text")
482 (property-description 'kern number? "amount of extra white space to add before text. This is `relative'(?) to the current alignment.")
483 (property-description 'magnify number? "the magnification factor. FIXME: doesn't work for feta fonts")
486 (define dot-column-interface
488 'dot-column-interface
489 "Interface that groups dots so they form a column"
493 (define dynamic-interface
496 "Any kind of loudness sign"
501 (define finger-interface
504 "A fingering instruction"
508 (define separation-spanner-interface
510 'separation-spanner-interface
511 "Spanner that containing <code>separation-item-interface</code> elements to calculate rods"
514 (define text-script-interface
516 'text-script-interface
521 (define grace-alignment-interface
523 'grace-alignment-interface
524 "put grace notes in line"
526 (property-description 'horizontal-space number? "amount of space to add after a note (in staff-space)")
530 (define hara-kiri-group-interface
532 'hara-kiri-group-interface
533 " As Vertical_group_spanner, but keep track of interesting items. If
534 we don't contain any interesting items after linebreaking, then
535 gracefully commit suicide. Objective: don't disgrace Lily by
536 typesetting empty lines in orchestral scores."
538 (property-description 'items-worth-living list? "list of interesting items. If empty in a particular system, clear that system.")
543 (define lyric-hyphen-interface
545 'lyric-hyphen-interface
546 "A centred hyphen is a simple line between lyrics used to divide
547 syllables. The length of the hyphen line should stretch based on the
548 size of the gap between syllables."
551 (property-description 'thickness number? "thickness of line (in stafflinethickness)")
552 (property-description 'height number? "vertical offset (in staffspace)")
554 (property-description 'minimum-length number? "try to make the hyphens at least this long. Also works as a scaling parameter for the length")
555 (property-description 'word-space number? "elongate left by this much (FIXME: cumbersome semantics)")
558 (define key-signature-interface
560 'key-signature-interface
561 "A group of accidentals."
563 (property-description 'c0-position integer? "integer indicating the position of central C")
564 (property-description 'old-accidentals list? "list of (pitch, accidental) pairs")
565 (property-description 'new-accidentals list? "list of (pitch, accidental) pairs")
568 (define lyric-extender-interface
570 'lyric-extender-interface
571 "The extender is a simple line at the baseline of the lyric
572 that helps show the length of a melissima (tied/slurred note)."
574 (property-description 'word-space number? "")
575 (property-description 'height number? "in stafflinethickness")
576 (property-description 'right-trim-amount number? "")
580 (define lyric-syllable-interface
582 'lyric-syllable-interface
583 "a single piece of lyrics"
585 (property-description 'word-space number? "")
589 (define mark-interface
596 (define multi-measure-rest-interface
598 'multi-measure-rest-interface
599 "A rest that spans a whole number of measures."
602 (property-description 'columns list? "list of paper-columns")
603 (property-description 'expand-limit integer? "maximum number of measures expanded in church rests")
604 (property-description 'minimum-width number? "minimum-width of rest symbol, in staffspace")
605 (property-description 'padding number? "padding between number and rest. Measured in staffspace.")
608 (define paper-column-interface
610 'paper-column-interface
613 (property-description 'column-space-strength number? "relative strength of space following breakable columns (eg. prefatory matter)")
614 (property-description 'before-musical-spacing-factor number?
615 "space before musical columns (eg. taken by accidentals) get this much
616 stretched when they follow a musical column, in absence of grace
617 notes. 0.0 means no extra space (accidentals are ignored)")
618 (property-description 'stem-spacing-correction number? "optical correction amount.")
619 (property-description 'before-grace-spacing-factor number? " stretch space this much if there are grace notes before the column")
620 (property-description 'when moment? "when does this column happen?")
621 (property-description 'bounded-by-me list? "list of spanners that have this
622 column as start/begin point. Only columns that have elements or act as bounds are spaced.")
623 (property-description 'dir-list list? "list of stem directions")
624 (property-description 'shortest-playing-duration moment? "duration of the shortest playing in that column.")
625 (property-description 'shortest-starter-duration moment? "duration of the shortest notes that starts exactly in this column.")
626 (property-description 'contains-grace boolean? "Used to widen entries for grace notes.")
627 (property-description 'extra-space number-pair? "pair of distances")
628 (property-description 'stretch-distance number-pair? "pair of distances")
631 (define spaceable-element-interface
633 'spaceable-element-interface
634 "An element (generally a Paper_column) that takes part in the
637 (property-description 'minimum-distances list? "list of rods (ie. (OBJ . DIST) pairs)")
638 (property-description 'ideal-distances list? "(OBJ . (DIST . STRENGTH)) pairs")
639 (property-description 'dir-list list? "list of stem directions, needed for optical spacing correction.")
642 (define rest-collision-interface
644 'rest-collision-interface
645 "Move around ordinary rests (not multi-measure-rests) to avoid
648 (property-description 'maximum-rest-count integer? "kill off rests so we don't more than this number left.")
649 (property-description 'minimum-distance number? "minimum distance between notes and rests.")
650 (property-description 'elements list? "list of elements (NoteColumn,
651 generally) participating in the collision. The
652 <code>rest-collision</code> property in <code>elements</code> is set
653 to a pointer to the collision")
656 (define script-interface
661 (property-description 'script-priority number? "A sorting key that determines in what order a script is within a stack of scripts")
664 (define script-column-interface
666 'script-column-interface
667 "An interface that sorts scripts according to their <code>script-priority</code>"
671 (define spacing-spanner-interface
673 'spacing-spanner-interface
676 (property-description 'maximum-duration-for-spacing moment? "space as if a duration of this type is available in this measure.")
677 (property-description 'arithmetic-basicspace number? "The space taken by a note is determined by the formula
679 SPACE = arithmetic_multiplier * ( C + log2 (TIME) ))
681 where TIME is the amount of time a note occupies. The value of C is
682 chosen such that the smallest space within a measure is
683 arithmetic_basicspace:
685 C = arithmetic_basicspace - log2 (mininum (SHORTEST, 1/8))
687 The smallest space is the one following the shortest note in the
688 measure, or the space following a hypothetical 1/8 note. Typically
689 arithmetic_basicspace is set to a value so that the shortest note
690 takes about two noteheads of space (ie, is followed by a notehead of
693 2*quartwidth = arithmetic_multiplier * ( C + log2 (SHORTEST) ))
695 { using: C = arithmetic_basicspace - log2 (mininum (SHORTEST, 1/8)) }
696 { assuming: SHORTEST <= 1/8 }
698 = arithmetic_multiplier *
699 ( arithmetic_basicspace - log2 (SHORTEST) + log2 (SHORTEST) )
701 = arithmetic_multiplier * arithmetic_basicspace
703 { choose: arithmetic_multiplier = 1.0*quartwidth (why?)}
705 = quartwidth * arithmetic_basicspace
709 arithmetic_basicspace = 2/1 = 2
711 If you want to space your music wider, use something like:
713 arithmetic_basicspace = 4.;
716 (property-description 'arithmetic-multiplier number? "see arithmetic-basicspace")
720 (define staff-symbol-interface
722 'staff-symbol-interface
723 "This spanner draws the lines of a staff. The middle line is
726 (property-description 'staff-space number? "Amount of line leading relative to global staffspace")
727 (property-description 'line-count integer? "Number of staff lines")
730 (define stem-tremolo-interface
732 'stem-tremolo-interface
735 (property-description 'stem ly-element? "pointer to the stem object.")
736 (property-description 'beam-width number? "width of the tremolo sign")
737 (property-description 'beam-thickness number? "thickness, measured in staffspace")
738 (property-description 'beam-space-function procedure? "function returning space given multiplicity")
741 (define separation-item-interface
743 'separation-item-interface
744 "Item that computes widths to generate spacing rods.
746 Calc dimensions for the Separating_group_spanner; this has to be
747 an item to get dependencies correct. It can't be an element_group
748 since these usually are in a different X_group
751 (property-description 'elements list? " -- list of items.")
754 (define sustain-pedal-interface
756 'sustain-pedal-interface
760 (define system-start-delimiter
762 'system-start-delimiter
765 (property-description 'collapse-height number? "")
766 (property-description 'thickness number? "thickness, measured in stafflinethickness")
768 ; Should collapse into (bracket . ((height . ) ... ))
770 (property-description 'arch-height number? "")
771 (property-description 'arch-angle number? "")
772 (property-description 'arch-thick number? "")
773 (property-description 'arch-width number? "")
774 (property-description 'bracket-thick number? "")
775 (property-description 'bracket-width number? "")
776 (property-description 'glyph symbol? "bar-line, bracket or brace")
779 (define text-spanner-interface
781 'text-spanner-interface
782 "generic text spanner"
784 (property-description 'dash-period number? "the length of one dash + white space")
785 (property-description 'dash-length number? "the length of a dash")
786 (property-description 'line-thickness number? "the thickness[stafflinethickness] of the line")
787 (property-description 'edge-height pair? "a cons that specifies the heights of the vertical egdes '(LEFT-height . RIGHT-height)")
788 (property-description 'edge-text pair? "a cons that specifies the texts to be set at the edges '(LEFT-text . RIGHT-text)")
789 (property-description 'type string? "one of: line, dashed-line or dotted-line") ; SYMBOL!!?
793 (define text-script-interface
795 'text-script-interface
802 (define tie-interface
805 "A tie connecting two noteheads."
807 (property-description 'staffline-clearance number? "don't get closer than this to stafflines.")
808 (property-description 'control-points list? "List of 4 offsets (number-pairs) controlling the tie shape")
809 (property-description 'heads pair? "pair of element pointers, pointing to the two heads of the tie. ")
810 (property-description 'details list? "alist of parameters for the curve shape")
811 (property-description 'thickness number? "thickness, measured in stafflinethickness")
812 (property-description 'x-gap number? "horizontal gap between notehead and tie")
813 (property-description 'direction dir? "up or down?")
814 (property-description 'minimum-length number? "minimum length in staffspace")
819 (define tie-column-interface
821 'tie-column-interface
822 "that sets tie directions in a tied chord"
826 (define volta-bracket-interface
828 'volta-bracket-interface
829 "Volta bracket with number"
831 (property-description 'bars list? "list of barline ptrs.")
832 (property-description 'thickness number? "thickness, measured in stafflinethickness")
833 (property-description 'height number? "in staffspace ")
836 (define span-bar-interface