input/test/pushproperty.ly

   1 \version "1.3.117";
   2
   3 %{
   4
   5 Look at ly/engraver.ly for inspiration on which XXXX
   6 there are.
   7
   8 Generally, you can find interesting element properties associated with
   9 \property in scm/generic-property.scm. For example, this file contains
  10
  11         (define generic-stem-properties
  12           (cons 'stem-interface
  13                 (list
  14                  (list 'stemVerticalDirection dir? 'direction)
  15                  (list 'verticalDirection dir? 'direction)
  16                  (list 'stemLength number? 'length)
  17                  (list 'flagStyle string? 'flag-style)
  18         )))
  19
  20
  21 which means that setting \property stemVerticalDirection overrides
  22 setting \property verticalDirection, and that both have the effect of
  23 setting `direction' in Stem object. You can use \overrideproperty for
  24 setting stem directions by doing.
  25
  26
  27         \overrideproperty #'(Stem) #'direction #1
  28
  29 (#-1 if you want down).
  30
  31 A modest amount of memory is involved each time you do a
  32 \overrideproperty. If you do \revertproperty in the right order (reversed
  33 from \overrideproperty), then \revertproperty doesn't cost memory.
  34
  35 Correct:
  36
  37         \overrideproperty #'(  ... ) #'symbolA #valueA
  38         \overrideproperty #'(  ... ) #'symbolB #valueB
  39         \revertproperty #'(  ... ) #'symbolB
  40         \revertproperty #'(  ... ) #'symbolA
  41
  42 Incorrect (\revertproperty costs memory):
  43
  44         \overrideproperty #'(  ... ) #'symbolA #valueA
  45         \overrideproperty #'(  ... ) #'symbolB #valueB
  46         \revertproperty #'(  ... ) #'symbolA
  47         \revertproperty #'(  ... ) #'symbolB
  48
  49 You can use identifiers, eg.
  50
  51     slursUp = \context Voice \overrideproperty '(Slur)
  52             #'direction  #1
  53     slursBoth = \context Voice \revertproperty '(Slur)
  54
  55 %}
  56
  57 \score { \notes
  58 \relative c' {
  59         c4-.(
  60         \property Voice.Dots \override #'direction =  #-1
  61         \property Voice.Stem \override #'direction =  #-1
  62         \property Voice.noteColumnProperties \override #'direction =  #-1
  63         \property Voice.Stem \override #'direction =  #-1
  64
  65         ) c4-. (
  66         ) c4-. (
  67          \property Voice.Slur \override #'direction =  #-1
  68         ) c4-. (
  69
  70         \property Dots \revert  #'direction
  71         \property Stem \revert #'direction
  72         \property Script \revert #'direction
  73         \property Text \revert #'direction
  74
  75          ) c4-.  () c4-.
  76 }
  77
  78 \paper {
  79 \translator { \VoiceContext
  80         NoteHead \override #'font-relative-size =  #-2
  81 }
  82 }
  83 }