MuseScore 3.3: Plugin API Update

A brief list of new features in plugins API in MuseScore 3.3:

• Expose Align enumeration. Can be used to assign values to text alignment properties of elements (align, beginTextAlign etc., see Element type documentation).
• Expose note play events:
  • Add PlayEvent type
  • Add Note.playEvents property. Play events can be read from this list. This is a writable list so events can also be appended with push() function and removed by clearing a list (n.playEvents = []). See list QML type documentation.
  • Add Chord.playEventType property which controls whether play events are generated automatically by MuseScore or fully controlled by a user (or a plugin). Usually this property is assigned automatically, assign it manually to PlayEventType.Auto to make play events be reset by MuseScore later.
• Adding and removing elements:
  • Add Chord.add() and Chord.remove() functions. They were available in MuseScore 2 and allow to add individual notes and other elements to existing chords.
  • Add removeElement() function.
  • Add support for more types to Cursor.add() function (commit)
• Expose list of selected elements to plugins:
  • Add Score.selection property
  • Add Selection type providing a read-only access to the list of selected elements.
• Restore some properties available in MuseScore 2 (and add some new ones):
  • Add Element.parent property.
  • Add Element.posX and Element.posY read-only properties providing an information about an element position.
  • Add Note.tieBack, Note.tieForward, Note.firstTiedNote, Note.lastTiedNote properties and Tie type.
• Comparing variables:
  • Add ScoreElement.is() and Excerpt.is() functions. They allow to check whether different plugin objects correspond to the same internal MuseScore object which is not currently possible to determine correctly with == or === operators.
• Notifying plugins of score changes:
  • [Experimental] Add onScoreStateChanged handler. Mostly useful for plugins that are supposed to be used interactively (like "dock" type plugins). See the documentation for usage example.