How to add undo functionality for a plugin

• Jun 20, 2013 - 20:13

I noticed that I cannot undo the action of my plugin. Is there some code that I have to add?

Thanks for the help,
Ruud

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• Jun 20, 2013 - 22:25

It seems that there exist curScore.startUndo() and curScore.endUndo() calls in the 1.X version of the framework - at least, I see those defined in the Score object and being used by lots of plugins. It does seem to work, although I've never really experimented to see how well.

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• Jun 22, 2013 - 12:54

I have tried to use the undo calls but it does not work. I tried debugging but that gave strange results. First of all, when I had the standard applyToNotesInSelection in a separate file it did not switch to that file but showed me the main file that called it. Secondly, when I stepped it stopped with an error after the first note of the selection (with a blue box) but when I run it applies the function to all selected notes.
Is there anyone with experience on this point? I did this with version 1.3 on Windows XP with a dutch language setting.

Thanks for the help,
Ruud

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• Jun 22, 2013 - 15:50

Posting an example you are having trouble with would help. Perhaps I suspect some operations are inherently not undoable. But I know it works for most of the plugins I've worked on - Break Every X Measures, Cue Notes, Explode/Implode, Slash Notation Styles, etc. So maybe look at one of those to see if you are using the calls differently.

Oh, and I have no idea if plugins even support the idea of separating functions into different files, but suspect not, at least for 1.3. I think 2.0 might.

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• Jun 22, 2013 - 17:23

Calling a function in another script file does work. It searches first in the folder where the calling script is. It just doesn't show in the debugger. The code I used is below and calls the standard function applyToNotesInSelection that is in the Development/Plugin Development/Howto.
Since the enharmonic shift will be in 2.0 this is now only for my understanding, so it is not necessary to put in a lot of effort.

// shift one note
function shiftUp(note)
{
var newtpc = note.tpc + 12;
if (newtpc <= 33)
{
note.tpc = newtpc;
}
};
function init() {};
function run()
{
curScore.startUndo();
// do the shift for all notes in selection using the standard code snippet
applyToNotesInSelection(shiftUp);
curScore.endUndo();
};
function close() {};

var mscorePlugin =
{
majorVersion: 1,
minorVersion: 1,
menu: 'Plugins.enharmonicShiftUp',
init: init,
run: run,
onClose: close
};

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