🚀 go-pugleaf

You can't 'cancel' an event that has already occurred. The best you can do is 
'undo' it.

Here's some code for undo and redo. The lowercase versions traverse the history 
list (from the History Palette). The uppercase versions are the same as 
selecting 'Undo' and 'Redo' from the Edit menu.

There is currently no practical way of recording the Crop event for later 
playback unless you actually invoke the Crop command from within your script.

-X


// extracted from xtools/xlib/stdlib.js

Stdlib = {};

cTID = function(s) { return app.charIDToTypeID(s); };
sTID = function(s) { return app.stringIDToTypeID(s); };

Stdlib.doEvent = function(id) {
   return app.executeAction(id, new ActionDescriptor(),  DialogModes.NO);
};

Stdlib.hist = function(dir) {
   function _ftn() {
     var desc = new ActionDescriptor();
     var ref = new ActionReference();
     ref.putEnumerated(cTID("HstS"), cTID("Ordn"), cTID(dir));
     desc.putReference(cTID("null"), ref);
     executeAction(cTID("slct"), desc, DialogModes.NO);
   }

   _ftn();
};
Stdlib.undo = function () {
   Stdlib.hist("Prvs");
};
Stdlib.redo = function () {
   Stdlib.hist("Nxt ");
};
Stdlib.Undo = function () {
   Stdlib.doEvent(cTID("undo"));
};
Stdlib.Redo = function () {
   Stdlib.doEvent(sTID('redo'));
};