Is this what beginUndo is for?

Scripting
1

I have a complicated script that does a bunch of stuff to a glyph’s shape. Is there a way to set a kind of checkpoint in the script so that undo would undo everything the script did after the checkpoint? Is this what beginUndo() is for? If so, how do I use it?

The use case is a script that has a last step of calling the Noodler filter. With 95% of glyphs it gets me the results I want, but for the other 5% I would like to undo the Noodler filtering done by the script, adjust the paths for a better result, and then manually redo the filter.

2

You surround all the individual steps (that are supposed to be undoable separately) with:

glyph.beginUndo()
dosomething(glyph)
glyph.endUndo()

.

3

If you use this, you need to wrap everything you do to the glyph. You can however have several groups.
This is not good:

dosomething(glyph)
glyph.beginUndo()
dosomething(glyph)
glyph.endUndo()

This is OK

glyph.beginUndo()
dosomething(glyph)
glyph.endUndo()

glyph.beginUndo()
dosomething(glyph)
glyph.endUndo()
1 Like
4

The fact that my script creates new glyphs along the way is making this confusing for me.
Here’s an outline of the script and where I’ve put the undo stuff, but doesn’t appear to be working. My goal is to be able to undo the filtering in glyphs on which the script is run and on new glyphs it creates.

for layer loop
	layer.parent.beginUndo()
	do stuff to layer
	do other stuff to layer
	layer.parent.endUndo()
	if loop that creates certain variant glyphs
		if loop that collects some of those glyphs
		for glyph in collected glyphs loop
			glyph.beginUndo()
			run filter on glyphs first layer
			glyph.endUndo()
	else
		layer.parent.beginUndo()
		run filter on layer
		layer.parent.endUndo()
5

why is the if loop that creates certain variant glyphs inside the for layer loop. So depending on the if loop that collects some of those glyphs line, it seems that this collecting is done for each layer, so it might be applied too often.

1 Like
6

Aha, you’re right, the structure is flawed. I think I had it in my head that the script needed one overarching iteration but of course that’s not true.

7

But maybe I do want that iteration: if I select /n/o in text mode, I do want the script to produce /n.init, /n.medi, /n.fina, /o.init, /o.medi, and /o.fina.

8

It is difficult to help with such a rudimentary code. But undo wise, it looks quite right.

Maybe you make two scripts. One making the extra glyphs and one applying the filter?