Update undo draft

[abique]

No description provided.

[tim-janik]

Glancing over this draft, I have two questions:

1. When undo/redo processing is left to the host, how does the host learn that a new undo step should be added to the undo history, in case a user makes a change purley through the plugin UI? Consider hosts that continuously display a list of recorded undo history (e.g. like gimp's "Undo History" tab).

2. I am not sure the API allows the host to provide a fully linearized undo/redo history as described in TheGURQ. Do you have thoughts on that? https://github.com/zaboople/klonk/blob/master/TheGURQ.md

[abique]

Glancing over this draft, I have two questions:

1. When undo/redo processing is left to the host, how does the host learn that a new undo step should be added to the undo history, in case a user makes a change purley through the plugin UI? Consider hosts that continuously display a list of recorded undo history (e.g. like gimp's "Undo History" tab).

The plugin calls host->begin_change() and host->change_made() or host->cancel_change().

2. I am not sure the API allows the host to provide a fully linearized undo/redo history as described in [TheGURQ](https://github.com/zaboople/klonk/blob/master/TheGURQ.md). Do you have thoughts on that? https://github.com/zaboople/klonk/blob/master/TheGURQ.md

It is fully linearized.