Re: Undo framework

[Sven Neumann <sven gimp org>]

Hi,

On Tue, 2007-09-25 at 08:16 -0400, Jody Goldberg wrote:

> Undo comes with Redo, which is sufficient information to make a
> replay a modification from a known state.

Not necessarily. A common approach to Undo/Redo is to store the
information before the operation on the undo stack. Then, when the user
decides to undo, you push the information at this point to the redo
stack and undo by going back to the saved state. This allows you to Undo
and Redo, but it is not sufficient information to replay a modification
from a known state. Not unless you actually reached this point by undo
operations.


Sven