undo & redo support about fabric.js

[kangax]

The undo/redo support is somewhat unrelated to fabric itself. The behavior of history management will likely vary based on your needs. Which actions are added to history stack? When an object is moved, is every pixel tracked and added to a history? Or is move action added to history only when object is "stopped" (mouse up)? How about other object modifications — scaling, rotation — are they considered undoable actions as well?

I think that history management should be implemented separately of fabric, according to specific requirements. It can be plugged into fabric via events that library exposes — http://kangax.github.com/fabric.js/demos/events/

[raichu]

There argument here is that here is no "one true way", but it's not true.
I don't think there are any ambiguities here at all.
Other that "every pixel tracked" action, everything you mentioned is undoable in all (vector) image editing tools I have ever seen.
It's the norm to consider mouse drag actions to start with mouse down and and end with mouse up. And simply down event for buttons. Mouse buttons don't auto-repeat, and keyboard auto-repeat is handled by the window manager such that the application received a stream of button down events.

It'd solve the problem for users.

[raichu]

for reference: #23 and #582

[deveshsinghal22]

This Fiddle can be useful
http://jsfiddle.net/SpgGV/9/