In whiteboard enable undo to undo a clear

[GoogleCodeExporter]

What steps will reproduce the problem?
1.  Draw some shapes
2.  Click erase all button
3.  Click undo

What is the expected output? What do you see instead?

Expect that undo would undo the erase all.  See

  https://groups.google.com/group/bigbluebutton-dev/browse_thread/thread/ba4e48dcdec19bd6#

Original issue reported on code.google.com by ffdixon@gmail.com on 16 Mar 2013 at 11:39

[GoogleCodeExporter]

Original comment by ffdixon@gmail.com on 16 Mar 2013 at 11:40

• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

Original comment by mcmarkos86 on 18 Mar 2013 at 6:00

• Changed state: Accepted

[GoogleCodeExporter]

I think that in order to accomplish this, we need to change a little bit how 
the shapes are stored... Currently, if we do an "undo" action the shape is 
removed from an arraylist...

probably, a better approach would be that all the shapes should be stored, and 
each shape has a property called "visible", and when it's true, the shape is 
drawn otherwise is not drawn... This will also enable us to put a re-do 
button...

what do you think?

Original comment by mcmarkos86 on 1 Apr 2013 at 10:33

[GoogleCodeExporter]

What if we store the deleted shapes into an array with max 5 elements? It will 
just keep the latest 5 undos.

But yes, this doesn't address the clear. 

What you suggest is the proper way I believe. How much change do we need to do 
on the server side?

Original comment by ritza...@gmail.com on 2 Apr 2013 at 12:15

[GoogleCodeExporter]

Original comment by ffdixon@gmail.com on 15 Dec 2013 at 2:35