Zooming in/out for visually impaired users
We are developing content for a Government client in Ontario who require AODA standards. One thing I can't seem to figure out how to do well is grant functionality to the user so that they can zoom/resize the current slide proportionally such that all the content keeps their positions, but the size of them doubles, or increases by a third.
Is there a good way to apply this function universally across all slides? I know there is a zoom feature in SL 2 but how can I set it up to achieve zoom for all objects on screen at once?
Thanks very much for your input.