Implement scale option for clone mode

Submitted by b3nmore

Assigned to Jérôme Guelfucci

Link to original bug (#9759)

Description

Created attachment 4853 Script to switch an external monitor in scaled clone mode on and off.

Some people get confused when using clone mode with different monitor resolutions, because the mouse cursor can 'vanish' on the lower one.

How about adding a scale option to the clone mode, which scales the higher resolution to fit the lower resolution monitor via the randr scale function. Note, that this is different to the already implemented mirror option, because it would preserve the native resolution on the high res output.

Usage scenario: Dia show on an external HDTV, to ease the task both monitors should show the same (real cloning), but you wouldn't want to loose the native resolution of the tv.

Slight disadvantage: Scaling means of course that everything looks smaller on the lower res output.

I've attached a script to demonstrate scaled cloning (you may have to adapt the name of the display ports to your actual setup $INT, $EXT).

Attachment 4853, "Script to switch an external monitor in scaled clone mode on and off.":
exmonswitch.sh