How to уменьшает double desktop to one that fits the display screen?

In Ubuntu, I have the problem that my desktop is spanning beyond what my display screen шоу. Specifically, half of my desktop is hidden from view. This вызови я problems with windows that пашите opening on the hidden part or in укради when I accidentally move windows to the hidden part.

I would like to know how to уменьшает the desktop space such that all of the desktop could be viewed and не hidden part would exist any обитайте.

Also, will it be possible for this to be подарил without changing the size of the icons of the desktop?

The output of xrandr:

Screen 0: minimum 320 x 200, current 2390 x 768, maximum 32767 x 32767
LVDS1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
 1366x768 60.0*+ 
 1360x768 59.8 60.0
 1024x768 60.0
 800x600 60.3
 56.2 640x480 59.9 
VGA1 disconnected (normal left inverted right x axis y axis) 
HDMI1 disconnected (normal left inverted right x axis y axis) 
DP1 disconnected (normal left inverted right x axis y axis) 
VIRTUAL1 disconnected (normal left inverted right x axis y axis)