I will probably be using my Raspberry Pi (running Ubuntu Mate) for remote desktop, but not all of the time. Sometimes I will want to plug it into a monitor. When it's not plugged into a monitor, I'd like it to default to 1024x600, and not the tiny 650-something by 420-something. This way I can use it comfortably via remote desktop. However, and here's the catch: when it's plugged into a monitor (I cannot predict the resolution of the monitor), I want it to use that monitor's resolution. This means I cannot just force hotplug and set the resolution that way, because that will not respect the monitor's resolution.
Any ideas?
Edit: I am using x11vnc, which means that the resolution that is shared is dependent on the screen size of the existing X desktop, which is in turn dependent on the monitor (or default resolution).
VNC, because otherwise the resolution is immaterial. You should clarify in your question. Depending on the VNC server, there should be settings for resolution. – Milliways Jan 02 '17 at 22:23