Older X.org and XFree86 used to have this neat feature where pressing Ctrl+<numpad +> and Ctrl+<numpad -> would cycle through the screen modes defined in your config file in the “Screen” section, effectively switching screen modes on the fly and letting you pan around the full virtual screen size with the mouse.
This was a really useful feature for zooming in on small details, or to blow up videos without incurring high CPU overhead.
But since about X.org 1.7 this feature seems to be missing. I’ve been researching and discovered why it’s missing, and what to do about it.
This post is also available at my personal web site: http://milosophical.me/blog/2009/02/20/xming-screen-size.html
My work’s notebook (Windows XP) is running Xming as it’s X11 server, and it travels between work, home and on the train.
My work office has a docking station and a rotating second display. Typically if I start Xming with this display plugged in, Xming will adjust it’s screen size to use both displays, but if I start it without the screen plugged in, it’ll size to just the notebook screen. If I later add the 2nd screen (by docking the notebook), Xming won’t use it without a restart. Also if I rotate the screen, only the top 1200 pixels will be used by Xming.
The solution is to specify a screen size to begin with that is as wide and tall as both of the screens. On my docked notebook the two displays are the notebook’s display (1920×1200 pixels) and 2nd display (1600×1200 pixels, which rotates to 1200×1600). So that means the combined screen width is 3520 pixels, and the tallest screen hight is 1600 pixels. Specify this to Xming when it starts:
path\to\xming.exe :0 -clipboard -multiwindow -screen 0 3520x1600
Now I can add/remove/rotate the second screen and still use all of it without restarting Xming.