[ltp] Switching X screen res's "on the fly"

[Richard Neill]

One more thing you may need to worry about is the frequency range. I 
actually need this in my XF86Config4 file:
     HorizSync 20-140
     VertRefresh 50-275
Yes, I know they look outrageous, but it's the only way to get at the 
lower resolutions.

I have more details and a helpful script at 
www.richardneill.org/a22p-mdk9-1.html#x

Best wishes

Richard


Rob Mayoff wrote:
> +---------- On Sep 30, Crawford Rainwater said:
> | I am using RedHat 9.0 with the 2.4.20-20.9 kernel for reference purposes
> | with gdm running Gnome and KDE (using Gnome primarily).  When I use the
> | Gnome "System Settings" (aka redhat-config-xfree86) to do this, it
> | crashes X, so I am stuck at 1600x1200 (which is not compatible with most
> | LCD projectors of course).
> 
> First, all of the resolutions you want to use must be listed on the
> "Modes" line of the "Screen" section of your /etc/X11/XF86Config. For
> example, here's the "Screen" section of the XF86Config on my A30p:
> 
> Section "Screen"
> 	Identifier "Screen0"
> 	Device     "Videocard0"
> 	Monitor    "Monitor0"
> 	DefaultDepth     24
> 	SubSection "Display"
> 		Depth     24
> 		Modes    "1600x1200" "1400x1050" "1280x1024" "1280x960" "1024x768" "800x600" "640x480"
> 	EndSubSection
> EndSection
> 
> Second, there are two ways to change X's resolution on the fly using
> programs. The programs are "xvidtune" and "xrandr".
> 
> Most window managers let you bind keys to execute specific programs. To
> do so in Metacity (the default Gnome WM in Redhat 9), use gconf-editor.
> For example, set /apps/metacity/global_keybindings/run_command_4 to
> "<Ctrl><Alt>slash" and set /apps/metacity/keybinding_commands/command_4
> to "xvidtune -next".
> 
> xvidtune changes the video mode without changing the root window size.
> So if you change to a resolution smaller than the size of your root
> window, the physical screen acts as a window onto a larger virtual
> screen, and scrolls when you try to move the mouse past a screen edge.
> The commands to use are "xvidtune -next" and "xvidtune -prev".
> 
> xrandr changes the video mode and the root window size. The window
> manager (if it supports the RANDR extension, which metacity does)
> detects the change and moves windows as necessary if they'd be outside
> the root window. The command is "xrandr -s N", where "N" is the mode
> number, or "xrandr -s WxH", where "WxH" is the size.
> 
> 

-- 
rn214@hermes.cam.ac.uk  **  http://www.richardneill.org
Richard Neill, Trinity College, Cambridge, CB21TQ, U.K.