I have been searching everywhere and can't seem to find any information as to why I get the error:
Xlib: extension "XFree86-VidModeExtension" missing on display ":0.0".
Unable to query video extension version
when I run xgamma from xterm. It wasn't until I found this site that I realized that the configuration file "wasn't needed" by X11 on Darwin, yet that would be the place to turn on the extension? Is xgamma an invalid tool for the mac?
Torrey T. Lyons
Yes XFree86-VidModeExtension" is not enabled or supported in XDarwin. As such xgamma won't work on Mac OS X. To accomplish the same thing you should use the native Mac OS X tools such as setting the Color options in the Displays System Preference.
Ah well, that kinda blows. The idea is to build a little tool that exists in linux where I can swing the monitor gamma around and reset it back to normal afterwards for film work. I don't want to change the calibration or open system prefs to do that. It would be nice if it was documented somewhere! At least somewhere by searching VidModeExtention or xgamma.
Thanks very much for the reply. This has been driving me nuts!