NAME

xwatchwin - watch a window on another X server

SYNOPSIS

xwatchwin [-v] [-u UpdateTime] DisplayName { -w WindowID | WindowName }

DESCRIPTION

xwatchwin allows you to peek at a window on another X server. To use it, you must specify the display name of the machine you want to watch, then the name of the window on that machine. Xwatchwin will attempt to connect with the X server hostname:0.0, and if successful, will try to retrieve a copy of the window in which you specified interest.

You may specify the window you want to watch either by name or by its window id, usually a hexidecimal number. Usually specifying the window by name is simpler, although not all windows have names associated with them; in that case you must use the window id option.

If the window you want to watch is not in a viewable state, xwatchwin will tell you so and exit. If while you are watching a window it becomes 'unviewable', xwatchwin will wait until the window becomes 'viewable' again.

xwatchwin was written as an aid to a class for people learning to use X. The idea is that the instructor would type into an xterm window on his/her display and the students would use xwatchwin to see what the instructor typed. The students could then type the same thing in their own terminal windows. Hopefully others will find equally (if not more) constructive uses.

OPTIONS

-u updatetime

This option specifies how often (in seconds) you want to get a new copy of the window you're watching. It is in effect a 'sample rate'. By default, xwatchwin updates your copy of the window as often as it can. The time it takes to actually do the update is dependent on the speed of the X server on both machines, the speed of the intervening network, and other factors.

-w windowID

This option specifies the window you want to watch by number, for example, "0x50000b". Use the xlswins(1) command to get a list of window id's and possibly their names on the remote server.

You must specify a window to watch either by name or by id. Specifying a window to watch by name is usually easier if you know what you're looking for.

EXAMPLES

If there is an X server on the remote machine "crow" and if on that server there is a window called "X Terminal Emulator", you can watch that window by typing

xwatchwin crow X Terminal Emulator

If there is a window on "crow" that has no name but has a window id of "0x50000b", you can watch it by typing

xwatchwin -w 0x50000b crow

If you want to get new copies of a window only every 30 seconds, you can do so by typing

xwatchwin -u 30 -w 0x50000b crow

BUGS

xwatchwin doesn't support the -display option. You must set the display on which the xwatchwin window is created by changing your DISPLAY environment variable.

If the window you're watching is resized while xwatchwin is getting a new copy of that window, the program will crash. The smaller your update interval, the more likely you are to experience this bug (although it hasn't happened all that often to me).

xwatchwin can now deal with two displays of different depths. There is special-case code for the conversions between 1-bit displays and 8-bit displays (either direction) which may garble the image on some machines. The general case code should work on anything, albeit somewhat more slowly. One note: ABSOLUTELY no attempt is made to make the colors match up. If you're on a 5-bit display, and you're monitoring someone elses 8-bit display, the conversion just takes his 8 bits and chops the top 3 bits off, and puts it on the screen. Maybe in the next version...

COPYRIGHTS

AUTHORS

Light-weight version by Q. Alex Zhao azhao@cc.gatech.edu.

Display depth conversion code added by John Bradley bradley@cis.upenn.edu.

Original version by George D. Drapeau, Stanford University, Academic Information Resources / Systems Development, drapeau@jessica.stanford.edu.