Webcast tool for a single window?

MrUmunhum · 12-29-2010, 04:10 PM

Hi group,

I want to provide a way of interactively Webcasting a single window. It must run on Linux and support Linux and Winders connections (maybe Macs too). No need for input from remote users, just real time output. I don't think that VNC would work the right way??

For example, using a GUI interface of the BamBoo Touch where I will write on the tablet and let other see what is happening in real time.

All ideas are welcome, but must be Open Source or GPL.

Thanks for your time.

gb2312 · 01-28-2011, 03:07 PM

Have you tried x11vnc -id option? From man x11vnc:

-id windowid

Show the X window corresponding to windowid not the entire dis‐
play. New windows like popup menus, transient toplevels, etc,
may not be seen or may be clipped. Disabling SaveUnders or
BackingStore in the X server may help show them. x11vnc may
crash if the window is initially partially obscured, changes
size, is iconified, etc. Some steps are taken to avoid this and
the -xrandr mechanism is used to track resizes. Use xwininfo(1)
to get the window id, or use "-id pick" to have x11vnc run xwin‐
info(1) for you and extract the id. The -id option is useful
for exporting very simple applications (e.g. the current view on
a webcam).

-sid windowid

As -id, but instead of using the window directly it shifts a
root view to it: this shows SaveUnders menus, etc, although they
will be clipped if they extend beyond the window.

MrUmunhum · 01-31-2011, 09:00 PM

Quote:

Originally Posted by gb2312

Have you tried x11vnc -id option? From man x11vnc:

-id windowid

Show the X window corresponding to windowid not the entire dis‐
play. New windows like popup menus, transient toplevels, etc,
may not be seen or may be clipped. Disabling SaveUnders or
BackingStore in the X server may help show them. x11vnc may
crash if the window is initially partially obscured, changes
size, is iconified, etc. Some steps are taken to avoid this and
the -xrandr mechanism is used to track resizes. Use xwininfo(1)
to get the window id, or use "-id pick" to have x11vnc run xwin‐
info(1) for you and extract the id. The -id option is useful
for exporting very simple applications (e.g. the current view on
a webcam).

-sid windowid

As -id, but instead of using the window directly it shifts a
root view to it: this shows SaveUnders menus, etc, although they
will be clipped if they extend beyond the window.

OK, I got ssh to start but when I 'pick' the window, it shows nothing.
What am I missing??
Looks like a good solution, if I can get it to work.

Code:

/usr/bin/ssh -C -t -p 22  user@127.0.0.1 'x11vnc -display :0.0 -usepw -id pick'
user127.0.0.1's password: 

  Please select the window for x11vnc to poll
  by clicking the mouse in that window.

  Picked: 0x5000007

31/01/2011 18:51:02 -usepw: found /home/user/.vnc/passwd
31/01/2011 18:51:02 x11vnc version: 0.9.8 lastmod: 2009-06-14
31/01/2011 18:51:02 Using X display :0.0
31/01/2011 18:51:02 rootwin: 0xae reswin: 0x4000001 dpy: 0x2042920
31/01/2011 18:51:02 
31/01/2011 18:51:02 ------------------ USEFUL INFORMATION ------------------
31/01/2011 18:51:02 
31/01/2011 18:51:02 Wireframing: -wireframe mode is in effect for window moves.
31/01/2011 18:51:02   If this yields undesired behavior (poor response, painting
31/01/2011 18:51:02   errors, etc) it may be disabled:
31/01/2011 18:51:02    - use '-nowf' to disable wireframing completely.
31/01/2011 18:51:02    - use '-nowcr' to disable the Copy Rectangle after the
31/01/2011 18:51:02      moved window is released in the new position.
31/01/2011 18:51:02   Also see the -help entry for tuning parameters.
31/01/2011 18:51:02   You can press 3 Alt_L's (Left "Alt" key) in a row to 
31/01/2011 18:51:02   repaint the screen, also see the -fixscreen option for
31/01/2011 18:51:02   periodic repaints.
31/01/2011 18:51:02 
31/01/2011 18:51:02 XFIXES available on display, resetting cursor mode
31/01/2011 18:51:02   to: '-cursor most'.
31/01/2011 18:51:02   to disable this behavior use: '-cursor arrow'
31/01/2011 18:51:02   or '-noxfixes'.
31/01/2011 18:51:02 using XFIXES for cursor drawing.
31/01/2011 18:51:02 GrabServer control via XTEST.
31/01/2011 18:51:02 
31/01/2011 18:51:02 Scroll Detection: -scrollcopyrect mode is in effect to
31/01/2011 18:51:02   use RECORD extension to try to detect scrolling windows
31/01/2011 18:51:02   (induced by either user keystroke or mouse input).
31/01/2011 18:51:02   If this yields undesired behavior (poor response, painting
31/01/2011 18:51:02   errors, etc) it may be disabled via: '-noscr'
31/01/2011 18:51:02   Also see the -help entry for tuning parameters.
31/01/2011 18:51:02   You can press 3 Alt_L's (Left "Alt" key) in a row to 
31/01/2011 18:51:02   repaint the screen, also see the -fixscreen option for
31/01/2011 18:51:02   periodic repaints.
31/01/2011 18:51:02 
31/01/2011 18:51:02 XKEYBOARD: all 28 "must have" keysyms accounted for.
31/01/2011 18:51:02   Not automatically switching to -xkb mode.
31/01/2011 18:51:02   If some keys still cannot be typed, try using -xkb.
31/01/2011 18:51:02   Also, remember "-remap DEAD" for accenting characters.
31/01/2011 18:51:02 X FBPM extension not supported.
31/01/2011 18:51:02 X display is capable of DPMS.
31/01/2011 18:51:02 --------------------------------------------------------
31/01/2011 18:51:02 
31/01/2011 18:51:02 Default visual ID: 0x21
31/01/2011 18:51:02 Read initial data from X display into framebuffer.
31/01/2011 18:51:02 initialize_screen: fb_depth/fb_bpp/fb_Bpl 24/32/2400
31/01/2011 18:51:02 
31/01/2011 18:51:02 X display :0.0 is 32bpp depth=24 true color
31/01/2011 18:51:02 
31/01/2011 18:51:02 Autoprobing TCP port 
31/01/2011 18:51:02 Autoprobing selected port 5900
31/01/2011 18:51:02 Xinerama: Library libXinerama is not available to determine
31/01/2011 18:51:02 Xinerama: the head geometries, consider using -blackout
31/01/2011 18:51:02 Xinerama: if the screen is non-rectangular.
31/01/2011 18:51:02 fb read rate: 91 MB/sec
31/01/2011 18:51:02 fast read: reset wait  ms to: 10
31/01/2011 18:51:02 fast read: reset defer ms to: 10
31/01/2011 18:51:02 screen setup finished.
31/01/2011 18:51:02 

The VNC desktop is:      acer64.mt-umunhum-wireless.net:0
PORT=5900

krunge · 02-01-2011, 09:18 AM

Quote:

Originally Posted by MrUmunhum

OK, I got ssh to start but when I 'pick' the window, it shows nothing.
What am I missing??
Looks like a good solution, if I can get it to work.

Code:

/usr/bin/ssh -C -t -p 22  user@127.0.0.1 'x11vnc -display :0.0 -usepw -id pick'
user127.0.0.1's password: 

  Please select the window for x11vnc to poll
  by clicking the mouse in that window.

  Picked: 0x5000007

  ...

Next you need someone to connect from a remote computer with a VNC viewer. (E.g. vncviewer your-computer-name-or-ip.net:0 )

MrUmunhum · 02-01-2011, 06:27 PM

OK guys, thanks for all of your help. I figured it out and your solution is exactly what I need.

For the forum. It is a two step process and can be debugged on the same PC.

start your program, I used mypaint.
xwininfo to get the window ID.
start x11vnc -id (from above) -viewonly -usepw -display :0 -shared
start vncviewer IP-address // from local or remote

That's it, works great.

Thanks again.

krunge · 02-05-2011, 09:55 PM

The "-id pick" should work too instead of running xwininfo(1) manually. The remote user would have to connect with the vncviewer after you have clicked on the desired window.