Experimental Physics and
Industrial Control System

Johannes van Zeijts <[email protected]> · Tue, 07 Apr 1998 08:51:52 -0400

Pete Jemian wrote:
> 
> Paul Sichta wrote:
> >
> >2)  Is the tcl/tk interface applicable to this type of function ?
> >
> 
> Do not advise using et_wish for this type of work.
> Since BLT was upgraded from v1.8 to (now) 2.3,
> support for BLT vectors was changed.  This change broke
> the mechanism to interface with the EPICS waveform record
> and (to my knowledge) noone has repaired it.
> Since using et_wish for some applications, I can say
> that it is nice for many things, gives good control over
> the user interface, but is very slow when you have
> a high update rate, such as with a strip chart or plotting
> tool.
> 

I have used the BLT extension to tcl/tk with great success (both for own use and
in the control room). You ofcourse have to write the interface code in C instead
of only using tcl. After you do that correctly you can get as fast live updates as
StripTool or any other X11 plotting tool, with the same cpu usage. There is
definitely no inherent slowness to BLT, and as you note it gives you a lot more
flexibility than hardwired plotting code.

All my interface code at the moment runs through CDEV, but I can show you the code
if you are interested.

	-Johannes

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System