[GRASS-dev] why d.vect.thematic won't run on WinGRASS - d.mon problem

Michael Barton michael.barton at asu.edu
Wed Jan 23 22:54:45 EST 2008


On Jan 23, 2008, at 6:42 PM, Glynn Clements wrote:

>
> Michael Barton wrote:
>
>> In order for d.vect.thematic to run in the GUI (the only way it will
>> work in WinGRASS), it has to start and stop the PNG monitor.
>>
>> To do this, it has to run d.mon--i.e., d.mon start=png and d.mon
>> stop=png.
>>
>> However, d.mon will not run in WinGRASS, probably because it does not
>> have x11. I am betting that d.mon ALWAYS checks for an x11 monitor
>> when it attempts to do something.
>
> Nope. d.mon doesn't work in WinGRASS because monitors don't work in
> WinGRASS. This isn't due to the lack of X11 (which only affects
> XDRIVER), but the lack of Unix-style sockets (by which, I mean sockets
> which work with read() and write(), not necessarily Unix-domain
> sockets).
>
> I tried modifying the code to use TCP sockets, but I couldn't get it
> to work. Well, using TCP sockets works on Unix, but the process of
> converting the WinSock SOCKET to an fd which works with MSVCRT's
> read() and write() didn't seem to work.
>
> So, unless someone is willing to invest the effort to replicate the
> communication between libraster and the drivers, monitors will remain
> unavailable in the native WinGRASS version.

I was afraid that you were going to say something like that

>
> If you just want d.vect.thematic to work with WinGRASS, changing it to
> use GRASS_RENDER_IMMEDIATE=TRUE instead of "d.mon start=PNG" would
> probably be less work than getting monitors working.

In fact, we recently had to change d.vect.thematic to set  
GRASS_RENDER_IMMEDIATE=FALSE so that it's multiple iterations of  
d.vect would composite in the PNG monitor and then be output as a PNG  
to the GUI.

If we want it to work with Windows, it will take considerably more  
coding. we have to set GRASS_RENDER_IMMEDIATE=TRUE, track all  
iterations of d.vect and use g.pnmcomp to composite them all. It  
might be possible to make use of existing TclTk code to do some of  
this, but I doubt it.

Michael
____________________
C. Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>





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