[Therion] How to use user-defined symbols

[Bill Gee]

Hi Martin -

Thanks!  Just one error ...  The definition is p_u_stalagmaflat_AMER.  You got 
the u and p reversed.  Took me a couple of hours to figure that one out today, 
but I eventually got it.

The new symbol is working for me.  It goes on the map like it should.  I have 
two followup questions:

1) The map legend labels the symbol as "point u:stalagmaflat_AMER".  I tried to 
use a text line in the thconfig file, but it has no apparent effect.  If I put it 
inside the layout/endlayout pair, therion throws an error.  If I put it 
outside the layout/endlayout section, then no error - and no change.    

2) It would be handy to split the Metapost code out to an include file.  I 
tried to use both source and input to read a file, but therion did not like 
them.  Is there a way to do this?

The only example I found in the Wiki has the entire layout section in a 
separate file.  I just want to split the Metapost code out.

Bill Gee


On Sunday, February 02, 2014 23:06:21 Martin Sluka wrote:
> Bill,
> There are two kinds of symbols in Therion - first one are symbols which are
> included to Therion in time of compilation - like symbol "stalagmite".
> Second kind are user symbols. The definition of user symbol should be like:
> 
> def u_p_stalagmaflat_AMER (expr pos,theta,sc,al) =
> 
> In XTherion you call it as:
> 
> point u:stalagmaflat_AMER
> 
> Red are symbols which definition is not known.
> 
> M.
> 
> 
> 
> Odesláno z iPhonu
> 
> 2. 2. 2014 v 22:00, Bill Gee <bgee at campercaver.net>:
> > Hello everyone -
> > 
> > I have been struggling for the last several days trying to figure out how
> > to build and use my own symbols.  I need a symbol for two kinds of
> > formations - Stalactiflats and Stalagmaflats.  These are basically
> > stalagmites which are fat (several feet diameter) and flat on top like a
> > table (or flat on the bottom).
> > 
> > It appears there are two problems to solve.  The first, which I address in
> > this question, is how to get xTherion to use a custom symbol.  The second
> > is to figure out how to draw the symbol in Metapost.  For now I am
> > ignoring the second problem.  One step at a time!
> > 
> > After spending several hours going through Therion By Example, I was able
> > to get a custom symbol to work, but only by replacing an existing symbol.
> >  I used the NSS "gradient point" example.
> > 
> > Changing the Metapost code as shown does not produce any error messages.
> > However, it also does not produce a symbol in the PDF output.  All I get
> > is a red dot.
> > 
> > ===============
> > 
> >        code metapost
> >        
> >        def p_stalagmaflat_AMER (expr pos,theta,sc,al) =
> >        
> >          U:=(.15u, .4u);
> >          T:=identity aligned al rotated theta scaled sc shifted pos;
> >          pickup PenC;
> >          
> >          #Left Hand side
> >          thdraw (-.3u, -.2u) -- (-.7u, .1u);
> >          thdraw (-.2u, -.1u) -- (-.4u, .6u);
> >          
> >          #Centerline
> >          thdraw (0u, 0u) -- (0u, .9u);
> >          
> >          #Right side
> >          thdraw (.3u, -.2u) -- (.7u, .1u);
> >          thdraw (.2u, -.1u) -- (.4u, .6u);
> >        
> >        enddef;
> >      
> >      initsymbol ("p_stalagmaflat_AMER");
> >   
> >   endcode
> > 
> > ==================
> > 
> > Since I am not replacing an existing symbol, I leave out the
> > "symbol-assign" line.
> > 
> > In xTherion I try to use this by inserting a point of type "u" and adding
> > an option "-subtype stalagmaflat".
> > 
> > I think this is where I am missing something ...  How to call the custom
> > symbol with a "u" point.  Is this the right syntax?
> > 
> > In the worst case I suppose I could set it up to replace a symbol that I
> > won't use for this cave - a ladder, for example.  That would probably
> > cause quite a bit of confusion down the road, so I would much prefer to
> > avoid it.
> > 
> > I am using Therion 5.3.13 on 64-bit Fedora 20.
> > 
> > Thanks - Bill Gee
> > _______________________________________________
> > Therion mailing list
> > Therion at speleo.sk
> > http://mailman.speleo.sk/mailman/listinfo/therion
> 
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