Re: [PyX-user] Add new symbol

[Andre W. <wo...@us...>]

Hi,

On 09.02.05, Joerg Lehmann wrote:
> See the attached example how to do this.

I think this is just about the right time to create a graphstyle
example directory. We really should show to the people, how easy they
can construct and work with own graph styles.

> from pyx import *
> 
> # The new symbol: just a vertical line
> #
> # Note that, as for all internal PyX methods, coordinates are passed in PS
> # points, and we hence have to use the corresponding path classes.
> def _linesymbol(c, x_pt, y_pt, size_pt, attrs):
>     c.draw(path.line_pt(x_pt, y_pt-0.5*size_pt, x_pt, y_pt+0.5*size_pt), attrs)
> 
> # the symbol style expects a changeable attribute as argument, 
> # so we create a dummy one consisting of a single symbol
> linesymbol = attr.changelist([_linesymbol])

Note that you never need to plug in changeable attributes when you
don't want to have it changed.

> # example usage
> g = graph.graphxy(width=10, 
>                   x=graph.axis.lin(min=0, max=10))
> 
> g.plot(graph.data.function("y=x**2"), [graph.style.symbol(symbol=linesymbol)])

You could use _linesymbol directly here as well ...

> g.writeEPSfile(__file__[:-3])

The __file__ seems to become common use. We (Jörg and I) have seen it
on this list first. It's really nice ...


André

-- 
by  _ _      _    Dr. André Wobst
   / \ \    / )   wo...@us..., http://www.wobsta.de/
  / _ \ \/\/ /    PyX - High quality PostScript figures with Python & TeX
 (_/ \_)_/\_/           visit http://pyx.sourceforge.net/