Re: [PyX-user] clipping of symbol plots

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

Hi,

On 01.11.05, Arnd Baecker wrote:
> when plotting with symbols, part of the symbol
> may be outside of the plot region.
> Is there a simple way to clip any those parts away?
> 
> (I tried to change the code so that
> a graphxy can pass on `attrs` to the underlying canvas._canvas,
> however the resulting clipping was so effective, that
> even the labels were clipped away.)

You need to modify attributes of the canvas where the symbols are
drawn to. This is quite simple:

    from pyx import *

    class clipsymbol(graph.style.symbol):

        def initdrawpoints(self, privatedata, sharedata, graph):
            privatedata.symbolcanvas = canvas.canvas([canvas.clip(path.rect_pt(graph.xpos_pt, graph.ypos_pt,
                                                                               graph.width_pt, graph.height_pt))])


    g = graph.graphxy(width=8)
    g.plot(graph.data.file("minimal.dat", x=1, y=2), [clipsymbol()])
    g.writeEPSfile("minimal")

In general I think such a clipping is a bad idea (feel free to argue
against this). So for the moment I would not like to add such a
feature to the symbol style directly (although we could do, but as
usual: "bad ideas won't be implemented" ... ;-)).


André

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