Re: [PyX-user] arrange key entries in rows and columns

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

Hi,

sorry for my late response (to this and the other mails I'll answer
today). I was in Vienna last week ... ;-)

On 05.04.05, Michael Strass wrote:
> So here is my problem: I want to plot 4 data sets in one graph also
> displaying a legend. So I use the class key for this purpose. It seems
> to me from reading the _reference_ manual that you can only arrange the
> key entries vertically that means in one column. Due the space left
> inside my graph it would be better to have two rows with two columns.
> How does it work, if at all?

The current graph key class does not allow you to do so. However you
can use your own graph key class. And its even not that complicated
since you can use the existing key each of the columns. Thats why we
do all this component architecture in the graph system! A modifed
version of the piaxis example would be:


    from math import pi
    from pyx import *
    from pyx.graph import axis

    class columnkey:

        def __init__(self, columns=2, dist=0.5*unit.v_cm, subkey=graph.key.key(),
                           border=0.3*unit.v_cm, keyattrs=None):
            self.columns = columns
            self.dist = dist
            self.subkey = subkey
            self.border = border
            self.keyattrs = keyattrs
            # copy some config features from the subkey
            # TODO: the positioning config should be moved into the graph
            self.hinside = subkey.hinside
            self.vinside = subkey.vinside
            self.hdist = subkey.hdist
            self.vdist = subkey.vdist
            self.hpos = subkey.hpos
            self.vpos = subkey.vpos

        def paint(self, plotitems):
            dist_pt = unit.topt(self.dist)
            c = canvas.canvas()
            plotitems = [plotitem for plotitem in plotitems if plotitem.gettitle() is not None]
            itemspercolumn = (len(plotitems) + self.columns - 1) // self.columns
            x_pt = 0
            while plotitems:
                subc = self.subkey.paint(plotitems[:itemspercolumn])
                c.insert(subc, [trafo.translate_pt(x_pt, 0)])
                x_pt += unit.topt(subc.bbox().width()) + dist_pt
                del plotitems[:itemspercolumn]
            if self.keyattrs is not None:
                newc = canvas.canvas()
                newc.draw(c.bbox().enlarged(self.border).path(), self.keyattrs)
                newc.insert(c)
                c = newc
            return c

    g = graph.graphxy(width=8, key=columnkey(),
            x=axis.linear(min=0, max=2*pi, title="$x$", divisor=pi,
                          texter=axis.texter.rational(suffix=r"\pi")),
            y=axis.linear(title="$y$"))

    g.plot(graph.data.function("y=sin(x)", title=r"$\sin(x)$"))
    g.plot(graph.data.function("y=cos(x)", title=r"$\cos(x)$"))
    g.plot(graph.data.function("y=sin(x+pi)", title=r"$\sin(x+\pi)$"))
    g.plot(graph.data.function("y=cos(x+pi)", title=r"$\cos(x+\pi)$"))

    g.finish()
    g.stroke(g.ygridpath(0))

    g.writeEPSfile("piaxis")

I would like to add this to the CVS for 0.8, but I don't really like
the name. Does anybody has a better name for columnkey?


André

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