matplotlib-users Mailing List for matplotlib

John Hunter wrote:
[snip]
>Here is a sample implementation
>
>from matplotlib.matlab import *
>def segplot(x, y, fmt, maxdelta, **kwargs):
> """
> Plot x versus y, breaking the plot at any point where x[i] -
> x[i-1] > maxdelta. kwargs are passed on to plot
> """
> x = asarray(x)
> y = asarray(y)
> d = diff(x)
> lines = []
> ind = nonzero(greater(d, maxdelta))
> ind = ind+1
> if not len(ind):
> lines.extend( plot(x,y,fmt,**kwargs) ) 
> else:
> allind = [0]
> allind.extend(ind)
> allind.append(len(x))
> for i1,i2 in zip(allind[:-1], allind[1:]):
> lines.extend( plot(x[i1:i2], y[i1:i2], fmt, **kwargs) )
> return lines
>
>t = [0,1,2,3,4,5,105,106,107,187, 200, 212, 300, 320]
>s = [1,4,5,3,9,11,-5,-8,3,12, 15, 12, -1, 3]
>segplot(t, s, 'b-o', 40, antialiased=False)
>grid(True)
>show()
>
>I'm inclined not to make this part of plot, since plot processes a
>variable number of arguments it makes it a little difficult.
>Certainly doable, but I'm hesitant to put too much on plot because it
>might become unwieldy. But a new function, like segment plot, would
>be easy enough to include.
>
>Any suggestions for a name, or additional functionality?
> 
>
Thanks for the quick solution. I think the name is just fine.
Best,
-- 
Peter Groszkowski Gemini Observatory
Tel: +1 808 974-2509 670 N. A'ohoku Place
Fax: +1 808 935-9235 Hilo, Hawai'i 96720, USA

>>>>> "Flavio" == Flavio Codeco Coelho <fcc...@fi...> writes:
 Flavio> Sorry, I meant portable in terms of other hardware
 Flavio> platforms that run Linux but not X, embedded systems for
 Flavio> instance. The situation I had in mind was to run
 Flavio> matplotlib in a linux PDA (which are becoming more and
 Flavio> more popular). The Sharp Zaurus, for instance, runs a kind
 Flavio> of Qt, for which there is no matplotlib backend. All linux
 Flavio> systems, big and small, have console interfaces. Although
 Flavio> I think it may be possible to install GTK or Wx on a PDA
 Flavio> like the Zaurus, It would not be the the best way to go
 Flavio> due to limitations of memory and other resources. A
 Flavio> console Backend wold not only be lighter and faster, but
 Flavio> could go wherever python can go, independently of heavy
 Flavio> GUI systems.
 Flavio> Another solution would be a backend for Qt embedded
 Flavio> library, but it does need framebuffer as far as I know...
 Flavio> And it's not only PDAs, matplotlib could run on
 Flavio> cellphones, set-top boxes, industrial controlers, etc.
 Flavio> Again it's just a thought, I am a big fan of Links... ;)
I'm not familiar with Links....
As far as embedded devices, one possibility is the paint / libart
backend. libart was designed to be small and had the embedded market
in mind, if I recall correctly. A quick google search appears to
indicate that libart is ported to Zaurus. Also, if the embedded
device has a recent cxx compiler, it should be able to compile agg.
The reason I mention this is that it is fairly straightforward to mix
and match an image backend (gd, libart/paint, agg) with a gui toolkit.
Witness GTKAgg, TkAgg, WxAgg (forthcoming) and GTKGD. So it might be
easier (and more general purpose) to implement QtPaint or QtAgg than
it would be to implement a libsvga backend. One thing I've
encountered with the variety of image backends (ps, paint, agg and gd)
is that it is very difficult to support all the features you want on
all the backends.
 ps - no alpha channel or antialised drawing
 gd - no alpha and a color allocation bug; only 256 colors
 libart - a pesky clipping bug that the libart author has been
 unresponsive on; no subpixel rendering. no freetype2 support in
 paint (yet)
 agg - no significant 2D limitations.
 
The same can be said for the native GUI drawing backends GTK and WX.
My push to encourage people to use one of the agg backends for GUI or
PNG is to get around the maintenance hassles associated with trying to
support all these features across many backends. So my preference
would be to 1) implement QTAgg and 2) try and port agg to the embedded
device. The latter may not satisfy the size constraints for embedded
devices (_backend_agg.so is around 600K on my box).
But if you don't think these arguments are persuasive let me know.
Especially if you would be willing to implement (and maintain) a
console backend!
JDH

>>>>> "Flavio" == Flavio Codeco Coelho <fcc...@fi...> writes:
 Flavio> Hi John, Have you thought about writing a backend for
 Flavio> matplotlib that would display the plot in the console (no
 Flavio> X)? It could use the linux framebuffer or the SVGALib,
 Flavio> just like Links.
 Flavio> It would make it much more portable.
What do you mean by portable? Both the linux framebuffer and svgalib
are, as far as I know, linux only.
JDH

If you're not intereste in creating a text file,
The best way to go, is with pickle.dump and pickle.load
Check the python docs about them.
cheers,
Fl=E1vio
On Thu, 2004年04月08日 at 17:38, Randy Heiland wrote:
> What's the easiest way to write a Numeric array to a file?
> Thanks! --Randy
>=20
>=20
>=20
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