gnuplot-py-users

[Gnuplot-py-users] getting output as gif / jpeg / png?

[David C. <da...@ne...>]

Hello,

I have just come across gnuplot, and am very pleased to discover the python
interface.  Everything appears to be set up here correctly... the demo
charts are outstanding.

My question: how do I get the output of gnuplot to go into a gif, png or
jpeg file?  I believe I have compiled and installed all of the correct
components to make this possible... but I just don't know where to throw the
switch.  Can someone give me a quick pointer?

Thanks,
David.

Re: [Gnuplot-py-users] getting output as gif / jpeg / png?

[David C. <da...@ne...>]

On 1/10/03 8:32 AM, "David Casti" <da...@ne...> wrote:

> My question: how do I get the output of gnuplot to go into a gif, png or
> jpeg file?  I believe I have compiled and installed all of the correct
> components to make this possible... but I just don't know where to throw the
> switch.  Can someone give me a quick pointer?

I asked too soon... turns out this is not hard at all --

import Gnuplot, Gnuplot.funcutils
g = Gnuplot.Gnuplot( debug=1 )
g('set term png')
g('set output "/tmp/david.png"')
g.plot( [ [0, 1], [1, 2], [2, 3], [3, 4] ] )

-- and observe the output file in /tmp/david.png.

It appears that jpeg and gif support is going to be trickier... because "set
terminal" at the gnuplot command prompt does not show those to be available
terminal types.  Once I figure out how to make them available, the way to
use them in gnuplot.py is clear.

I hope this post helps a future gnuplot.py user!  :)
David.

Re: [Gnuplot-py-users] getting output as gif / jpeg / png?

[<kai...@t-...>]

David,

Thanks for your email.  Obviously you figured out one way to print to a 
file.

I was working on generic support for gnuplot terminals and the code is 
checked into CVS.  If you are willing to install Gnuplot.py from CVS you 
can try it out.  I've defined a mechanism in termdefs.py for defining 
terminal options, and I've typed the list of options for a few terminal 
types into that file (including png).  It would be easy for you to add 
the information about other terminal types that you want to use, and 
then the Gnuplot.hardcopy() method will be able to work the them. 
 Unfortunately the only documentation is in the source file, which is 
one reason that I haven't released a version including this new code :-( 
 The other, main reason is that I haven't had time to work on Gnuplot.py 
in quite a while. :-( :-(

You might run into the famous "temporary-file deletion" problem if you 
try to use your script in an automated environment.  See the archives of 
this newsgroup and FAQS.txt in the CVS repository of Gnuplot.py for more 
information.

Regarding the jpeg and gif support: jpeg should work (afaik) though 
since it is lossy it is not ideal for output such as that produced by 
gnuplot.  (You will especially notice that the large white background 
regions are not uniform.)  PNG is the recommended output format if it 
can be used by the rest of your tools.  Jpeg support is compiled into 
the gnuplot packaged with RedHat Linux but it is possible that you have 
to recompile gnuplot to enable support for it.

I don't believe that gnuplot supports GIF anymore because GIF is a 
proprietary format and to write GIF files requires paying a license fee 
to somebody.  But see the gnuplot web site or user groups for the latest 
information on that topic.

Yours,
Michael

David Casti wrote:

>On 1/10/03 8:32 AM, "David Casti" <da...@ne...> wrote:
>
>>My question: how do I get the output of gnuplot to go into a gif, png or
>>jpeg file?  I believe I have compiled and installed all of the correct
>>components to make this possible... but I just don't know where to throw the
>>switch.  Can someone give me a quick pointer?
>>    
>>
>
>I asked too soon... turns out this is not hard at all --
>
>import Gnuplot, Gnuplot.funcutils
>g = Gnuplot.Gnuplot( debug=1 )
>g('set term png')
>g('set output "/tmp/david.png"')
>g.plot( [ [0, 1], [1, 2], [2, 3], [3, 4] ] )
>  
>

-- 
Michael Haggerty
mh...@al...