[Matplotlib-users] SVG vs PNG

[k***@yahoo.com]

Hi, list:

In my quest to create MPL plots for insertion into Word documents, I tried post-script (doesn't work well - Word doesn't like the ps file created by MPL), pdf (can't create more then 8 plots per job and can not import into word), png (works but each plot needs to be magified manually before saving), and now I am playing around with the svg format. Word doesn't recognize the svg format but I can open the file in gimp, select the portion of the chart I need, and do cut-and-paste over to Word. I can do the same with png format too but svg format works better if I have to do cut and paste and scale.

My question is this:

While the svg files are much smaller then the cooresponding png file (yes, and scalable), I am surprised that the quality of the plot doesn't seem to be that much better (seem like about the same as compared to a corresponding png figure). I would have thought that they should (see for example: http://luxor-xul.sourceforge.net/talk/jug-nov-2002/slides.html#svg-1). Is this because MPL is not taking advantage of the capabilities offered by svg?

I know that not every one works with Word but for good or for bad, that's what I have to work with in oder to submit my paper for publishing. Surely many of you have come across this kind of chanllenge. What have you been doing for inserting MPL created charts into Word?

Thanks,

--
John Henry

[Alan G Isaac]

Post by k***@yahoo.com
png (works but each plot needs to be magified manually
before saving)

Use the figsize argument.

Cheers,
Alan Isaac

[Eric Firing]

Post by k***@yahoo.com
In my quest to create MPL plots for insertion into Word documents, I
tried post-script (doesn't work well - Word doesn't like the ps file
created by MPL), pdf (can't create more then 8 plots per job and can
not import into word), png (works but each plot needs to be magified
manually before saving), and now I am playing around with the svg
format. Word doesn't recognize the svg format but I can open the
file in gimp, select the portion of the chart I need, and do
cut-and-paste over to Word. I can do the same with png format too
but svg format works better if I have to do cut and paste and scale.

When you open the svg in gimp, it is being rendered as pixels; from that
point on, it is the same as if you had made a png at the same
resolution, except that there are subtle differences in positioning and
probably antialiasing between externally rendered svg and
mpl/agg-produced png.

Did you try eps rather than ps?

Eric

Post by k***@yahoo.com
While the svg files are much smaller then the cooresponding png file
(yes, and scalable), I am surprised that the quality of the plot
doesn't seem to be that much better (seem like about the same as
compared to a corresponding png figure). I would have thought that
http://luxor-xul.sourceforge.net/talk/jug-nov-2002/slides.html#svg-1).
Is this because MPL is not taking advantage of the capabilities
offered by svg?
I know that not every one works with Word but for good or for bad,
that's what I have to work with in oder to submit my paper for
publishing. Surely many of you have come across this kind of
chanllenge. What have you been doing for inserting MPL created
charts into Word?
Thanks,
-- John Henry
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[Zack]

Hi,

Post by Eric Firing
When you open the svg in gimp, it is being rendered as pixels; from that
point on, it is the same as if you had made a png at the same
resolution, except that there are subtle differences in positioning and
probably antialiasing between externally rendered svg and
mpl/agg-produced png.

Right. SVG in Matplotlib is NOT vector format and it has no sense to use it
instead of PNG or any others.

I'm just wondering, why it was implemented... if it implemented wrong.

[Jouni K. Seppänen]

Post by Zack

When you open the svg in gimp, it is being rendered as pixels; [...]

Right. SVG in Matplotlib is NOT vector format and it has no sense to
use it instead of PNG or any others.

No, the svg produced by matplotlib is a vector format. (Just look at a
matplotlib-generated svg file in a text editor.) When you open a svg
file in gimp, gimp converts it into pixels, because gimp only works
with pixel-based images.

I seem to recall that someone created an emf (enhanced metafile)
backend in matplotlib. Have you tried that?

[k***@yahoo.com]

Thanks everybody for the explanation of svg in Gimp. That makes sense. Is there any vector based program that does what Gimp does?

Post by Eric Firing
Did you try eps rather than ps?
Eric

Yes, I tried eps. Word won't recognize that neither.

As to the EMF format, I downloaded the package and attempted to apply the patch. Failed - probably because it's intended for 0.85 only. I am running 0.90 of MPL. Has anybody added EMF support to MPL 0.90 successfully?

Regards,



--
John Henry

[Fernando Perez]

Post by k***@yahoo.com
Thanks everybody for the explanation of svg in Gimp. That makes sense. Is there any vector based program that does what Gimp does?

Try inkscape. I've used it successfully for simple things, though
I've never tried to handle a MPL SVG file with it.

cheers,

f

[k***@yahoo.com]

Chris,

All I want is to:

a) Insert all of the plots I create with MPL onto a Word document.

As I said before, my version of Word does not recognize the EPS or PS format created by MPL. I am not blaiming MPL. I am just not willing to send Redmond money to see if their later version does the job properly. The version of Word I have does not import PDF files neither. Besides, the PDF backend of MPL fails when the total number of figures is more then 8.

b) Be able to cut and paste part of a MPL figure and insert that to Word. I can do it now via the Gimp path but as I explained previously, the quality is not the greatest. I'll look up the cookbook you cited and try that.

Thanks,

-----Original Message-----
Sent: Friday, May 11, 2007 11:10 AM
Subject: Re: [Matplotlib-users] SVG vs PNG

Post by k***@yahoo.com
Thanks everybody for the explanation of svg in Gimp. That makes
sense. Is there any vector based program that does what Gimp does?

By definition, No. GIMP is a raster editor, it is similar to other
raster editors, and fundamentally different than vector
graphics programs.
There is a little overlap, what do you want to do?
It sound like what you really need is a way to put MPL plots
in a Word
doc. Ideally, you'd use a vector format like EPS, because
that's exactly
what EPS is for. However, MS has never been good at supporting open
formats like that.
I'd try PDF. Recent versions of Word may do OK with that.
Otherwise, you're back to a lowest common denominator. I've ended up
just using PNG. If you set the ppi right, it works just fine.
See this

http://www.scipy.org/Cookbook/Matplotlib/AdjustingImageSize

-Chris
--
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R [phone] voice
7600 Sand Point Way NE [phone] fax
Seattle, WA 98115 [phone] main reception

***@noaa.gov


--
John Henry

[Alan G Isaac]

All I want is to: a) Insert all of the plots I create with
MPL onto a Word document.

This part should be achievable with PNG.
Just set the figsize.
I have not had problems...

b) Be able to cut and paste part of a MPL figure and
insert that to Word

You can select part of a PDF for copying to the clipboard
in Acrobat.

fwiw,
Alan Isaac

[k***@yahoo.com]

Post by Alan G Isaac

All I want is to: a) Insert all of the plots I create with
MPL onto a Word document.

This part should be achievable with PNG.
Just set the figsize.
I have not had problems...

Correct. I am doing that right now. However, because it's not vector based, if I start chaning the figure size, the quality suffers.

Post by Alan G Isaac

b) Be able to cut and paste part of a MPL figure and
insert that to Word

You can select part of a PDF for copying to the clipboard
in Acrobat.

Been there, done that. Doesn't work. It selects the titles, and anotations. Doesn't select the graphs.

Post by Alan G Isaac
fwiw,
Alan Isaac

--
John Henry

[A***@gtri.gatech.edu]

Post by k***@yahoo.com

Post by Alan G Isaac

All I want is to: a) Insert all of the plots I create with MPL onto
a Word document.

This part should be achievable with PNG.
Just set the figsize.
I have not had problems...

Correct. I am doing that right now. However, because it's not
vector based, if I start chaning the figure size, the quality suffers.

Post by Alan G Isaac

b) Be able to cut and paste part of a MPL figure and insert that to
Word

You can select part of a PDF for copying to the clipboard in Acrobat.

Been there, done that. Doesn't work. It selects the titles,
and anotations. Doesn't select the graphs.

Perhaps you could use OpenOffice Draw as described in this url:

http://wolfey.sillydog.org/blog/2006/09/20/vector-image-file-conversion-
svg-wmf/

It's a shame that it takes such a workaround.

[John Hunter]

Post by k***@yahoo.com
While the svg files are much smaller then the cooresponding png file (yes, and
scalable), I am surprised that the quality of the plot doesn't seem to be that much
better (seem like about the same as compared to a corresponding png figure).
http://luxor-xul.sourceforge.net/talk/jug-nov-2002/slides.html#svg-1).
Is this because MPL is not taking advantage of the capabilities offered by svg?

The quality of the svg plot depends in large plot on the svg renderer
-- perhaps word doesn't do a good job rendering SVG? The matplotlib
PNG files look good because agg is a good rendering engine.

JDH

[k***@yahoo.com]

Bingo! My prayer appears to have been answered.

inkscape has no trouble reading the .svg files created by MPL, and Word has no trouble reading the .eps files created by inkscape. So, at least I can use it to preserve the vectors. Too bad inkscape doesn't read .eps directly (complaining...complaining....) :=)

inkscape treats everything as objects and allows you to ungroup the plots into elements and then you can play with each of the elements individually. When I am done, I can then insert into Word. Too bad it doesn't allow me to paste the objects directly over to Windows but I am not complaining.

Thanks, Fernando.

-----Original Message-----
Sent: Friday, May 11, 2007 11:05 AM
Subject: Re: [Matplotlib-users] SVG vs PNG

Post by k***@yahoo.com
Thanks everybody for the explanation of svg in Gimp. That makes
sense. Is there any vector based program that does what Gimp does?

Try inkscape. I've used it successfully for simple things,
though I've never tried to handle a MPL SVG file with it.
cheers,
f

--
John Henry

[Christopher Barker]

Post by k***@yahoo.com
inkscape has no trouble reading the .svg files created by MPL, and
Word has no trouble reading the .eps files created by inkscape.

hmm. I wonder what it is about MPL's .eps files that Word doesn't like.


Bug in MPL or Word??

-Chris
--
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R [phone] voice
7600 Sand Point Way NE [phone] fax
Seattle, WA 98115 [phone] main reception

***@noaa.gov

[Fernando Perez]

Post by k***@yahoo.com
Bingo! My prayer appears to have been answered.
inkscape has no trouble reading the .svg files created by MPL, and Word has no trouble reading the .eps files created by inkscape. So, at least I can use it to preserve the vectors. Too bad inkscape doesn't read .eps directly (complaining...complaining....) :=)

Did you install pstoedit? If you do, you'll see that inkscape will
then be able to load .eps/.ps files in a fully editable format. I've
used it to fix decade-old plots for which the only thing around was
the eps file.

Post by k***@yahoo.com
Thanks, Fernando.

Glad it helped.

Cheers,

f

[Steve Schmerler]

Post by Fernando Perez
Did you install pstoedit? If you do, you'll see that inkscape will
then be able to load .eps/.ps files in a fully editable format. I've
used it to fix decade-old plots for which the only thing around was
the eps file.

I tried to export an .svg from MPL (0.90.0rev3131) with
rcParams['text.usetex']=True and got a NotImplementedError (same for the pdf backend
with usetex, see attached log). I was wondering: Is it (technically) possible to have
.svg export capabilities with usetex-support and if so, has there been no need for
this feature so far (not that I need it urgently, just curious..)?

Anyway, to work with MPL-images (.ps/.eps) in Inkscape, I installed pstoedit but
loading these files doesn't work (seems not to recognize them as images).
Sorry if I'm driving the Inkscape-stuff a bit OT here, but:
What version of Inkscape & friends are you using? I'm using pstoedit 3.44, Inkscape
0.44.1. The Latex-formula-feature of Inkscape is also not working and the error seems
related to pstoedit. Maybe someone had similar experiences ...

Thanks for any hint!

[Jouni K. Seppänen]

I was wondering: Is it (technically) possible to have .svg export
capabilities with usetex-support and if so, has there been no need
for this feature so far

The usetex feature is implemented for the Agg backend (i.e., png
output) using dvipng, and for the PostScript backend using (I think)
dvips with psfrag, and neither of these is easily generalizable to
work with svg or pdf. However, some time ago I committed the
beginnings of a dvi parser and a little support code in the pdf
backend, enough to get a small demo almost working:

http://article.gmane.org/gmane.comp.python.matplotlib.devel/2687

I have no idea how difficult it would be to get this working in the
svg backend, but in the pdf backend the biggest hurdle is probably in
generalizing the current font support so that the TeX fonts can be
embedded.

[Jochen Küpper]

for the PostScript backend using (I think) dvips with psfrag, and
neither of these is easily generalizable to work with svg or pdf.

What's the problem of using dvi2pdf, dvipdfm, dvipdfmx, or soemthing
like that for PDF?
Looks quite similar to the dvips route for Postscript to me?

Greetings,
Jochen

[Jouni K. Seppänen]

Post by Jochen Küpper

for the PostScript backend using (I think) dvips with psfrag, and
neither of these is easily generalizable to work with svg or pdf.

What's the problem of using dvi2pdf, dvipdfm, dvipdfmx, or soemthing
like that for PDF?
Looks quite similar to the dvips route for Postscript to me?

The dvips route is not so simple. First matplotlib creates the
PostScript file with all text strings replaced by tags, and this is
fed to LaTeX using \includegraphics. The psfrag package replaces the
tags with LaTeX constructs, and then the dvi file is converted using
dvips into the final postscript file. There is no equivalent to psfrag
that works with pdf (at least none that I know of).

Probably you could create a pdf file without any texts and input that
in your LaTeX file, and then -- with sufficient LaTeX-fu -- render the
text strings at the correct positions, and run the LaTeX file through
pdflatex, because pdftex includes a pdf parser so that you can do
\includegraphics{foo.pdf}. So in that sense it may be generalizable,
but it won't be a direct port of the ps backend.

[Christopher Barker]

Post by Jouni K. Seppänen
However, some time ago I committed the
beginnings of a dvi parser and a little support code in the pdf
http://article.gmane.org/gmane.comp.python.matplotlib.devel/2687
I have no idea how difficult it would be to get this working

I have no idea either, but thanks for getting this started -- it is
absolutely the way to go -- that's the whole point of DVI (DeVice
Independent)

-CHB
--
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R [phone] voice
7600 Sand Point Way NE [phone] fax
Seattle, WA 98115 [phone] main reception

***@noaa.gov

[Fernando Perez]

Post by Steve Schmerler

Post by Fernando Perez
Did you install pstoedit? If you do, you'll see that inkscape will
then be able to load .eps/.ps files in a fully editable format. I've
used it to fix decade-old plots for which the only thing around was
the eps file.

I tried to export an .svg from MPL (0.90.0rev3131) with
rcParams['text.usetex']=True and got a NotImplementedError (same for the pdf backend
with usetex, see attached log). I was wondering: Is it (technically) possible to have
.svg export capabilities with usetex-support and if so, has there been no need for
this feature so far (not that I need it urgently, just curious..)?

There's actually a real MPL bug in there (not just the
NotImplementedError) but I'll report it separately in a minute.

Post by Steve Schmerler
Anyway, to work with MPL-images (.ps/.eps) in Inkscape, I installed pstoedit but
loading these files doesn't work (seems not to recognize them as images).
What version of Inkscape & friends are you using? I'm using pstoedit 3.44, Inkscape
0.44.1. The Latex-formula-feature of Inkscape is also not working and the error seems
related to pstoedit. Maybe someone had similar experiences ...
Thanks for any hint!

Well, unfortunately it seems that inkscape is crashing python
itself... I made a trivial .eps in mpl with:

In [1]: plot(range(10))
Out[1]: [<matplotlib.lines.Line2D instance at 0x8f45a8c>]

In [2]: title(r'Some \LaTeX $\int_0^\infty f(\gamma) d\gamma = 1$')
Out[2]: <matplotlib.text.Text instance at 0x8f4590c>

In [3]: savefig('foo.eps')


and when I tried to load it into inkscape, I got this very nasty traceback:

*** glibc detected *** /usr/bin/python: free(): invalid pointer: 0x4081e4e0 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6[0x400ee7cd]
/lib/tls/i686/cmov/libc.so.6(cfree+0x90)[0x400f1e30]
/usr/lib/skencil/Sketch/../Lib/streamfilter.so[0x404e7ce5]
/usr/lib/skencil/Sketch/../Lib/streamfilter.so[0x404e7cd2]
/usr/bin/python[0x8110e6a]
/usr/bin/python(PyEval_EvalCodeEx+0x313)[0x80c9903]

etc.

At this point, this is really becoming OT for the mpl list, so I'll
stop. But if anyone has the time, it might be worth sending this
example to the inkscape list so they work on it and hopefully fix it.

Cheers,

f

[k***@yahoo.com]

Yes, that's what I've been forced to do. The problem with that is that it forces you to fix the size of the figures in your paper. When I reformat things around in subsequent revisions, I have to go back and recreate the figures - if the spacing changes. I would much rather retaining the ability to rescale in Word. Yes, I know that it does change the font size.

But as I indicated in my other message, I think Inkscape is the solution. I am still playing around with it and see if that really does it but it looks real promising.

Regards,



-----Original Message-----
From: David Huard
[mailto:***@gmail.com]
Sent: Friday, May 11, 2007 12:06
PM
To: kc106_2005-***@yahoo.com
Subject: Re:
[Matplotlib-users] SVG vs PNG


My advice would be to define
the size you'll want the figure to be on paper once printed, and set the
resolution to 300 dpi (for paper) or 100 (for
screen):
e.g.

fig.savefig(figsize=(8,8), dpi=300)

Rescaling the
figure is generally a bad idea for inclusion in a paper since it changes the
font size as well. To get a nice output, you try to keep the same font size for
both paper and figures, and the simplest was to do this is by avoiding
rescaling.

Cheers,

David




2007/5/11, kc106_2005-***@yahoo.com
<

Post by Alan G Isaac

All I want is to: a) Insert all of the plots I

create with

Post by Alan G Isaac

MPL onto a Word document.

This part

should be achievable with PNG.

Post by Alan G Isaac
Just set the figsize.
I have not

had problems...
Correct. I am doing that right now. However,
because it's not vector based, if I start chaning the figure size, the quality
suffers.

Post by Alan G Isaac

b) Be able to cut and paste part of a MPL figure

and

Post by Alan G Isaac

insert that to Word

You can select part of a

PDF for copying to the clipboard

Post by Alan G Isaac
in Acrobat.

Been there,
done that. Doesn't work. It selects the titles, and anotations. Doesn't
select the graphs.

Post by Alan G Isaac
fwiw,
Alan

Isaac
--
John
Henry



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--
John Henry

[k***@yahoo.com]

Post by Christopher Barker

Post by k***@yahoo.com
inkscape has no trouble reading the .svg files created by MPL, and
Word has no trouble reading the .eps files created by inkscape.

hmm. I wonder what it is about MPL's .eps files that Word
doesn't like.
Bug in MPL or Word??

Most likely Word. It's very picky. I have .eps files created by other programs where Word would simply tell you that it's not a supported format. Doesn't say why.



--
John Henry

[k***@yahoo.com]

Actually, Gimp is the problem. It's obvious they don't have a very good rendering engine. The plots looks very good under Inkscape.

Post by John Hunter
The quality of the svg plot depends in large plot on the svg renderer
-- perhaps word doesn't do a good job rendering SVG? The
matplotlib PNG files look good because agg is a good rendering engine.
JDH

--
John Henry

[Matt Newville]

All I want is to: a) Insert all of the plots I create with MPL onto a Word document.

If you're fortunate enough to be using the wx backend, there is a
Copy_to_Clipboard() method which works great: In a wx App, Ctrl-C can
easily be bound to copy the figure to the clipboard, then paste it
into apps such as Word. I tend to find better results from saving a
higher-resolution PNG and inserting that into documents, but this
copy-and-paste works great for quick prints (whereas printing directly
from a wxApp seems to be very fragile and change with every wxPython
release)

I think pylab may not give you access to the Copy_to_Clipboard() method.

--Matt Newville

[k***@yahoo.com]

Not exactly OT.

I would not recommend using .eps format in order to
export MPL graphs for Inkscape. I've been playing
around with Inkscape for a few days now and I've been
using .svg exclusively and don't have any problem.

As I said before, I like the fact that once I am
inside Inscape, I can do an ungroup of the graph, and
work with all of the plotting elements individually.
In fact, I just discover a nice way to "cut and paste"
a particular subplot over to PowerPoint. This gives
me very high quality graphs in Power Point (I can
scale all I want). No more fuzzy, ugly-looking Power
Point charts.

Here's how:

a) Create MPL plots in .svg format
b)

[k***@yahoo.com]

This SVG format gets better everyday.

For those of you unfortunate enough not to have the
choice of freedom from the M$ Monopoly, I discovered
that Visio supports SVG file directly. In fact, the
rendering is better then Inscape and get this: you can
copy and paste *directly* over to PowerPoint and Word
and you can even embed it as a Visio object. The
quality is superb!

Even the browser can read SVG file (somewhat - the
quality isn't very good).

-----Original Message-----
From: Derek Hohls
Sent: Tuesday, May 15, 2007 12:19 AM
Subject: Re: [Matplotlib-users] SVG vs PNG
For those of you fortunate enough to have the
choice be free from the M$ Monopoly, you can
use the Open Office Impress package to do
something similar to the steps below.
However, if you want to work directly with SVG
files, then you should install the SVG "import

http://www.ipd.uka.de/~hauma/svg-import/

(Installation and use are described very clearly).
If you have saved an SVG file from MPL, you
can now open it in Open Office Draw, ungroup
it (you will need to repeat this command a
number of times) and edit the elements.
Save the file as an Open Office drawing
(.odg) for use in other Open Office applications.
One strange thing I encountered was that the
default background for fonts was blue?
This seems to be a problem with the
import filter, and has been reported on the

http://wiki.services.openoffice.org/wiki/SVG_User_Experiences#

Blue_background_for_all_text_elements
left-click to select a text element, then
right-click and choosing Edit Style... and
then select White or None from the Area menu.
*** As a footnote, I see that an integrated
SVG filter, designed to be shipped as part of
Open Office, is scheduled to be developed as

http://wiki.services.openoffice.org/wiki/Summer_of_Code_2007/p

roposals#Draw.2FImpress:_SVG_Import_Filter

01:08 AM >>>

Not exactly OT.
I would not recommend using .eps format in order to
export MPL graphs for Inkscape. I've been playing
around with Inkscape for a few days now and I've

been

using .svg exclusively and don't have any problem.
As I said before, I like the fact that once I am
inside Inscape, I can do an ungroup of the graph,

and

work with all of the plotting elements individually.
In fact, I just discover a nice way to "cut and

paste"

a particular subplot over to PowerPoint. This gives
me very high quality graphs in Power Point (I can
scale all I want). No more fuzzy, ugly-looking

Power

Point charts.
a) Create MPL plots in .svg format
b)