matplotlib-devel Mailing List for matplotlib

I started reading some of Adobe's documentation to find out if there's
something I've overlooked, and noticed that when I read the PDF
Reference in Preview.app, some example images have zoom-dependent
gridlines that look a lot like the output from pcolor. If even Adobe
creates PDF files that have this kind of artifacts, maybe it's a
rendering bug in the other viewers, or possibly the imaging model is
underspecified.

-- 
Jouni K. Seppänen
http://www.iki.fi/jks

Eric Firing <ef...@ha...> writes:

>> A different approach would be to output a raster image from pcolor and
>> render it with large pixels. I don't know how well that would work with
>> Agg, though.
>>
> I don't understand; wouldn't this wreck accuracy and defeat the purpose 
> of using pdf (scalability)?

I meant the same thing that happens when you do imshow(image,
interpolation='None') and save as pdf. Each rectangle becomes one pixel
in an embedded raster image object, which is rendered crisply by the
viewer.

Crisply, that is, if the viewer is Adobe Reader, ghostscript or xpdf. 
If you zoom in in Apple's Preview.app, the image looks blurry. But maybe
blurriness in one out of four renderers is better than white lines in
three out of four?

-- 
Jouni K. Seppänen
http://www.iki.fi/jks

On Sun, Apr 8, 2012 at 9:13 AM, Tony Yu <ts...@gm...> wrote:
>
>
> On Sat, Apr 7, 2012 at 8:40 PM, Benjamin Root <ben...@ou...> wrote:
>>
>>
>>
>> On Sat, Apr 7, 2012 at 1:34 PM, Tony Yu <ts...@gm...> wrote:
>>>
>>> I've been using the animations subpackage since it was introduced, but I
>>> only recently tried to save an animation using the `save` method.
>>> Unfortnately, I get a RuntimeError whenever I try to use it:
>>>
>>> ...
>>>   File
>>> "/Users/Tony/python/devel/mpl/lib/matplotlib/backends/backend_agg.py", line
>>> 4
>>> 52, in print_raw
>>>     renderer._renderer.write_rgba(filename_or_obj)
>>> RuntimeError: Error writing to file

It shouldn't be OS-dependent. In fact, as I keep being told "OSX is
practically unix!". (Sorry, I just get tired of being told that and
then having simple unix functionality fail spectacularly. I'm
better...I swear.)

Would it be possible to try the mencoder support instead? (If it's
possible to get that installed). Also, could you try the ffmpeg_file
"backend" which uses the temp files? It will be helpful to try to
narrow down whether the piping itself is making it angry or if
something is wrong with ffmpeg. You should just be able to do:

anim.save(..., writer='ffmpeg_file') or anim.save(..., writer='mencoder')

Also, can you run any/all of them with --verbose-debug? That might
help give a bit more error information.

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma