| Re: Incomplete ouput PNG files. [message #78707 is a reply to message #78706] |
Wed, 14 December 2011 08:43   |
lecacheux.alain
Messages: 325
Registered: January 2008
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Senior Member |
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On 14 déc, 17:22, Mark Piper <mpi...@ittvis.com> wrote:
> On 12/14/2011 8:33 AM, alx wrote:
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>> I recently wanted to process a large number of data files in order to
>> produce the corresponding number of output image files, each in PNG
>> format. I choose to use NG graphics, since the sequence: "p =
>> image(some_data)& p.save('this_image.png')& p.close", appears pretty
>> well suitable for this purpose. No problem in coding the corresponding
>> IDL 8.1 project on my (Windows) workstation, and running it on a few
>> test files. Since the data files were stored on a remote (Windows)
>> server, I decided to run the project directly on the server, through a
>> remote connection from my workstation to the server, by using Terminal
>> Server. Still no problem: the job was running perfectly, and I could
>> remotely see each graphic window being open, then the corresponding
>> PNG file created, etc...
>> Now, to avoid any flashing on my screen, I just MINIMIZED the TS
>> window which was open on my workstation (no logout, no disconnect from
>> the remote server), the remote job continuing to run unattended.
>> Patatras ! From this point the PNG files were created but also harshly
>> truncated (basically reduced to a header and a void image).
>> I guess (but have not tested) that any other image file format would
>> have produced the same unsatisfying result.
>> A "true screen" seems then mandatory for having the "graphic.save"
>> function to work correctly: is it a bug of NG graphics or a feature?
>> Have some unix/linux people got same experience when using any X-
>> server in this way ?
>> alx.
>
> This is a slightly different workflow, but could you please try setting
> the BUFFER keyword in your call to IMAGE? E.g.,
>
> p = image(data, /buffer)
> p.save, 'this_image.png'
> p.close
>
> The graphic will be rendered in an offscreen buffer. I have a hunch that
> this may help, since this feels like a tricky (to me, at least) X server
> issue.
>
> mp- Masquer le texte des messages précédents -
>
> - Afficher le texte des messages précédents -
Setting the BUFFER keyword actually solved the problem. I now
understand what this keyword is useful to, a long lasting
interrogation for me! Thanks Mark.
alain.
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