| PNG output quality degraded after RHEL6 patch [message #86947] |
Mon, 16 December 2013 08:38  |
![Paul Van Delst[1] is currently offline](theme/default/images/xoffline.png.pagespeed.ic.XRkd1fkXye.png "Paul Van Delst[1] is currently offline")
Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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Hello,
Disclaimer: I don't think this is an IDL issue, but a PNG (or other)
system library issue.
My linux (RHEL6) box got patched the other day and, since then, I've
noticed the quality/resolution of the PNG output (via the plot Save
method) has degraded.
An example of the plot.Save created graphics post-update is shown here:
http://ftp.emc.ncep.noaa.gov/jcsda/CRTM/.plots/test_png-save .png
A screen capture of the IDL plot window using ImageMagick's import
command is shown here:
http://ftp.emc.ncep.noaa.gov/jcsda/CRTM/.plots/test_png-scre encapture.png
(sorry - looks like newsreader split the URL)
As you can see from the latter plot the lines are much smoother. And the
latter plot quality is what I was getting with plot.Save in the past,
pre-RHEL6-patch.
I've toyed around with various anti-aliasing switches in IDL and what
not but the plot image quality in the generated file is still inferior.
So, I'm posting this message in case someone has managed to figure out
what happened to the various system libraries after the upgrade.
Anyone with more sysadmin-y nouse than me got any ideas? ChrisT et al?
cheers,
paulv
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| Re: PNG output quality degraded after RHEL6 patch [message #86951 is a reply to message #86947] |
Mon, 16 December 2013 17:08  |
Starbuck
Messages: 11
Registered: June 2012
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Junior Member |
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On Monday, December 16, 2013 9:38:39 AM UTC-7, Paul van Delst wrote:
> Hello,
>
>
>
> Disclaimer: I don't think this is an IDL issue, but a PNG (or other)
>
> system library issue.
>
>
>
> My linux (RHEL6) box got patched the other day and, since then, I've
>
> noticed the quality/resolution of the PNG output (via the plot Save
>
> method) has degraded.
>
>
>
> An example of the plot.Save created graphics post-update is shown here:
>
> http://ftp.emc.ncep.noaa.gov/jcsda/CRTM/.plots/test_png-save .png
>
>
>
> A screen capture of the IDL plot window using ImageMagick's import
>
> command is shown here:
>
> http://ftp.emc.ncep.noaa.gov/jcsda/CRTM/.plots/test_png-scre encapture.png
>
> (sorry - looks like newsreader split the URL)
>
>
>
> As you can see from the latter plot the lines are much smoother. And the
>
> latter plot quality is what I was getting with plot.Save in the past,
>
> pre-RHEL6-patch.
>
>
>
> I've toyed around with various anti-aliasing switches in IDL and what
>
> not but the plot image quality in the generated file is still inferior.
>
>
>
> So, I'm posting this message in case someone has managed to figure out
>
> what happened to the various system libraries after the upgrade.
>
>
>
> Anyone with more sysadmin-y nouse than me got any ideas? ChrisT et al?
>
>
>
> cheers,
>
>
>
> paulv
The suggestions below don't quite fit with the information you provided (since it doesn't sound like you changed the IDL version), but I figured I would throw it out there just in case.
What version of IDL are you using? If you are using IDL 8.2.3, make sure you have installed the patches for this version. The plots might be saved wrong if the 2nd patch is not installed. Do you have any other versions of IDL 8 installed on your system (such as IDL 8.1)? If you do, could you try using a different version to produce your plot and see if the same issue occurs?
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| Re: PNG output quality degraded after RHEL6 patch [message #86961 is a reply to message #86951] |
Tue, 17 December 2013 07:22 |
Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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On 12/16/13 20:08, Starbuck wrote:
> On Monday, December 16, 2013 9:38:39 AM UTC-7, Paul van Delst wrote:
>> Hello,
[description of plot differences elided]
>
> The suggestions below don't quite fit with the information you
> provided (since it doesn't sound like you changed the IDL version),
> but I figured I would throw it out there just in case.
>
> What version of IDL are you using? If you are using IDL 8.2.3, make
> sure you have installed the patches for this version. The plots
> might be saved wrong if the 2nd patch is not installed. Do you have
> any other versions of IDL 8 installed on your system (such as IDL
> 8.1)? If you do, could you try using a different version to produce
> your plot and see if the same issue occurs?
Oops, yeah, i forgot to put that info in:
IDL> print, !version
{ x86_64 linux unix linux 8.2.2 Jan 23 2013 64 64}
I'm preparing to ask for the v8.2.3 upgrade which may help.
The fact that on Monday IDL-generated PNGs looked o.k., and on Tuesday
arvo after the RHEL6 patch they didn't suggests to me it's a system-y thing.
The only other v8.2.2-IDL-on-RHEL6 guy here is out this week so I can't
test on his system. We do have IDL v8.1 on the supa-computer login nodes
(which are RHEL6 also) but the network lag (it's in Orlando) coupled
with the v8.1 function graphics rendering speed means its unusable for
FG output. It's DG or nothing on that system.
I will hunt around here for other local IDLers (most linux folk here are
matlab or python types, and everyone else is cursed with windows+putty :o)
cheers,
paulv
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