| Re: Incomplete ouput PNG files. [message #78695 is a reply to message #78694] |
Thu, 15 December 2011 06:07   |
lecacheux.alain
Messages: 325
Registered: January 2008
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Senior Member |
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On 15 déc, 14:12, David Fanning <n...@dfanning.com> wrote:
> alx writes:
>> I could note that the "p.save"d PNG file size is depending on the
>> window size when using an open NG graphics window. I guess that the
>> saved graphic file will depend on the off-screen buffer size when
>> BUFFER keyword is used. But what is this size? I could not find the
>> answer in 8.1 documentation. Maybe larger that Coyote's one
>> (IDLgrBuffer has a maximum size of 82192x8192) ?
>
> I don' think an open window makes any difference
> in Function Graphics. In my tests, I got the same
> huge raster file output whether I created a normal
> sized window, or used the buffer. The only way to
> control this (confirmed by a re-read of one of
> Mark's articles on his blog) is to use the
> RESOLUTION keyword.
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.idlcoyote.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
I agree. RESOLUTION keyword is a solution, but the (true or implicit)
window size also plays some role. For an original image of size
2224x1124 and PNG output(from p=image(DIMENSIONS=...) &
p.save,BUFFER=...,RESOLUTION=...), I find:
BUFFER=1, RESOLUTION=96, DIMENSIONS=[800,600] -> FILE SIZE = 99 kB
BUFFER=1, RESOLUTION=300, DIMENSIONS=[800,600] -> FILE_SIZE = 290
kB
BUFFER=1, RESOLUTION=600, DIMENSIONS=[800,600] -> FILE SIZE = 488
kB
BUFFER=1, RESOLUTION=600, DIMENSIONS=[640,512] -> FILE SIZE = 423
kB
BUFFER=1, RESOLUTION=600, DIMENSIONS=[1024,768] -> FILE_SIZE = 602
kB
BUFFER=0, RESOLUTION=600, DIMENSIONS=[640,512] -> FILE SIZE = 423
kB
BUFFER=0, RESOLUTION=600, DIMENSIONS=[800,600] -> FILE SIZE = 408
kB
BUFFER=0, RESOLUTION=600, DIMENSIONS=[1024,768] -> FILE_SIZE = 602
kB
Note the (strange ?) difference between BUFFER=0 and 1 for
DIMENSIONS=[800,600]
alx.
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