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Re: LZW in IDL [message #39721 is a reply to message #39720]

Wed, 09 June 2004 21:52

andrew.cool
Messages: 47
Registered: July 2003

Member

Jonathan Joseph <jj21@cornell.edu> wrote in message news:<ca7qcv$8bl$1@news01.cit.cornell.edu>...
> Is there a way to query whether or not you have permission to write an
> LZW compressed tiff file?
>
> I just found out that we actually do have the LZW licensing string in
> the license.dat file. Unfortunately, It seems as though the number of
> allowable LZW licenses is 1, while the number of allowable IDL licenses
> is 8 - so if someone else has started IDL before you, they have the one
> and only LZW license. I hope this was just a glitch in the creation of
> the license.dat file. Another multi-user license we have seems to have
> the same number of LZW licenses as IDL licenses.
>
> Regardless of whether I get our licensing working correctly, I would
> like to be able to write the code so that it uses LZW if availalbe and
> either no compression or packbits otherwise. Is there any way to query
> whether the write_tiff command with compress=1 will work before calling
> it? Currently, if LZW licensing is not available, the program will halt
> at the write_tiff call (despite something I read on an RSI web page
> which claimed that it would default to packbits).
>
> For example, if I send the code to collaborators, I want it to not crash
> if they don't have LZW licensing. Even when the Unysis patents expire,
> It will take some IDL maintenamce (at least a new license string, if not
> a new version of IDL) to be able to use the functionality again.
>
> Thanks.
>
> -Jonathan

Jonathon,

Try issuing the command Help,/DLM,OUT=a
This will return a list of all the DLMs that IDL knows about, even if
they haven't been loaded in that session yet.

IDL> help,/dlm,out=a
IDL> gif=where(strmid(a,0,6) EQ '** GIF')
IDL> print,a(gif)
** GIF - IDL GIF support (not loaded)

If GIF reurns as -1, then you ain't got GIF available

Cheers,

Andrew
DSTO, Adelaide, South Australia

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[Message index]

		Re: LZW in IDL By: Haje Korth on Thu, 10 June 2004 06:04
		Re: LZW in IDL By: Haje Korth on Thu, 10 June 2004 06:02
		Re: LZW in IDL By: Mark Hadfield on Wed, 09 June 2004 23:17
		Re: LZW in IDL By: andrew.cool on Wed, 09 June 2004 21:52
		Re: LZW in IDL By: Mark Hadfield on Wed, 09 June 2004 16:52
		Re: LZW in IDL By: David Fanning on Wed, 09 June 2004 13:11
		Re: LZW in IDL By: Jonathan Joseph on Wed, 09 June 2004 13:01
		Re: LZW in IDL By: Haje Korth on Wed, 09 June 2004 11:15

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