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color_quan & gif files [message #16489]

Thu, 29 July 1999 00:00

Simon Hall
Messages: 4
Registered: August 1998

Junior Member

Hi,

I'm producing a lot of images that will eventually end up on a web
page, so I'm generating .gif files. I'm also using a 24 bit display
so my code is something like this:

set_plot, 'win'
device, decomposed = 0

<do plot here>

tvlct, r, g, b, /get
write_gif, filename, color_quan(tvrd(/true), 1, r, g, b), r, g, b

(All this courtesy of dfanning.com, thanks David)

I do get valid gif files but color_quan seems to alter the colours a
little. Most noticably, the white background is now light grey
([248,248,248] rather than [255,255,255]). Not a big difference but
immediately obvious against a white background.

Has anyone else had this problem? Anyone know of a solution that
doesn't involve lightening all the images in photoshop... I don't want
to start poking around with quantization translation vectors if
someone else has already done it...

I'm using IDL 5.2 on NT4.

Once again, TIA

Simon Hall
Simon.Hall@atm.ch.cam.ac.uk

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[Message index]

		color_quan & gif files By: Simon Hall on Thu, 29 July 1999 00:00
		Re: color_quan & gif files By: davidf on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: Liam Gumley on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: davidf on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: Liam Gumley on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: Simon Hall on Fri, 30 July 1999 00:00

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