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Re: write_GIF, PNG: incomplete palette [message #33307 is a reply to message #33306]

Mon, 16 December 2002 10:36

wmconnolley
Messages: 106
Registered: November 2000

Senior Member

Streun Andreas <andreas.streun@psi.ch> wrote:
> when writing PNGs (or GIFs in IDL<5.4) I don't get
> the full 256 color palette but only something like
> 69 colors. As far as I know GIFs can have up to 256
> colors. Any idea what's the problem?

I write png's OK with a 256 colour table.

Are you sure you colour table *does* have 256 colours? If opened on an 8-bit
display with other apps running, you'll probably get fewer.

DF's pages will point you to the truth.

Try: print,!d.n_colors

If that doesn't give you 256 colours, you need a private colour map: try:

begin window,0,retain=2,col=256,/pix & wdelete,0

as your very first IDL command.

-W.

--
William M Connolley | wmc@bas.ac.uk | http://www.nerc-bas.ac.uk/icd/wmc/
Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself
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[Message index]

		Re: write_GIF, PNG: incomplete palette By: David Fanning on Mon, 16 December 2002 11:02
		Re: write_GIF, PNG: incomplete palette By: wmconnolley on Mon, 16 December 2002 10:36

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