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Re: TVRD to make GIF's with 24-bit color [message #17151] Wed, 15 September 1999 00:00
Joe Means is currently offline  Joe Means
Messages: 44
Registered: November 1996
Member
Thanks to David and Liam for your help with this. I'll be using your
ideas soon.
Joe Means

Joe Means wrote:

> Hi, I run WinNT on a PC and IDL 5.2.1. I use the statement:
> Device, Decomposed=0
> to use colortable mapping and produce some fine images in screen
> windows.
>
> Then I read them in amd make GIF's:
> imgA = TVRD()
> Write_Gif, 'image_a.gif', imgA
>
> These GIF's however, have mostly white colors. Any ideas?
> Joe Means
> Forest Science Dept,
> Oregon State univ.
Re: TVRD to make GIF's with 24-bit color [message #17163 is a reply to message #17151] Wed, 15 September 1999 00:00 Go to previous message
Liam Gumley is currently offline  Liam Gumley
Messages: 473
Registered: November 1994
Senior Member
Joe Means wrote:

Joe, just so we're clear: GIF files can only contain 8-bit images. If
you have displayed a 24-bit image and you wish to save it as a GIF, then
you must use TVRD(TRUE=1) and COLOR_QUAN to produce an 8-bit pseudocolor
image. If you wish to save a truecolor 24-bit image, then the JPEG and
TIFF formats are a good choice.

The SAVEIMAGE procedure mentioned in my previous post handles all of
this automatically. You just pick the output format, e.g.

IDL> saveimage, 'image.gif' ; GIF is the default
IDL> saveimage, 'image.jpg', /jpeg
IDL> saveimage, 'image.tif', /tiff

Cheers,
Liam.

--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley
Re: TVRD to make GIF's with 24-bit color [message #17164 is a reply to message #17151] Wed, 15 September 1999 00:00 Go to previous message
Liam Gumley is currently offline  Liam Gumley
Messages: 473
Registered: November 1994
Senior Member
Joe Means wrote:
> Hi, I run WinNT on a PC and IDL 5.2.1. I use the statement:
> Device, Decomposed=0
> to use colortable mapping and produce some fine images in screen
> windows.
>
> Then I read them in amd make GIF's:
> imgA = TVRD()
> Write_Gif, 'image_a.gif', imgA
>
> These GIF's however, have mostly white colors. Any ideas?

Joe,

You may wish to try my SAVEIMAGE procedure, available at
http://cimss.ssec.wisc.edu/~gumley/imagetools.html

To save the current window to a GIF, it's as simple as

IDL> saveimage, 'image.gif'

Cheers,
Liam.

--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley
Re: TVRD to make GIF's with 24-bit color [message #17166 is a reply to message #17151] Wed, 15 September 1999 00:00 Go to previous message
R.Bauer is currently offline  R.Bauer
Messages: 1424
Registered: November 1998
Senior Member
David Fanning wrote:

> Joe Means (means@fsl.orst.edu) writes:
>
>> Hi, I run WinNT on a PC and IDL 5.2.1. I use the statement:
>> Device, Decomposed=0
>> to use colortable mapping and produce some fine images in screen
>> windows.
>>
>> Then I read them in amd make GIF's:
>> imgA = TVRD()
>> Write_Gif, 'image_a.gif', imgA
>>
>> These GIF's however, have mostly white colors. Any ideas?
>
> Uh, read my web page? :-)
>
> http://www.dfanning.com/tips/strange_tvrd.html
>
> Cheers,
>
> David
>

You are very patient David, I believe thats's the most important
question behind the decomposed one.

Reimar
Re: TVRD to make GIF's with 24-bit color [message #17169 is a reply to message #17151] Tue, 14 September 1999 00:00 Go to previous message
davidf is currently offline  davidf
Messages: 2866
Registered: September 1996
Senior Member
Joe Means (means@fsl.orst.edu) writes:

> Hi, I run WinNT on a PC and IDL 5.2.1. I use the statement:
> Device, Decomposed=0
> to use colortable mapping and produce some fine images in screen
> windows.
>
> Then I read them in amd make GIF's:
> imgA = TVRD()
> Write_Gif, 'image_a.gif', imgA
>
> These GIF's however, have mostly white colors. Any ideas?

Uh, read my web page? :-)

http://www.dfanning.com/tips/strange_tvrd.html

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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