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Re: Color table [message #58176 is a reply to message #8601]

Mon, 21 January 2008 07:09

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

WRC2008@gmail.com writes:

> me....again...
>
> Everything works out fine for the blue-white-red, even the background
> color and axis colors, as the colortable.
>
> BUT, I am also working with the blue-red color table, defined as
> follows:
>
>
> steps = 256
> scaleFactor = FINDGEN(steps) / (steps - 1)
> ;color scheme by Fanning to go from blue to red
> tvlct,red,green,blue,/get
> ;Red vector: 0 -> 255
> red = 0 + (255 - 0) * scaleFactor
> ; Green vector: 0 -> 0
> green= REPLICATE(0, steps)
> ; Blue vector: 255 -> 0
> blue = 255 + (0 - 255) * scaleFactor
> TVLCT, red, green, blue
> DEVICE, RETAIN=2, DECOMPOSED=0
> Window, Xsize=steps,Ysize=40, Title='Color Table'
> TV, bindgen(steps) # replicate(1B,40)
>
>
>
> This is also working, fine, but again, my background went to blue, as
> do all the symbols, axes and text in the plot. I would like to change
> background (outside of the plot, but in the window) into white, and
> the rest in black. How can this be done? Just changing to another
> colorvalue e.g. 0 to 255, of course doesn't change with this blue-red
> color table...

The best way to avoid changing the background and foreground
colors is to, well, avoid changing them. :-)

They are located at the top and the bottom of the color table.
(Another good reason not to change them is that if you don't your
PostScript output has a fairly good chance of looking like your
display output.)

Try something like this:

steps = 254
scaleFactor = FINDGEN(steps) / (steps - 1)
;color scheme by Fanning to go from blue to red
tvlct,red,green,blue,/get
;Red vector: 0 -> 255
red = 0 + (255 - 0) * scaleFactor
; Green vector: 0 -> 0
green= REPLICATE(0, steps)
; Blue vector: 255 -> 0
blue = 255 + (0 - 255) * scaleFactor
Loadct, 0, /Silent
TVLCT, red, green, blue, 1
DEVICE, RETAIN=2, DECOMPOSED=0
Window, Xsize=steps,Ysize=40, Title='Color Table'
TV, BytScl(bindgen(steps) # replicate(1B,40), Top=253) + 1B
window, 1
plot, findgen(11)

If you have the CINDEX program, you can have a look at
how your color table looks:

IDL> CIndex

You can find the program here:

http://www.dfanning.com/programs/cindex.pro

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		color table By: Ye Hong on Wed, 26 March 1997 00:00
		Re: color table By: J.D. Smith on Wed, 26 March 1997 00:00
		Re: Color table By: R.Bauer on Thu, 05 August 2004 06:41
		Re: Color table By: R.G. Stockwell on Thu, 05 August 2004 08:46
		Re: Color table By: David Fanning on Wed, 04 August 2004 21:05
		Re: Color table By: David Fanning on Mon, 21 January 2008 07:09
		Re: Color table By: WRC2008 on Thu, 24 January 2008 00:31
		Re: Color table By: WRC2008 on Mon, 21 January 2008 04:35
		Re: Color table By: WRC2008 on Mon, 21 January 2008 02:02
		Re: Color table By: David Fanning on Sun, 20 January 2008 09:53
		Re: Color table By: mmiller3 on Sun, 20 January 2008 07:58
		Re: Color table By: Vince Hradil on Sat, 19 January 2008 10:39
		Re: Color table By: WRC2008 on Sat, 19 January 2008 04:27
		Re: Color table By: David Fanning on Fri, 25 January 2008 05:23
		Re: Color table By: WRC2008 on Fri, 25 January 2008 04:47
		Re: Color table By: WRC2008 on Fri, 25 January 2008 02:35
		Re: Color table By: David Fanning on Fri, 25 January 2008 01:15
		Re: Color table By: WRC2008 on Fri, 25 January 2008 00:54
		Re: Color table By: David Fanning on Thu, 24 January 2008 10:00
		Re: Color table By: WRC2008 on Thu, 24 January 2008 09:41
		Re: Color table By: David Fanning on Thu, 24 January 2008 09:25
		Re: Color table By: WRC2008 on Thu, 24 January 2008 09:02
		Re: Color table By: David Fanning on Thu, 24 January 2008 08:19
		Re: Color table By: WRC2008 on Thu, 24 January 2008 07:17
		Re: Color table By: David Fanning on Thu, 24 January 2008 05:04
		Re: Color Table By: Nikola on Wed, 18 August 2010 05:44
		Re: Color Table By: panblosky on Tue, 17 August 2010 06:32
		Re: Color Table By: Wout De Nolf on Tue, 17 August 2010 05:42
		Re: Color table By: David Fanning on Sat, 10 November 2012 17:38

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