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Re: Using color tables in function graphics [message #94784 is a reply to message #94783]

Wed, 11 October 2017 20:36

Jim Pendleton
Messages: 165
Registered: November 2011

Senior Member

On Wednesday, October 11, 2017 at 6:05:02 PM UTC-6, laura...@gmail.com wrote:
> I would like to plot multiple lines on the same set of axes and I would like each line to be a different color where the colors follow a specific IDL color table (e.g., rainbow and white = 39). In direct graphics, I could use
>
> loadct, 39
>
> then specify the colors using indices from 0 to 255. I can't find any way to do this in function graphics. Most functions only allow colors to be specified by names. The only exception I can find is using the rgb_table property with "plot," but this just applies the colors to the individual points in a line. Does anyone know a way to do this?
>
> Thanks,
>
> Laura

One approach is to retrieve the color vectors from the specified color table, then apply the colors as RGB triplets like this:

IDL> loadct, 39
% LOADCT: Loading table Rainbow + white
IDL> tvlct, r, g, b, /get
IDL> p = plot(findgen(10), findgen(10), color = [r[100], g[100], b[100]])
IDL> p = plot(findgen(10), findgen(10)/2, color = [r[200], g[200], b[200]], /overplot)

In direct graphics with non-decomposed colors, this would be like

IDL> device, decomposed = 0
IDL> loadct, 39
IDL> plot, findgen(10), findgen(10), color = 100
IDL> oplot, findgen(10), findgen(10)/2, color = 200

Jim P.

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[Message index]

		Using color tables in function graphics By: laura.hike on Wed, 11 October 2017 17:05
		Re: Using color tables in function graphics By: Jim Pendleton on Wed, 11 October 2017 20:36
		Re: Using color tables in function graphics By: Markus Schmassmann on Thu, 12 October 2017 02:27
		Re: Using color tables in function graphics By: laura.hike on Thu, 12 October 2017 11:26

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