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Re: Using color tables in function graphics [message #94785 is a reply to message #94784]

Thu, 12 October 2017 02:27

Markus Schmassmann
Messages: 129
Registered: April 2016

Senior Member

On 10/12/2017 05:36 AM, Jim P wrote:
> 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?
> 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
; use the VERT_COLORS keyword:

p=!null
for i=0,9 do p=plot( sin(!dpi*[0:2:.1]+i*.2), $
overplot=p,vert_colors=25*i,rgb_table=39 )

Markus

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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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