| Using color tables in function graphics [message #94783] |
Wed, 11 October 2017 17:05  |
laura.hike
Messages: 87
Registered: September 2013
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Member |
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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
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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
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Senior Member |
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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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| 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
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Senior Member |
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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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| Re: Using color tables in function graphics [message #94788 is a reply to message #94785] |
Thu, 12 October 2017 11:26 |
laura.hike
Messages: 87
Registered: September 2013
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Member |
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I like that -- thanks!
On Thursday, October 12, 2017 at 2:27:11 AM UTC-7, Markus Schmassmann wrote:
> 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?
>>
>
> 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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