| Re: problem with color table, everything is red [message #82135 is a reply to message #82050] |
Mon, 19 November 2012 08:46  |
Jeremy Bailin
Messages: 618
Registered: April 2008
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Senior Member |
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On 11/19/12 5:24 AM, Helder wrote:
> On Monday, November 19, 2012 11:13:37 AM UTC+1, simona bellavista wrote:
>> I am having a hard time understanding colors in IDL. I am working on
>>
>> x11 (linux).
>>
>> I would be glad if someone can give me some tips about colors and
>>
>> color tables.
>>
>>
>>
>> when I try to load rainbow color table and display it with
>>
>>
>>
>> loadct, 13
>>
>> tv, dist(300)
>>
>>
>>
>> I always get a color panel that is in grey scale, I have tried to load
>>
>> several color tables, but the resulting color panel I get is always in
>>
>> shade of greys.
>>
>>
>>
>> Moreover, if I try to plot different part of my graphics with
>>
>> different colors, using something like this:
>>
>>
>>
>> for i=0,n-1 do begin
>>
>> indx = start[i] + indgen(start[i+1]-start[i])
>>
>> color = floor(i *255 / float(nlines))
>>
>> oplot,x[indx],y[indx],color=color
>>
>> endfor
>>
>>
>>
>> I get my plot in shades of reds. I tried cgplot and it is the same.
>>
>>
>>
>> then in a subsequent plot I try to revert to black and white, and I
>>
>> use
>>
>>
>>
>> plot, xx, yy,color=255, psym=2, symsize=2,
>>
>>
>>
>> but everything turn red.
>>
>>
>>
>> where shall I start?
>
> Hi,
> this is generally a good place to start from: http://www.idlcoyote.com
> But specifically you are looking for this:
> http://www.idlcoyote.com/misc/tg_working_with_color.pdf
>
> On page 34 there are some extra Linux tips.
>
> Then you should learn about the
> Device, Decompose=1
> command.
>
> You will soon enough find out that not everything in IDL is grayscale and red :-)
>
> Cheers,
> Helder
>
I would also highly recommend David's graphics book:
http://www.amazon.com/Coyotes-Guide-Traditional-IDL-Graphics /dp/0966238354/ref=sr_1_1?ie=UTF8&qid=1353343563&sr= 8-1&keywords=david+fanning
-Jeremy.
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