Re: st: Access scheme colors in program

[Nick Winter <njgwinter@gmail.com>]

If I'm understanding correctly, you can access the relevant thing by 
specifying, in quotation marks "scheme whatever", where whatever is the 
style from which you'd like to draw the color (or whatever):

sysuse auto
twoway connected weight price , mcolor("scheme p3")

or

twoway connected weight price , mcolor("scheme p3") mfcolor("scheme 
background")


I'm not sure if this is documented anywhere..

Nick Winter


On 3/31/2014 12:33 PM, Thomas Grund wrote:
> Dear Statalist
>
> Short version: Is there a way to get direct access to the color codes
> used in -schemes for programming? (long version below)
>
> Thanks,
> Thomas
>
>
> ************************
> Dr Thomas Grund
> Marie Curie Fellow
> Institute for Futures Studies
> Department of Sociology, Stockholm University
>
>
>
> Keywords: schemes, programming, twoway
>
> Long version:
>
> There are four variables in my dataset (x y z_color z_size) and I
> wrote a program that generates and overlays -scatter syntax for each
> unique combination of z_color and z_size in such a way that the size
> of nodes and the color of the dots correspond to my data.
>
> Example data:
> x              y              z_color z_size
>
> 5              5              1              10
> 2              2              1              10
> 5              7              1              20
> 5              7              2              20
> 3              6              2              20
>
> Applied to this data my program produces this syntax:
>
> twoway (scatter x y if z_color = 1  & z_size == 10, msize(10) mcolor(green)) ||
> (scatter x y if z_color = 1 &  z_size == 20, msize(20) mcolor(green)) ||
> (scatter x y if z_color = 2  & z_size == 20, msize(20) mcolor(blue))
>
> As you can see, my program produces one -scatter command for each
> unique combination of z_color and z_size. I solved the coloring by
> specifying the -mcolor option and drawing from a user-defined color
> palette (here, simply green and blue).  The program works fine and
> does exactly what I want. However, I would like to make the coloring
> work with -schemes. That does not seem trivial because schemes define
> colors and other styles for overlaid plots (p1 p2....). In the example
> above, however, I overlay three plots, but only want to use two
> different colors. I would like to access the colors in a -scheme
> directly (in a program) and assign some plots (here, the first and
> second -scatter command) the same color.  One could cheat a little and
> solve this by creating a customized  -scheme. For example,
>
> Example scheme :
> myscheme.scheme:
>
> color p1 green
> color p2 green
> color p3 blue
> ....
> twoway (scatter x y if z_color = 1  & z_size == 10, msize(10)) ||
> (scatter x y if z_color = 1 &  z_size == 20, msize(20)) ||
> (scatter x y if z_color = 2  & z_size == 20, msize(20) ), scheme(myscheme)
>
> However, this is not really a solution for other data. Does anybody
> know how I could get access to the colors defined in a scheme within a
> program? This must be possible somehow, but it is not documented and I
> cannot find anything about it online.
>
> One solution that comes to my mind is to pre-process a scheme by
> reading the .scheme file as text and parse out the color codes that I
> want (p1 p2 p3), but this strikes me as overly complicated....
>
> Any help would be greatly appreciated.
>
> Thanks
>
> Thomas
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