add option to white marker label color

[mkaulisch]

some colors in the scheme / colorpalette I need to use due to corporate design are so dark that white would be a better choice as mlabcolor(). Not sure if there is a way to determine it automatically by colorpalette - but an option to say e.g. color 3 = white - would be cool.

[mkaulisch]

It would be cool if the labcolor()-option from the sunburst-package can be ported to treemap (asjadnaqvi/stata-sunburst#3 (comment)).

[mkaulisch]

Dear @asjadnaqvi, I propose the following changes to the code:
Insert after line 673

            mata: S = ColrSpace()
            mata: S.colors("black `r(p`clr0'name)'")
            mata: st_local("contrast_black",strofreal(S.contrast((1,2))))
            
            if `contrast_black' > 4.5 {
	            local mlabcolor "black"
            }
            if `contrast_black' <= 4.5 {
	            local mlabcolor "white"
            }

Then change all mlabc(black) into mlabc(mlabcolor')`

I tested it with my use case and it works.

[mkaulisch]

My code above only works with named colors. I try to find a way to get the RGB values working...

[asjadnaqvi]

Marc, can you give an example figure to show what you are trying to do?

[mkaulisch]

Of course:
My own program is called treemap2:

cwf default
cap frame drop auto
frame create auto
cwf auto
sysuse auto

split make, parse(" ") gen(brand)
ren brand1 brand
egen model = concat(brand2 brand3)

treemap2 weight, by(brand model) ///
		addtitles palette(hhu_color_fak) ///
		name(brand_model, replace)

[mkaulisch]

With the palettes that do not use named colors - it does not work. But I am a Mata Newbie - so no clue how to do it the best way. It should be possible to add the RGB into the color list and then to contrast them...

[asjadnaqvi]

Ok so for darker background colors, the label color should be lighter in order to increase the contrast for readability.

I prefer having a generic solution that can be added to all packages. For sure it will be very useful. For example bimap, labels are not visible with darker colors. I will have a look!

[mkaulisch]

This code-addition also works with the tableau-palette without named colors:

            mata: S = ColrSpace()
            mata: S.colors("black")
            mata: S.add_Colors("rgb `r(p`clr0')'")
            mata: st_local("contrast_black",strofreal(S.contrast((1,2))))
            
            if `contrast_black' > 4.5 {
	            local mlabcolor "black"
            }
            if `contrast_black' <= 4.5 {
	            local mlabcolor "white"
            }