Hi Wolfgang, Thank you for your reply. I did as you suggested but it still never worked. However it did make me delve further into the Metafun, LuaMetaFun and the Colouring ConTeXt manuals where I found examples of the *resolvedcolor* helper which I used as follows: definecolor [name = "myColor", r = uniformdeviate(1), g = uniformdeviate(1), b = uniformdeviate(1)]; for loop.. fill unitsquare xscaled 5cm yscaled .5cm shifted (7cm,i*cm) withcolor(r[resolvedcolor("myColor"), white]); endfor; I also found the *namedcolor* helper and I could use it as follows: fill unitsquare xscaled 5cm yscaled .5cm shifted (1cm,(2*i)*cm) withcolor namedcolor("myColor2") ; However, for some reason it did not work in: fill unitsquare xscaled 5cm yscaled .5cm shifted (7cm,i*cm) withcolor(r[namedcolor("myColor"), white]); // Thanks again for your suggestion// Best Wishes Keith// On 28/04/2022 16:04, Wolfgang Schuster wrote:
Keith McKay via ntg-context schrieb am 28.04.2022 um 12:05:
Hi,
In the MWE below I define an rgb colour, myColor1, using random numbers for the r, g and b components. I then use it to fill a unitsquare the size of the page, which works as expected. In the loop that follows I then use the defined colour, myColor1, along with white and the variable r to create shades of myColor1 as in the MWE below. However, myColor1 is not recognised in the loop and seems to be replaced by black, although if I use a predefined colour, in this case BurntSienna from the crayola collection, it works as expected. I have tried a number of ways to get this to work as shown in the code but without success. I would be grateful for any suggestions.
Best Wishes
Keith McKay
%%%%%%%%%%%%%%%%%%%%MWE%%%%%%%%%%%%%
\setuppapersize[A4,portrait]
\usecolors[crayola]
\starttext
\dorecurse{10}{
\startMPpage
StartPage;
\definecolor[name="myColor1", r = uniformdeviate(1), g = uniformdeviate(1), b = uniformdeviate(1) ] ;
Remove the backslash in front of the definecolor command.
Wolfgang