How use colored cow fonts with pdflatex?

Question

I've successfully downloaded and installed Hoekwater's "cow fonts" so that I can use them with pdflatex — see sample document below. In particular, I'd like brown cows!

But how can one get the colored-cow fonts (or the sheep fonts) with pdflatex? (The TUGboat article [vol. 37 (2016), no. 3, pp. 306-310] "Cowfont (koeieletters) update" by Taco Hoekwater and Hans Hagen shows how to do this with ConTeXt only.

\documentclass[extrafontsizes,48pt]{memoir}
\usepackage[T1]{fontenc}

\DeclareFontFamily{T1}{CowFont}{}
\DeclareFontShape{T1}{CowFont}{m}{n}{<-> koeieletters}{}

\begin{document}

\usefont{T1}{CowFont}{m}{n}

Moo!

\end{document}

From the Hoekwater & Hagen TUGboat article

Here's some of the code from the article that, in ConTeXt, is supposed to produce colored cows (or sheep):

\definecolor[cowred] [r=.50]
\definecolor[cowgreen] [g= . 50]
\definecolor[cowblue] [b=.50] 
\definecolor[cowyellow] [y=.25]
\definefontcolorpalette[cows]
  [cowgreen,cowyellow,cowblue,cowred] 
\adaptfontfeature[sheepcolored] [colr=cows]

\usetypescript[all] [cowsotf]
\definefontcolorpalette[cows-1] cowyellow,cowblue,cowred]
\definefontcolorpalette[cows-2] [cowred, cowyellow,cowblue,cowgreen]
\definefontcolorpalette[cows-3] [cowgreen, cowyellow,cowred,cowblue]

\definefontfeature[cows-1] [cowscolored] [colr=cows-1]
\definefontfeature[cows-2] [cowscolored] [colr=cows-2]
\definefontfeature[cows-3] [cowscolored] [colr=cows-3]

\definedfont[Cows*cows-1 at 30pt] red\quad
\definedfont[Cows*cows-2 at 30 pt] green\quad
\definedfont[Cows*cows-3 at 30pt] blue

The output is supposed to be:

I do not know ConTeXt. And the article does not sufficiently distinguish [at least for me) between what is in the package(s) involved, on the one hand, and what goes into the user's document, on the other hand — a fault all too common in TeX documentation!]. So I don't know which part of the preceding code has to go in the actual document, nor what other code has to be included so as to make working ConTeXt document.

And then, just to confuse things totally (for me), at the very end of the article it says the following.

"To make a quick start with these fonts, you can use one of:

\setupbodyfont[koeieletters]
\setupbodyfont[cows] 
\setupbodyfont[coloredcows] 
\setupbodyfont[sheep] 
\setupbodyfont[coloredsheep]

where the koeieletters variant equals sheep."

Answer 1

I managed the following.

Requirements

• LuaTeX, Version 1.06.0. The binary I got from w32tex.org, happily I already had a setup to use it without disturbing my normal tex system.
• A new fontloader: get luatex-fonts-merged-lua from a current context minimals and tell luaotfload to use it as fontloader with a luaotfload.conf file. (Older fontloaders gave errors).
• a changed luaotfload-letterspace.lua, as the default one doesn't work with a new font loader (I had it already from earlier tests.)
• and naturally the fonts. The emoj font was somewhere in my system, the cow-font I copied from a context minimals (perhaps it is somewhere in texlive too).

Addition

I uploaded to CTAN a package fontloader-luaotfload which contains alternative fontloaders, the changed luaotfload-letterspace.lua and in the documentation some tipps how a development luatex can be used.

The result

I appologize for the colors, but it isn't easy to find out how to change them to something more beautiful.

\documentclass{article}

\directlua{fonts.handlers.otf.registerpalette("demo", {
        { g = 0 },
        { g =0.5 },
        { r = 1  },
        { r = 1, b= 1},
    }
    )}


\begin{document}
\font\Emoj={file:seguiemj.ttf:mode=node;colr=yes;}
     \Emoj \char"2661 \char"1F34D \char"1F986
\font\Emoj={file:seguiemj.ttf:mode=node;colr=demo;}
     \Emoj \char"2661 \char"1F34D \char"1F986

\font\cow={file:koeielettersot.ttf:mode=node;colr=demo;} at 30pt
    \cow ABC

\end{document}    

Addition

I'm getting the hang of the colors. The second entry is for the body of the cow, the fourth for the spots and for the color in the emoij-font. It is the best to set all rgb-values. So this here give orange with blue:

\directlua{fonts.handlers.otf.registerpalette("demo", {
        { g = 0 },
        { g = 0.5, b=0, r=1 },
        { r = 1  },
        { r = 0, b= 1, g= 0},
    }
    )}