I have a document that so far has used mathpazo for everything. I love the texlive distributed Palatino for maths and body text. The small caps in particular are much better than the True Type Palatino on my Mac. However, I want to use my True Type Futura for headings. Thus I decided to use xetex. All is well except I can't work out how to load up Futura without unloading mathpazo. I can use fontspec to load up the True Type Palatino, but that is a big demotion for by body text. I want mathpazo for everything except headings and to use my True Type Futura for headings.
[Tex/LaTex] Use mathpazo for body and math but use a non-tex font (in this case Futura) for headings.
mathpazoxetex
Related Solutions
You have to use "lining figures" fonts for the math alphabets: add the following lines before \begin{document}:
\DeclareSymbolFont{operators}{\encodingdefault}{ppl}{m}{n}
\DeclareMathAlphabet{\mathbf}{\encodingdefault}{ppl}{bx}{n}
\DeclareMathAlphabet{\mathit}{\encodingdefault}{ppl}{m}{it}
so that the alphabets chosen by \mathrm, \mathbf and \mathit will use the family ppl rather than the default family.
Example
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[sc,osf]{mathpazo}
\usepackage[euler-digits]{eulervm}
\usepackage[T1]{fontenc}
\usepackage{mathtools}
\DeclareSymbolFont{operators}{\encodingdefault}{ppl}{m}{n}
\DeclareMathAlphabet{\mathbf}{\encodingdefault}{ppl}{bx}{n}
\DeclareMathAlphabet{\mathit}{\encodingdefault}{ppl}{m}{it}
\begin{document}
Mathpazo text: 1234567890 old-style figures OK.
Euler math with euler-digits:
\begin{align*}
1234567890 \qquad &\text{mathnormal: euler-digits OK} \\
\mathrm{1234567890} \qquad &\text{mathrm: pazo old-style figures OK} \\
\mathit{1234567890} \qquad &\text{mathit: pazo old-style figures italic OK} \\
\mathbf{1234567890} \qquad &\text{mathbf: pazo old-style figures bold OK} \\
\mathbold{1234567890} \qquad &\text{mathbold: euler-digits OK}
\end{align*}$
\end{document}
The answer is surprisingly simple: in your example, the first term in the line
\definetypeface[BerlinSSDB][ss][sans][Berlin Sans FB Demi]
is just an identifier which can be anything. If you want to have a full set (rm + sans), you need to use the same identifier so ConTeXt knows that these fonts form one collection. So here's your example rewritten (I have tested with other fonts because I don't have the ones you use; better use generic fonts for your MWE):
\definetypeface [Oxinabox] [rm] [Xserif] [Minion Pro]
\definetypeface [Oxinabox] [ss] [Xsans] [Berlin Sans FB Demi]
\setupbodyfont [Oxinabox, 12pt]
\setuphead[chapter][
style=\ss,
sectionnumber=yes
]
\setuphead[section][
style=\ss,
sectionnumber=no
]
\starttext
\chapter{Welcome}
A well known text, used to fill space.
\section{H. Rackham 1914}
But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness... But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?
\stoptext
But as others have already said, if you're serious about using ConTeXt, better have a look at luatex/mkiv. It can almost everything that XeTeX can, and then so much more.
Best Answer
I don't think that in the long run you will be very happy with the combination of mathpazo (which needs an encoding like T1 or OT1) and xelatex for normal texts: You won't be able to use a lot of non-ascii chars in the input, e.g. euro and sharp-s will not work. Apart from this: If you want to use a "fontspec font" in the heading you must change the encoding to EU1: