Well the logical solution is to setup a new math version, which should be independant from the normal math version.
But imho there is today not much chance to get the version key working in your use case. As long as only real math fonts are involved it works fine, but in the combination with range and text fonts it is buggy as one math version affects the other.
Currently I would implement a bold mathversion by embolden a real math font. In xelatex this can be done with FakeBold and version (as long as no other text fonts are involved). In lualatex you could use a pdfliteral:
\documentclass{article}
\usepackage{fontspec,amsmath}
\setmainfont[Ligatures=TeX]{TeX Gyre Pagella}
\usepackage{unicode-math}
\setmathfont{TeX Gyre Pagella Math}
\begin{document}
\[ \hat f(t) = \int_0^t \hat f'(x)\, dx \]
\pdfliteral direct {2 Tr 0.2 w} %the second factor is the boldness
\[ \hat f(t) = \int_0^t \hat f'(x)\, dx \]
\pdfliteral direct {0 Tr 0 w}%
\end{document}
Best Answer
Mplus gets close:
Note: Barbara is right.![amsfonts](https://i.stack.imgur.com/7MfOX.png)
So the answer would be: either a truetype/opentype version of amsfonts, or
unicode-math
can still use legacy fonts, if desired.unicode-math
access is by$\symbb{R}$
.=============
Original post:
I've seen that one before.
A sort of sans libertine/helvetica flavour.
Some random samples, none with a straight leg:
====
For completeness, a fuller gallery, in parts, more systematically arranged.
(1) These are (some of) the ones with "Math" in the font name:
And then in order of decreasing coverage of the Letterlike Symbols unicode block:
(2)
(3)
(4)
(5)
(6)
And arbitrarily stop there, with a coverage of 20 out of 80 glyphs in the block.
There is obviously something very interesting going on with fonts.