Weird behavior when using small caps and slanted fonts with fontspec in XeLaTeX

Question

I use XeLaTeX and the fontspec package.

Now, I like to use Linux Libertine as standard font. The slanted (not italics) characters are stored in a different font. Now, to use them with \slshape, I have to select them explicitly:

\setmainfont[
    SlantedFont={Linux Libertine Slanted O},
    SmallCapsFeatures={Letters=SmallCaps},
    Mapping=tex-text, Numbers=OldStyle, Variant=01, Ligatures={TeX, Common}, Contextuals=WordFinal,
    % Style=Alternate, Ligatures={Rare, TeX, Common}
            ]{Linux Libertine O}

As you can see, the slanted font is selected in the SlantedFont={Linux Libertine Slanted O} argument.

When I use \slshape in my document now:

{\slshape \lipsum[1-2]}

It creates the correct slanted text.

(\usepackage{lipsum} is further up in the file.)

Now, when I want to use small caps I use \scshape:

{\scshape \lipsum[3-4]}

The text is slanted small caps! To circumvent this, I have to comment out the SlantedFont argument in \setmainfont, this makes the small caps upright, but I lose slanted text capabilities.

How do I make both behave corectly?

Answer 1

adding ItalicFeatures gets you part of the way there...my eyes aren't good enough to tell the difference....

\setmainfont[
    ItalicFont={Linux Libertine O}, ItalicFeatures={SmallCapsFont={Linux Libertine O Italic}},
    SlantedFont={Linux Libertine Slanted O},
    SmallCapsFont={Linux Libertine O},
    SmallCapsFeatures={Letters=SmallCaps},
    Mapping=tex-text, Numbers=OldStyle, Ligatures={TeX, Common}, Contextuals=WordFinal,
            ]{Linux Libertine O}

 {\slshape Abc}

{\scshape Def}

 {\scshape\itshape Ghi}

{\scshape\slshape Lmn}%

an image similar to above....GHI and Lmn are the same...but slanted or italic

Answer 2

In this particular case it's sufficient to omit the SmallCapsFeatures key:

\documentclass{article}
\usepackage{fontspec}
\setmainfont[
    SlantedFont={Linux Libertine Slanted O},
    SmallCapsFont={Linux Libertine O},
    SmallCapsFeatures={Letters=SmallCaps},
    Mapping=tex-text, Numbers=OldStyle, Ligatures={TeX, Common}, Contextuals=WordFinal,
            ]{Linux Libertine O}
\begin{document}
{\slshape Abc}

{\scshape Def}

{\scshape\itshape Ghi}

{\scshape\slshape Lmn}

\end{document}