italic (PR#7932)

On Wed, 15 Jun 2005 ligges at statistik.uni-dortmund.de wrote:

ggrothendieck at gmail.com wrote:

Full_Name: G. Grothendieck
Version: R version 2.1.0, 2005-05-14
OS: Windows XP
Submission from: (NULL) (216.59.254.207)


This code:

plot(1:10)
text(5,5,lab=expression(italic(22*"33")))

For mathematical non-character-string annotation a math font is used
that does not support italic/bold/bolditalic/plain.
It seems to be worth adding this information to ?plotmath, such as:
"(only for characters, but not for math font)".

I don't think that is true: plotmath uses the same 5 fontfaces as any
other form of graph annotation.  The reason was staring Grothendieck
in the face: the code is

static BBOX RenderNumber(SEXP expr, int draw, mathContext *mc,
                        R_GE_gcontext *gc, GEDevDesc *dd)
{
    BBOX bbox;
    FontType prevfont = SetFont(PlainFont, gc);
    bbox = RenderStr(CHAR(asChar(expr)), draw, mc, gc, dd);
    SetFont(prevfont, gc);
    return bbox;
}

so it is by design.  Numeric constants are always in PlainFont.