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| -rw-r--r-- | luaotfload.dtx | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/luaotfload.dtx b/luaotfload.dtx index f4d39f6..1e4e338 100644 --- a/luaotfload.dtx +++ b/luaotfload.dtx @@ -597,6 +597,43 @@ function luaotfload.unregister_callbacks() 'luaotfload.find_vf_file') end % \end{macrocode} +% +% \subsection{Emulating font dimensions} +% +% And here add some code to emulate \XeTeX's \cs{fontdimen8}, +% which stores the caps-height of the font. (Cf.\ \cs{fontdimen5} which +% stores the x-height.) +% +% Falls back to measuring the glyph if the font doesn't contain the +% necessary information. +% This needs to be extended for fonts that don't contain an `X'. +% +% \begin{macrocode} +local function def_font(...) + local fontdata = fonts.define.read(...) + if fontdata then + local units = fontdata.units + local size = fontdata.size + local otfdata = fontdata.shared.otfdata + + local capheight = otfdata.pfminfo.os2_capheight + + local dimen8 = capheight/units*size + + if capheight <= 0 then + dimen8 = fontdata.characters[string.byte("X")].height + end + + fontdata.parameters[8] = dimen8 + end + return fontdata +end +luatexbase.reset_callback('define_font') +luatexbase.add_to_callback('define_font', + def_font, + 'luaotfload.define_font', 1) +% \end{macrocode} +% % \iffalse %</lua> % \fi |