# Use a TrueType font

A TrueType (or Openype) font can be used without going through a TFM or an OFM file, like in XeTeX.

The best way to do so is to use the package luaotfload, on the CTAN, and developped here: http://github.com/mpg/luaotfload/

The code shows how we can use the table of a TrueType font to produce an internal TeX font table:

```\pdfoutput1
\directlua{
callback.register('define_font',
function(name, size)
fonttype = nil
filename = kpse.find_file(name,"opentype fonts")
if (filename)
then fonttype = 'opentype'
else filename = kpse.find_file(name, "truetype fonts")
end
if filename and not fonttype then fonttype = 'truetype' end
if fonttype then
if (size < 0) then size = (- 655.36) * size end
ttffont = fontforge.to_table(fontforge.open(filename))
if ttffont then
f = { }
f.name = ttffont.fontname
f.fullname = ttffont.names[1].names.fullname
f.parameters = { }
f.designsize = size
f.size = size
direction = 0
f.parameters.slant = 0
f.parameters.space = size * 0.25
f.parameters.space_stretch = 0.3 * size
f.parameters.space_shrink = 0.1 * size
f.parameters.x_height = 0.4 * size
f.parameters.extra_space = 0
f.characters = { }
local mag = size / ttffont.units_per_em

names_of_char = { }
for char, glyph in pairs(ttffont.map.map)
do
names_of_char[ttffont.glyphs[glyph].name]
= ttffont.map.backmap[glyph]
end

names_of_glyph = { }
for char, glyph in pairs(ttffont.map.map)
do
names_of_glyph[ttffont.glyphs[glyph].name]
= glyph
end

for char, glyph in pairs(ttffont.map.map)
do
glyph_table = ttffont.glyphs[glyph]

f.characters[char] = {
index = glyph,
width = glyph_table.width * mag,
name = glyph_table.name,
}
if glyph_table.boundingbox[4] then
f.characters[char].height = glyph_table.boundingbox[4] * mag
end
if glyph_table.boundingbox[2] then
f.characters[char].depth = -glyph_table.boundingbox[2] * mag
end

if glyph_table.kerns then
local kerns = { }
for _, kern in pairs(glyph_table.kerns)
do
kerns[names_of_char[kern.char]] = kern.off * mag
end
f.characters[char].kerns = kerns
end
end
f.filename = filename
f.type = 'real'
f.format = fonttype
f.embedding = "subset"
f.cidinfo = {
ordering = "Identity",
supplement = 0,
version = 1
}
end
else
end
return f
end
)
}
```

The index of the f.characters table is the Unicode value, among the properties of each entry of that table we have index which is the glyph index. Using this property we get the mapping between Unicode characters and glyphs. Kerning is handled via TeX font LKP.

What is missing in the code above is better calculation of standard TeX font parameters and OpenType features. � suivre...