Patrick: Copied from the old bluwiki.com luatex wiki

2010-12-07T21:23:34Z

Copied from the old bluwiki.com luatex wiki

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This example code for mirroring characters that has Bidi_Mirrored property (as defined by Unicode) in RTL contexts. It uses characters.data table defined in [http://source.contextgarden.net/tex/context/base/char-def.lua char-def.lua] file from ConTeXt distribution to get character properties.

<pre>
dofile("char-def.lua") -- character definition table

local function mirror(hlist)
local rtl = false
if tex.textdir == "TRT" then
rtl = true
elseif tex.textdir == "TLT" then
rtl = false
end
for n in node.traverse(hlist) do
if n.id == node.id('hlist') then
mirror(n.list)
end
if n.id == node.id("whatsit") and n.subtype == 7 then
if n.dir == "+TRT" or n.dir == "-TLT" then
rtl = true
elseif n.dir == "-TRT" or n.dir == "+TLT" then
rtl = false
end
end
if n.id == node.id('glyph') then
if rtl then
local char = n.char
local mirror = characters.data[char].mirror
if mirror then
n.char = mirror
end
end
end
end
end

callback.register('pre_linebreak_filter',
function(h)
mirror(h)
return true
end
)
</pre>

Example usage:
<pre>
\directlua{dofile("mirror.lua")}

(Left to right) {\textdir TRT (RIGHT TO LEFT)}

\textdir TRT

RIGHT [TO] LEFT (TEXT)

\textdir TLT

left [to] right (text)
\bye
</pre>

--khaledhosny

Mirror characters with Bidi Mirrored property - Revision history

Patrick: Copied from the old bluwiki.com luatex wiki