Traversing TeX nodes
From LuaTeXWiki
Traversing TeX nodes[edit]
Put this code at the beginning of any TeX file:
\directlua{
local glyph = node.id('glyph')
local hlist = node.id('hlist')
local vlist = node.id('vlist')
function gothru(h,prof)
for t in node.traverse(h) do
texio.write_nl(string.rep("...",prof) .. 'NODE type=' .. node.type(t.id) .. ' subtype=' .. t.subtype )
if t.id == hlist or t.id == vlist then
texio.write(' w=' .. t.width .. ' h=' .. t.height .. ' d=' .. t.depth .. ' s=' .. t.shift )
gothru(t.list,prof+1)
end
if t.id == glyph then
texio.write(' font=' .. t.font .. ' char=' .. t.char .. ' width=' .. font.fonts[t.font].characters[t.char]['width'])
end
end
end
callback.register('pre_linebreak_filter',
function(h)
gothru(h,0)
return true
end
)
}
It will display a list of all nodes on the terminal and in the log file. For example, for the document
\font\x=omlgc \x blε bla bla bla
which contains a Greek letter (in UTF-8), you will get:
This is luaTeX, Version 3.141592-snapshot-2007062922 (Web2C 7.5.6) ( NODE type=whatsit subtype=6 NODE type=hlist subtype=0 NODE type=glyph subtype=0 font=51 char=98 NODE type=glyph subtype=0 font=51 char=108 NODE type=glyph subtype=0 font=51 char=941 NODE type=glue subtype=0 NODE type=glyph subtype=0 font=51 char=98 NODE type=glyph subtype=0 font=51 char=108 NODE type=glyph subtype=0 font=51 char=97 NODE type=glue subtype=0 NODE type=glyph subtype=0 font=51 char=98 NODE type=glyph subtype=0 font=51 char=108 NODE type=glyph subtype=0 font=51 char=97 NODE type=glue subtype=0 NODE type=glyph subtype=0 font=51 char=98 NODE type=glyph subtype=0 font=51 char=108 NODE type=glyph subtype=0 font=51 char=97 NODE type=glue subtype=0 Underfull \hbox (badness 10000) in paragraph at lines 14--15 [1] )
Be aware of the fact that the nodes will be created only if the glyph requested indeed exists in the font.
Yannis.Haralambous 02:52, 4 July 2007 (EDT)
