Re: [NTG-context] Node for startbuffer.

9 Jan 2013

      On 1/9/2013 2:54 PM, Andre Caldas wrote:
...
Hello!
Given some
\startbuffer
   Blah, blah, blah...
\stopbuffer
I'd like to get a "node tree" corresponding to how the buffer would be
processed at a given point. Using luatex, I'd like to identify certain
sub-nodes and change their attributes (to be specific: transparency).
Any hint on how to do it?
here's an example (I'll add it to the cld manual):

\starttext

\definecolor[mytransparency][a=1,t=.5]

\startluacode
local enabled = false
local count   = 0

function userdata.processmystuff(head)
     if enabled then
         count = count + 1
         for n in node.traverse(head) do
             logs.report("node","run %s: %s",count,n)
             if count % 2 == 0 then
                 nodes.tracers.transparencies.set(n,"mytransparency")
             end
         end
         return head, true
     end
     return head, false
end

function userdata.enablemystuff()
     enabled = true
end

function userdata.disablemystuff()
     enabled = false
end

nodes.tasks.appendaction("processors", "normalizers", 
"userdata.processmystuff")
\stopluacode

\startbuffer
whatever \hbox{you} want
\stopbuffer

\ctxlua{userdata.enablemystuff()}
\par \getbuffer \par
\ctxlua{userdata.disablemystuff()}

\stoptext
...
Also, are there any good examples on how to use "nodes"?
all over context ...

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------