Re: Multithreading and PCL

[fabien v <f....@laposte.net>]

Hello David,

I have faced the same problem and made multiple investigations.
Here are the 3 steps that seem to fix the multithreading issues with FOP /
PCL :

(1) Fix a bug in sun.font.GlyphLayout, see 
bugs.sun.com/bugdatabase/view_bug.do?bug_id=6367148
bugs.sun.com/bugdatabase/view_bug.do?bug_id=6367148  (using the endorsed
mechanism).

(2) The first FOP warnings appear in the fop layout manager. To avoid this,
I use the fop intermediate format (see 
http://xmlgraphics.apache.org/fop/0.94/intermediate.html
http://xmlgraphics.apache.org/fop/0.94/intermediate.html ). So the
generation sequence is : XSLFO => FOP AREA TREE => FOP PCL.

(3) Then some texts have a wrong place on the generated page. Setting a lock
mechanism in org.apache.fop.render.pcl.PCLRenderer class on the
renderSpace() method have fixed the problem. I don't know exactly why, but
it seems that some resources used by this method have thread-unsafe
operations.

Pfieeewww =^D ! Perhaps someone will have the courage to make further
investigations. No matter what, FOP is really a great tool =) !

Fabien


David Gerdt wrote:
> 
> According to the website documentation on multithreading:
>  
> "There is also a known issue with fonts being jumbled between threads when
> using the Java2D/AWT renderer (which is used by the -awt and -print output
> options). In general, you cannot safely run multiple threads through the
> AWT renderer."
>  
> Three questions:
> 1. Am I correct in my cursory observation that this is also true for the
> PCL renderer?
>  
> 2. If it is the case that the PCL renderer also suffers, can someone
> elaborate on the cause of these problems? A high level, very basic
> understanding is all I'm curious for. I'm definitely inexperienced with
> thread related programming, but from what I gather, the AWT java classes
> are thread safe, correct? Am I making an illogical jump from reading "AWT
> renderer" in the FOP docs and assuming that the problem has something to
> do with the AWT classes in Java?
>  
> 3. Any general pointers on how to use multithreading profitably with the
> PCL renderer? Right now, the app I wrote (standalone socket server) is
> multithreaded but synchronizes access to the Transformer class which seems
> to solve my problem from #1 but basically makes it a single thread program
> again.
>  
> Thanks for any insight.
> 
> 

-- 
View this message in context: http://www.nabble.com/Multithreading-and-PCL-tp17658051p18870089.html
Sent from the FOP - Users mailing list archive at Nabble.com.


---------------------------------------------------------------------
To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org

Re: Multithreading and PCL

[fabien v <f....@laposte.net>]

The right bug link is : 
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6611637 
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6611637  


-- 
View this message in context: http://www.nabble.com/Multithreading-and-PCL-tp17658051p18870154.html
Sent from the FOP - Users mailing list archive at Nabble.com.


---------------------------------------------------------------------
To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org