On Tuesday 25 March 2008 18:43, MacArthur, Ian (SELEX GALILEO, UK) wrote: > > Both environment show me that 1.1.7 works better > > Be careful though - although 1.1.7 is quicker for your specific test > case, there are many places where 1.1.8 is improved over 1.1.7, so you > are *probably* better off using 1.1.8 overall. > Hmm, I wrote a wrong thing:
I wanted to say: "Both environment show me that fltk 1.1.8 works better without Xdbe support", and in fact performance without Xdbe support are very similar for 1.1.7 and 1.1.8. Effectively I was using 1.1.8 but at some point I noticed that maximixing a double window have had the background black for few seconds, a thing that I don't see normally ... Than, I started some investigation, ending up isolating the problem around the Xdbe feature. After that I looked at Fl_Double_Window.cxx source, (without a deep knowledge of both Fltk internals and X libraries): among other things the only significative changes I'm able to see (related to this issue) is a "copy" flag that is present in 1.1.7 and not in 1.1.8. The "copy" flag is around the code ".... XdbeSwapBuffers ; return ..." Not sure, but it look like a 1.1.7 Xdbe bug, (where XdbeSwapBuffers mostly is not used, even if available, therefore hiding the bad performance of XdbeSwapBuffers). I end up disabling Xdbe, and using 1.1.8, but I think that if this is a common situation user and developers should be warned about. Altought my example was an artifact, nothing of practical use, it showed me that without Xdbe speed was about 3 times than with Xdbe on my systems. Regards Andrea _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
