[pdftex] OT: Linux AR 7.0 released: another comment

h h extern pragma at wxs.nl
Mon May 2 10:03:51 CEST 2005


James Quirk wrote:

> The degradation in performance is alarming: AR 7.0 is seventy five times
> slower than AR 5.1 in turning off 2,000 widgets. This would suggest that 

widgets have associated appearance streams (i.e. in a tex field, the text string 
is also internally 'rendered' as a stream of pdf tokens, don't ask me why -) so 
it may be that there is some serious memory allocation/deallocation and messed 
up garbage collection going on (if also javascript is involved, for instance 
because one does checks, even more mem problems may be the cause - i'm still not 
sure if the most recent javascript plug in collects garbage at all); it may well 
be that acrobat 5 was fast because it was bugged and didn't do thinsg it ws 
supposed to do, for instance running calculation and validation javascripts -)

> Adobe's software testing does not run to checking how well the PD format 
> scales. But this would be in keeping with the picture that Nelson paints.

i'm pretty confident that they don't do real torture tests; keep in mind that 
pdftex is one of the few apps that can generate such tests -)

> p.s. Before dismissing the present perfomance test as artificial,
> you might care to look at the documents:
> 
>    http://www.amrita-ebook.org/doc/asme/cfd-policy
>    http://www.amrita-ebook.org/doc/amr2003
> 
> both of which employ 100's of widget annotations to good effect.

in your case you also suffer from slow rendering; it may be that some 500 
widgets on one page result in 500 times repainting the screen due to sycn and 
timing problems; my experience (on windows) is that rendering of complex pages 
is slower then it was before, apart from persistent accuracy problems in some 
situation:

- with regards to math rendering (composed root symbols and such) we're back at 
acrobat 2 quality level
- when for instance transparent us used, anti aliasing is rather poor and 
counter productive (was also true in v 6)
- browser integration is of such quality that one needs to close open browsers 
and kill the mem persistent acrobat process in the hard way

well, one gets accustomed to it, and we have no real reason to complain, since 
so far no one came up with a full featured alternative [for instance pugins to 
xpdf for widget support and ports to other platforms], of widget plugins for 
gsview, or ... [maybe things are simply not so simple]

Hans

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