Re: Cairo: how do I use $cr->append_path to draw a path?

[Torsten Schoenfeld <kaffeetisch gmx de>]

On 07.08.2011 20:05, Torsten Schoenfeld wrote:
> Note that the paths returned by Cairo are implemented as tied array
> references which do not support adding, removing or shuffling of path
> segments.

So you might be wondering why I did not simply choose to convert paths 
to and from native data structures, which would sidestep all the 
problems the current tied representation has.

Well, I actually did just that in my first attempt.  But it turned out 
that, with the native data structure approach, a call to $cr->copy_path 
is about 45 times slower than with the tied approach.  And the 
combination of $cr->copy_path and $cr->append_path is about 25 times 
slower.  I thought that this is too big a slowdown.

But then I stumbled upon an old Perl port of pango's cairotwisted 
example (now committed to master), which fetches, alters and then 
re-appends a rather big path.  And this program is actually about 7 
times faster with the native data structure approach.

So, with the native data structure approach: programs which simply do 
$cr->copy_path and $cr->append_path are slowed down massively, and 
programs which in addition actually alter the path are sped up massively.

Now, which of these behaviors is more common?  I added the branch 
"native-paths" to the git repository: 
<http://git.gnome.org/browse/perl-Cairo/?h=native-paths>.  Can anyone 
benchmark a real-world program against master and native-paths and tell 
us the results?