[Lib2geom-devel] isZero ...

[Johan E. <jbc...@sw...>]

Hi guys,
  As a result from my changing the definition of isZero (a==0 to 
are_near) on Linear, a bug popped up in Inkscape:
http://pastie.org/pastes/3763503/text?key=mj3yosx9rrc2xkqgzkow

I fixed the issue in Inkscape rev 11212:
http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/11212

Please review and confirm that the fix is correct.

I am in doubt whether at the end of the for-loop,
     Pk.truncate(order);
     Qk.truncate(order);
     r.truncate(order);
should be followed by
     Pk.resize(order,Linear(0.));
     Qk.resize(order,Linear(0.));
     r.resize(order,Linear(0.));
Just to be absolutely sure they have the correct size. The bug happened 
because for some paths, a whole bunch of things were zero, causing 'sg' 
to be zero with zero order.

After this fix, we hit upon another exception, ...
lib2geom exception: Invariants violation (src/2geom/piecewise.h:144)

Note, everthing works fine when changing
    Linear::  inline bool isZero(double eps=EPSILON) const { return 
are_near(a[0], 0., eps) && are_near(a[1], 0., eps); }
to
   a[0]==0 && a[1]==0

Thanks,
   Johan