[PATCH] Re: input for fdo#45779 from a basegfx knowledgeable person needed

[Thorsten Behrens]

Pierre-André Jacquod wrote:
> back again after a while.
> 
Hi Pierre-André, welcome back! :)

> It happens that basegfx::GetLineArrow(...) (also defined within
> msdffimp.cxx, line 1102) does not create a valid polygon when
> eLineEnd has the value mso_lineNoEnd...
> In the switch(eLineEnd), this goes to
> >  default: break;
> without creating any polygon, letting the return value undefined.
> 
> So I propose to skip the creation these incorrect polygons if
> eLineEnd has the value mso_lineNoEnd. But since I do not understand
> well the import / translation from msformat, I may also have missed
> a big point. Hence thanks for reviewing this patch, before I push
> it.
> 
Ah, great analysis - true, generating items for stuff that is not
there does not look too sensible. Canonical place that interprets
this for rendering is

 svx/source/sdr/primitive2d/sdrattributecreator.cxx:298

, which is already gated by the StartWidth item - so I'd think we
need to set at least that one, in any case.

Digging a bit deeper, though, e.g.

 sd/source/core/drawdoc4.cxx:175

sets a curious aNullPolyPolygon, so with a bit of bad luck, code
will rely on XLineStartItem/XLineEndItem being set to empty at other
places (counted some 90-odd places where XLineStartItem is used).

So what I suggest is a more defensive fix (or some larger review
across the code is in order): make GetLineArrow() return the
B2DPolyPolygon right away, and have *that one* be empty (i.e. not a
non-empty B2DPolyPolygon with an empty B2DPolygon, as it is now).

That matches the defaults the Impress core sets, so we should be
rather safe. ;)

Cheers,

-- Thorsten
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