[OpenJDK 2D-Dev] More incompatibilities

[Hiroshi Yamauchi]

On Tue, Mar 3, 2009 at 7:38 AM, Roman Kennke <roman.kennke at aicas.com> wrote:
> Hi again,
>
>> 3. NotANumberTest: Double.NaN isn't handled gracefully.
>
> The problem here is that the renderer in OpenJDK is originally written
> for ME and uses fixed point arithmetic. I can't think of a quick fix,
> because shapes are processed by iterating over them, this means, by the
> time we hit the NaN, we might already have processed (==rendered) some
> of the shape, but your test seems to suggest that you expect nothing to
> be rendered in this case. The specification doesn't say anything about
> this particular problem (at least I can't find anything). One solution
> would be to pre-check all the incoming shapes for NaN or other invalid
> values (infinity, etc) and not go into the iteration at all. But this
> seems like quite a big overhead to me. We could also make the
> floating->fixed conversion to throw an exception, that we would have to
> catch higher up in the call tree and rollback what has already been
> rendered (which doesn't seem easy either, because in the case of
> strokeTo() this lies outside of the pisces renderer).

The bug analyses sound right to me (though I don't know the code well
enough to fully appreciate :)

Thanks,
Hiroshi

>
> /Roman
> --
> Dipl.-Inform. (FH) Roman Kennke, Software Engineer, http://kennke.org
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