Re: [ft] Stray pixel from FT_Outline_Get_Bitmap()?

[Ian Britten]

On 06/08/10 02:47 AM, Werner LEMBERG wrote:
> > - Even though I'm getting different rasterization results between
> >    2.3.9 and 2.3.11, I can't seem to see anything different being
> >    done.  The output I attached is the same for both versions,
> >    leading me to suspect I'm not looking at the relevant code.
>
> I suggest that you build your product with both 2.3.9 and 2.3.11 and
> do two parallel gdb sessions, inserting breakpoints in the sweep
> functions to find out where the additional pixel gets set.  Then you
> should be able to repeat it with the standalone version of the
> rasterizer.

(sigh) My sincere apology for that last post, as I see now it was
completely useless...
Too many simultaneous things on the go, too many VMs, too many
hack-jobs to system libraries...  In the end, it seems I was
debugging two separate 2.3.9 builds... (Duh!)

Now, on to _real_ 2.3.9 vs 2.3.11 info...   :P

> > - Horizontal_Sweep_Drop() doesn't do anything when called (Bails
> >    early due to leftmost/rightmost stub tests)
>
> Then there aren't any drop-outs to consider during the horizontal
> sweep phase.  This is strange, however, since one of the drop routines
> should be responsible for your additional pixel, I believe.

As you suspected, Horizontal_Sweep_Drop() seems to be the culprit,
and the 2.3.11 changes seem to be producing different results in
the second/final call to it.

I'm not going to try to understand the logic, nor suggest how to
fix it (Not my area of expertise!).  Instead, I've tried to print
out all the relevant information [See attached] to hopefully allow
you to ponder how to best proceed.

If anything isn't there, let me know and I can add more output.  I
realize it's not as ideal as a self-contained test, but I've been
busy debugging my program for now, and haven't got back to trying
to reproduce this in isolation...

Feel free to ask for more info, or to try hacking something, etc.
Thanks,
Ian

ft_239.txt
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ft_2311.txt
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