[cairo] xlib bug, with testcase
vladimir at pobox.com
Mon Jul 14 16:43:18 PDT 2008
Hmm, I don't see this fix in the pixman repo -- did it get pushed up?
On May 28, 2008, at 11:56 AM, Behdad Esfahbod wrote:
> On Wed, 2008-05-28 at 14:25 -0400, Antoine Azar wrote:
>> Hey Vlad,
>> There are rendering problems on Win32 too. I traced it, and the bug
>> seems to
>> be coming from the fbCompositeSrc_x888xnx8888mmx function.
>> If you comment out this loop, it all works fine:
>> while (w >= 16)
>> __m64 vd0 = *(__m64 *)(dst + 0);
>> __m64 vd1 = *(__m64 *)(dst + 2);
>> *(__m64 *)(dst + 14) = vd7;
>> w -= 16;
>> dst += 16;
>> src += 16;
>> That's a temporary fix, I have no idea what the problem inside this
>> might be, maybe Fred can shed some light.
> That function is not ignoring source alpha as it should be. Attaching
> fix. Going to do a quick review of other places that may have the
>> I'm attaching my resulting images, with and without MMX, and opaque
>> non-opaque. The non-opaque ones are fine because we're calling a much
>> simpler code path, although the MMX version still gives a different
>> from the non-MMX one.
>>> -----Original Message-----
>>> From: cairo-bounces at cairographics.org
>>> [mailto:cairo-bounces at cairographics.org] On Behalf Of
>>> Vladimir Vukicevic
>>> Sent: Tuesday, May 27, 2008 7:51 PM
>>> To: cairo at cairographics.org
>>> Subject: [cairo] xlib bug, with testcase
>>> This showed up as https://bugzilla.mozilla.org/show_bug.cgi?
>>> -- it seems to happen on linux and win32, though I haven't
>>> tried reproducing it on win32. The attached testcase shows
>>> the problem; I've also attached the ref rendering from the
>>> image backend. If the first paint_with_alpha has an alpha
>>> value less than 1.0, then..
>>> strange things happen, I'm not even sure exactly what. I'll
>>> try to figure out a regression range in the next few days,
>>> though if someone wants to beat me to it, please feel free :)
>>> - Vlad
>> cairo mailing list
>> cairo at cairographics.org
> "Those who would give up Essential Liberty to purchase a little
> Temporary Safety, deserve neither Liberty nor Safety."
> -- Benjamin Franklin, 1759
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