Re: Transparent Black, or Are all transparent colors create equal?
One kind of layer that would not have premultiplied alpha would be a
CanvasLayer with a WebGL context with the {premultipliedAlpha:false}
context attribute (what was passed as the 2nd argument to
canvas.getContext).
I did some testing and found a bug,
https://bugzilla.mozilla.org/show_bug.cgi?id=924375 . But I don't know
whether it's related to what's discussed here.
Benoit
2013/10/8 Robert O'Callahan rob...@ocallahan.org
On Mon, Oct 7, 2013 at 3:11 PM, Chris Peterson cpeter...@mozilla.com
wrote:
I stumbled upon some layout code that for transparent colors using != or
== NS_RGBA(0,0,0,0):
http://dxr.mozilla.org/**mozilla-central/search?q=**
regexp%3A%23[!%3D]%3D%20%3FNS_**RGBA%23
http://dxr.mozilla.org/mozilla-central/search?q=regexp%3A%23[!%3D]%3D%20%3FNS_RGBA%23
Are those checks unnecessarily restrictive?
One of the checks has a comment saying Use the strictest match for
'transparent' so we do correct round-tripping of all other rgba()
values,
but the strictness of the other checks is unclear. ;)
All those checks look correct to me. Most of the colors we deal with are
using premultiplied alpha (e.g. the checks in nsDisplayList certainly do),
in which case the only valid alpha value is RGBA(0,0,0,0).
Rob
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Transparent Black, or Are all transparent colors create equal?
I stumbled upon some layout code that for transparent colors using != or == NS_RGBA(0,0,0,0): http://dxr.mozilla.org/mozilla-central/search?q=regexp%3A%23[!%3D]%3D%20%3FNS_RGBA%23 Are those checks unnecessarily restrictive? One of the checks has a comment saying Use the strictest match for 'transparent' so we do correct round-tripping of all other rgba() values, but the strictness of the other checks is unclear. ;) chris ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
Re: Transparent Black, or Are all transparent colors create equal?
On Mon, Oct 7, 2013 at 3:11 PM, Chris Peterson cpeter...@mozilla.comwrote: I stumbled upon some layout code that for transparent colors using != or == NS_RGBA(0,0,0,0): http://dxr.mozilla.org/**mozilla-central/search?q=** regexp%3A%23[!%3D]%3D%20%3FNS_**RGBA%23http://dxr.mozilla.org/mozilla-central/search?q=regexp%3A%23[!%3D]%3D%20%3FNS_RGBA%23 Are those checks unnecessarily restrictive? One of the checks has a comment saying Use the strictest match for 'transparent' so we do correct round-tripping of all other rgba() values, but the strictness of the other checks is unclear. ;) All those checks look correct to me. Most of the colors we deal with are using premultiplied alpha (e.g. the checks in nsDisplayList certainly do), in which case the only valid alpha value is RGBA(0,0,0,0). Rob -- Jtehsauts tshaei dS,o n Wohfy Mdaon yhoaus eanuttehrotraiitny eovni le atrhtohu gthot sf oirng iyvoeu rs ihnesa.rt sS?o Whhei csha iids teoa stiheer :p atroa lsyazye,d 'mYaonu,r sGients uapr,e tfaokreg iyvoeunr, 'm aotr atnod sgaoy ,h o'mGee.t uTph eann dt hwea lmka'n? gBoutt uIp waanndt wyeonut thoo mken.o w * * ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
