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Re: [css3-background] vastly different takes on "blur"

From: Robert O'Callahan <robert@ocallahan.org>
Date: Wed, 23 Jun 2010 14:25:42 +1200
Message-ID: <AANLkTil7bhCA75sn3TYcwnUQNdbOPvUQOR4gxqtKN019@mail.gmail.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: Simon Fraser <smfr@me.com>, Brad Kemper <brad.kemper@gmail.com>, fantasai <fantasai.lists@inkedblade.net>, Brian Manthos <brianman@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
On Wed, Jun 23, 2010 at 1:11 PM, Tab Atkins Jr. <jackalmage@gmail.com>wrote:

> Roc, does Firefox have similarly buggy behavior with shadows > 8px?
> Like I said, I looked in both Firefox and Chrome with a 100px blur
> shadow, and they both agreed that the shadow extended outwards by
> approximately 50px.  (By the way, FF's text-shadows are absolutely
> beautiful at large sizes - good job.)
>

Thanks. We don't have any special treatement of radii > 8px.

Given a glyph 104px wide and a text-shadow blur radius of 100px, the band of
not-completely-transparent pixels in the shadow is at least 257px wide (the
shadow is wider but pixels attenuate to alpha=0 due to rounding, as
previously noted). So the shadow is definitely extending by 100px on each
side of the glyph. If it were only extending by 50px, the shadow could be no
wider than 204px. Testcase:
data:text/html,<meta http-equiv="Content-Type" content="text/html;
charset=utf-8"><p style="font-size:300px; text-shadow: 400px 0 100px
black;">❚</p>

That's not surprising since the same code does the blurring for box-shadow
and text-shadow and we pass the blur parameter in the same way at both call
sites.

Rob
-- 
"He was pierced for our transgressions, he was crushed for our iniquities;
the punishment that brought us peace was upon him, and by his wounds we are
healed. We all, like sheep, have gone astray, each of us has turned to his
own way; and the LORD has laid on him the iniquity of us all." [Isaiah
53:5-6]
Received on Wednesday, 23 June 2010 02:26:12 GMT

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