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

From: Simon Fraser <smfr@me.com>
Date: Mon, 21 Jun 2010 14:33:44 -0700
Cc: Brad Kemper <brad.kemper@gmail.com>, "robert@ocallahan.org" <robert@ocallahan.org>, Brendan Kenny <bckenny@gmail.com>, fantasai <fantasai.lists@inkedblade.net>, "L. David Baron" <dbaron@dbaron.org>, Brian Manthos <brianman@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
Message-id: <8F066FB7-DA62-4A08-83E2-27A2EACE82AA@me.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
On Jun 21, 2010, at 2:31 PM, Tab Atkins Jr. wrote:

> On Mon, Jun 21, 2010 at 2:05 PM, Brad Kemper <brad.kemper@gmail.com> wrote:
>> The size of the blur when you provide a distance measurement for blur can
>> not be irrelevant. It is the primary reason and use case for having blur on
>> a shadow!
> What I mean is that the amount which the blur extends inward really
> doesn't matter to me.  What's most important when I'm blurring a
> shadow is how big the shadow becomes.
>>> I care about how large the shadow
>>> becomes post-blur, and so to me having the length indicate the
>>> distance the blur extends outward from the shadow is most sensical.
>> If you care about how far it extends, you can still figure that out easily
>> (divide by two), if you are worried about it overlapping something, for
>> instance. But for simplicity it should still be a total blur amount
>> specified when specifying blur.
> That's not a strong argument.  I could make an identical "simplicity"
> argument for having the length be the amount it extends outwards and
> inwards, because then the meaning of the length is similar to the
> meaning of the spread length.  After all, if you care about the total
> size of the blurring effect, you can just multiply by two.
>>> Having the blur length match the spread length thematically is an
>>> added bonus - both lengths act similarly and thus are easier to use.
>> Far from it. It just adds confusion to what is being measured, when it can
>> be pretty obvious, based on the extent of the visual effect.
> I've explained why I feel the opposite.  To me, the relevant length to
> measure is the amount the blur extends out from the original shadow,
> same as spread.  The fact that the blur also affects the inside of the
> shadow is just a detail - I could care less how far it does so, so
> long as it looks pretty.
> It certainly doesn't *add* any confusion, though.  In both cases, the
> length will be measuring how much the effect makes the shadow grow
> from the base.  (I'm not saying that your idea isn't coherent in this
> respect either, just defending my own claim.)

I'm with Tab here. And since two browsers already implement it this way, I see no reason to change it.

Received on Monday, 21 June 2010 21:34:29 UTC

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