W3C home > Mailing lists > Public > www-style@w3.org > May 2012

[css3-background] Fixing the computed value line for some properties

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Mon, 21 May 2012 16:51:35 -0700
Message-ID: <CAAWBYDAVg=-Z9r_k-DikVwqahsf9mbYq970xzZPUyASMfZCWhQ@mail.gmail.com>
To: www-style list <www-style@w3.org>
I was just writing the note about computed value comparison for the
toggle() function in V&U and wanted to use box-shadow as an example,
but I realized the computed-value line for it doesn't actually support
what I'm trying to say.  It gives the computed value as "any <length>
made absolute; any specified color computed; otherwise as specified",
which means that "0px 0px blue" and "0px 0px 0px blue" would be
counted as different value if the instructions were followed
literally, and thus would trigger transitions, etc.

This is just an editorial oversight, and can be easily corrected.
I've also taken the opportunity to review the other properties in the
draft, and have similar corrections for a few.

background-color: "The computed color" (Right now it says "color(s)"
unnecessarily, since you can only give a single one.)

background-size: "Either 'contain' or 'cover', or a pair of sizes, one
for each axis, each given as either an absolute length, a percentage,
or 'auto'"  (This attempts to mirror the background-position language,
but may be clumsy. I'm totally fine with tweaking the language a bit
to make it sound better/less verbose.)

border-image-slice: "four numbers or percentages, and optionally the
'fill' keyword"

border-image-width: "four numbers, absolute lengths, percentages, or keywords"

border-image-outset: "four numbers or absolute lengths"

border-image-repeat: "two keywords, one per dimension"

box-shadow: "a list of shadows, each with two offsets, a blur, a
spread, and a color, with any <length> made absolute and all colors
computed"

~TJ
Received on Monday, 21 May 2012 23:52:44 GMT

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