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Re: SVG-ACTION-3765: Add a note about avoiding unitless values

From: Amelia Bellamy-Royds <amelia.bellamy.royds@gmail.com>
Date: Fri, 6 Mar 2015 07:49:22 -0700
Message-ID: <CAFDDJ7zku5W-DOZZD0=7=Y4NkADr_X2wFqVgAH-f0vwWMOWi+w@mail.gmail.com>
To: SVG Working Group <public-svg-wg@w3.org>
Cc: "Little, Chris" <chris.little@metoffice.gov.uk>
On 6 March 2015 at 07:19, Little, Chris <chris.little@metoffice.gov.uk>
 wrote:
>
> Can I suggest that avoiding the term 'unitless' may be a good idea, and
> something like 'unspecified', 'default' or 'inherited' unit may be better.
>

The interfaces currently use the terms "number"  for lengths and
"unspecified" for angles:

http://www.w3.org/TR/SVG11/types.html#__svg__SVGLength__SVG_LENGTHTYPE_NUMBER
http://www.w3.org/TR/SVG11/types.html#__svg__SVGAngle__SVG_ANGLETYPE_UNSPECIFIED

Since using "number" for a length unit is even more confusing than using
"unitless", my vote would be for "lengths/angles with unspecified units".

Example usage:

Within the SVG `transform` attribute:

   - Translation parameters are <length> values; lengths with unspecified
   units are treated as `px` (user units).
   - Rotation and skew parameters are <angle> values; angles with
   unspecified units are treated as degrees, and
   - Scale parameters are unitless <number> values.

That said, I'd be entirely fine with "default units" as well: "the default
unit for length is `px`; the default unit for angles is degrees".

I don't think "inherited" makes sense in this context.
Received on Friday, 6 March 2015 14:49:50 UTC

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