Re: Rectangle height and width

While I agree with you both that it would be a mathematical convenience to
define negative width/height as an inversion of the rectangle, but I think
it is far too late to change this now. The restriction on negative numbers
has been there since the beginning and is supported universally.

Furthermore, with SVG 2 conversion of width and height to presentation
attributes with matching CSS properties means that we need to match the
syntax used for the CSS properties, which have the same restriction.

In contrast, the startOffset restriction was changed much earlier on, and
didn't affect any other specifications.

~Amelia

On 9 June 2018 at 08:20, David Dailey <ddailey@zoominternet.net> wrote:

> Fwiw, I kinda like the use case. It makes sense to me. (which sometimes
> proves to be a mark of doom for suggestions SVG, so apologies if my
> weighing in jinxes the idea.)
>
> I would concur that "there are probably other places in the spec where
> negative values are unnecessarily restricted."
>
> I remember back around 2008 strolling through Nuremberg with Eric
> Dahlstrom and complaining that this example:
> http://srufaculty.sru.edu/david.dailey/svg/newstuff/textpath1.svg didn't
> work as I thought it should, because the value of startoffset on a textPath
> was confined to being non-negative. He replied that no one had quite
> imagined doing that particular thing, but that it made sense. Within a few
> years this example ran in all browsers (this was pre-IE-SVG, so one used
> the Adobe plugin).
>
> Cheers
> David
>
> -----Original Message-----
> From: Steven Pemberton [mailto:steven.pemberton@cwi.nl]
> Sent: Saturday, June 09, 2018 7:43 AM
> To: www-svg@w3.org
> Subject: Rectangle height and width
>
> https://svgwg.org/svg2-draft/shapes.html#RectElement
>
> "The width and height properties define the overall width and height of
> the rectangle. A negative value for either property is illegal and must
> be
> ignored as a parsing error."
>
> Please please please fix this! There is absolutely no abstract
> justification for saying a rectangle cannot have a negative height (or
> width). It's just the same dimension in the other direction!
>
> If you're interested in a very natural use case, please see
> https://homepages.cwi.nl/~steven/xforms/histogram.html
>
> (There are probably other places in the spec where negative values are
> unnecessarily restricted, but this is the one that I ran into in the
> above
> example).
>
> Best wishes,
>
> Steven Pemberton
> CWI, Amsterdam
>
>
>
>
>