W3C home > Mailing lists > Public > www-svg@w3.org > February 2015

Re: Numerical Limits in SVG coordinates?

From: Amelia Bellamy-Royds <amelia.bellamy.royds@gmail.com>
Date: Mon, 2 Feb 2015 18:41:57 -0700
Message-ID: <CAFDDJ7wkg_D+0TDJe3o+0Q-uGguNyuXVdPB6s293oM+q2PoEZw@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>, www-svg <www-svg@w3.org>
Ooops!  That's what I get for whipping up an answer without actually
testing anything...  Thanks for checking Rik.

I didn't look closely to see how small the deltas were compared to the
magnitude in the shape coordinates.   I looked at the viewBox, and thought
the overall coordinate system dimensions to absolute value was still
reasonable enough that the lower-precision digits wouldn't be significant.
I didn't factor in the transform on the shape.

For Thomas, this clearly wasn't the answer you wanted to hear, but a
normalization process is definitely going to be necessary.  You'll need to
figure out a way to store the information about that conversion process
(and the original coordinates) in metadata, and access it when necessary to
align multiple drawings.

ABR

On 2 February 2015 at 18:12, Rik Cabanier <cabanier@gmail.com> wrote:
>
>
> Actually not :-)
> Single precision floats have 6 to 9 digits of precision [1] depending how
> you convert, so Thomas' example might be losing details even on conforming
> readers.
> I saved his example to a fiddle and only IE is able to display it:
> http://jsfiddle.net/d31nv0sy/1/
> Chrome, Safari and Firefox all show a blank page.
>
>
Received on Tuesday, 3 February 2015 01:42:24 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 8 March 2017 09:47:39 UTC