- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Thu, 13 Feb 2014 09:38:12 -0800
- To: "Dr. Olaf Hoffmann" <Dr.O.Hoffmann@gmx.de>
- Cc: www-svg <www-svg@w3.org>
On Thu, Feb 13, 2014 at 7:01 AM, Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de> wrote: > Cameron McCormack: >> You're right there would be an advantage to allowing fractions in here >> for values like 1/7. On the other hand we don't allow numbers to be >> expressed like this anywhere else in SVG. > > Well due to CSS one can already note font-size/line-height for font with > similar syntax, but different meaning of course. That's a grammar disambiguator, not a fraction. We use / to separate things that could be ambiguous when it's not appropriate to use comma for the job. >> People have previously asked to be able to use CSS length values in the >> middle of path data strings, and <polygon> points attributes. Although >> we hadn't planned on doing that right now, as it's quite a change, it >> would let you do fractions using calc(). > > To have it for already established commands will be more problematic, > because 'calc' represents already four path commands, even more > problematic than b, B without a reasonable fall back mechanism for > current viewers, scripts and programs. No, it doesn't. You can't omit the arguments after the c, a, and l commands, so "calc" showing up in a path command just makes it an invalid path in legacy user agents, no different than any other new addition to the path syntax. > And the parsing might get slower, if a program has to take into account, > that each number can be a calculable expression - > this means effectively something completely new to analyse path data. > The addition of b, B with only degree or with fractions like m/n as well only > require some addition to a currently already working algorithm, and there > will be no big complication due to the fraction notation here. > However, if we forget about a notation in degree, we could > say one has to note pairs of numbers instead of a fraction: > B 3,7 instead of B 3/7 - this would align better with current notations. > The disadvantage of this approach is, that due to current use in SVG, > a notation in degree is what people already know and expect, if they do > not think in specific symmetries. Parsing speed is a complete non-issue; don't worry about it. ~TJ
Received on Thursday, 13 February 2014 17:38:59 UTC