[svg2] Empty path data + getPointAtLenght / getPathSegAtLength

Hi,

what should SVGPathElement.getPointAtLength[1] and getPathSegAtLength[2]  
return if there's no path data (or if the path data has no valid segments)?

This topic was discussed on last week's call[3], but no consensus was  
reached.

A testcase[4] shows the following behavior:

Firefox: gPAL throws, gPSAL returns 2**32-1.
Chrome/Opera: gPAL returns SVGPoint(0,0), gPSAL returns 0
IE11: gPAL throws, gPSAL returns 0
For reference, Opera 12 (Presto): gPAL returns SVGPoint(0,0), gPSAL  
returns "undefined"

Proposals:

1a) gPAL should return SVGPoint(NaN, NaN)
1b) gPAL should throw INVALID_ACCESS_ERR (or NOT_SUPPORTED_ERR)
1c) gPAL should return SVGPoint(0,0)

2a) gPSAL shoud throw INVALID_ACCESS_ERR (or NOT_SUPPORTED_ERR)
2b) gPSAL should return 0
2c) gPSAL should return undefined
2d) gPSAL should return MAX_LONG

Please state your opinions in this thread, and feel free to suggest a  
better alternative than the ones listed above.


[1]  
https://svgwg.org/svg2-draft/paths.html#__svg__SVGPathElement__getPointAtLength
[2]  
https://svgwg.org/svg2-draft/paths.html#__svg__SVGPathElement__getPathSegAtLength
[3] http://www.w3.org/2014/06/19-svg-minutes.html#item04
[4] http://jsfiddle.net/hLrtY/

-- 
Erik Dahlstrom, Web Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group

Received on Tuesday, 24 June 2014 13:16:21 UTC