- From: CSS Meeting Bot via GitHub <sysbot+gh@w3.org>
- Date: Mon, 04 Jun 2018 20:57:12 +0000
- To: public-fxtf-archive@w3.org
The Working Group just discussed `stroke-bounding-box and non-scaling-stroke`. <details><summary>The full IRC log of that discussion</summary> <BogdanBrinza> topic: stroke-bounding-box and non-scaling-stroke<br> <BogdanBrinza> GitHub: https://github.com/w3c/fxtf-drafts/issues/279<br> <chris> krit: referencing stroke bbox more now, and this does not take into account non scaling stroke. Is it the bbox or some hueristic of the stroke. We resolved on hueristic in the past to be comparable in all browsers. otherwise result is library dependent.<br> <chris> ... some cannot compute at all, others do not give a tight bbox<br> <AmeliaBR> Current definition/algorithms for the different bounding boxes: https://svgwg.org/svg2-draft/coords.html#BoundingBoxes<br> <chris> ... agreed to use hueristics, more consistent and easier for developers<br> <chris> ... if we keep it we need to clarify effect of NSS<br> <chris> chris: sounds like we should stay with the hueristic<br> <chris> tav: what is the hueristic?<br> <krit> https://drafts.fxtf.org/css-masking-1/#compute-stroke-bounding-box<br> <chris> krit: (looks for link) object bbox and then extending based on stroke properties<br> <chris> AmeliaBR: should check for mitred corners, but should use effective stroke width after NSS<br> <chris> krit: NSS graphical effect so not really geometric<br> <liam> [ https://svgwg.org/svg2-draft/painting.html#TermStrokeShape "Authors should be aware that the shape of a stroke may in some cases, such as at extremely tight curves, differ across platforms." ]<br> <chris> liam: spec says stroke shape may differ across platforms. same in PostScript. depends on precision of floating point.<br> <liam> [hence arguably not testable]<br> <chris> AmeliaBR: also non uniform scales, which mess up the coordinate system for stroke bbox on unscaled stroke<br> <chris> krit: yes, need to do in viewport coordinate space<br> <chris> ... but do we want to, or leave it entirely up to browsers? Affects masking, wll be incosistent<br> <chris> AmeliaBR: should not depend on parent coordinate space. if we integrate NSS then it depends on parent context as well<br> <chris> Tav: authors would not expect things to change with NSS<br> <chris> AmeliaBR: warn authors that using these together will not be useful<br> <chris> Tav: what situation would make them do that<br> <chris> AmeliaBR: like a mask image sized to the drawn area of the shape, then when scaled you expect the mask to scale too but it does not, with NSS<br> <chris> krit: need to specify what happens anyway<br> <chris> AmeliaBR: small intersection of effects, ok to say not supported, but needs a clear warning where they are defined<br> <chris> Tav: ok, good. lets not spend much time, little practical use<br> <chris> AmeliaBR: most important is consistent implementations<br> <chris> liam: and with stroke bounding box. will not be pixel fidelity<br> <chris> krit: give hueristic as a fallback, or say it must be used. in both cases, computing NSS bbox geometrically is not easy<br> <chris> ... prefer to get consistency, so not a tight bbox<br> <chris> chris: i would prefer we exclude it<br> <chris> AmeliaBR: exact computation or a generous hueristic (over rather than under-estimate)<br> <chris> krit: already in the masking spec<br> <chris> AmeliaBR: examples of cases where the mask is a worst case?<br> <chris> krit: will add to the issue<br> <chris> AmeliaBR: would like to see some diagrams. and feedback from other implementors<br> <chris> AmeliaBR: other implementors please give your opinions<br> <chris> BogdanBrinza: Microsoft does not have a strong opinion, but want it to be easy for implementors<br> <chris> krit: differences between the graphics libraries<br> <chris> BogdanBrinza: we don't support NSS yet<br> <chris> krit: this comes up even for ordinary stroke<br> <chris> rrsagent, make minutes<br> <RRSAgent> I have made the request to generate https://www.w3.org/2018/06/04-svg-minutes.html chris<br> <chris> rrsagent, make logs public<br> <RRSAgent> I have made the request, chris<br> <chris> rrsagent, make minutes<br> <RRSAgent> I have made the request to generate https://www.w3.org/2018/06/04-svg-minutes.html chris<br> </details> -- GitHub Notification of comment by css-meeting-bot Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/279#issuecomment-394496816 using your GitHub account
Received on Monday, 4 June 2018 20:57:17 UTC