08:16:55 RRSAgent has joined #svg 08:16:55 logging to http://www.w3.org/2014/08/25-svg-irc 08:16:58 Chair: Cameron 08:17:01 Agenda: https://www.w3.org/Graphics/SVG/WG/wiki/F2F/London_2014/Agenda 08:17:10 Meeting: London 2014 SVG WG F2F Day 3 08:19:54 jun has joined #svg 08:20:35 Rossen_ has joined #svg 08:20:37 scribeNick: ed 08:21:01 topic: Performance of transformation in panning & zooming ("transforms", "will-change") 08:22:06 https://www.w3.org/Graphics/SVG/WG/wiki/Proposals/Performance_in_panning_%26_zooming 08:23:24 konno: zooming and panning is for general webpages rather than mapping 08:23:32 ... it's an important feature 08:23:39 ... we have three requirements 08:23:49 ... 1) smooth start 08:24:01 ... 2) smooth transition during panning and zooming 08:24:15 ... 3) crisp view after panning/zooming is finished 08:24:36 ... there are some issues re the performance of zooming & panning 08:24:43 ... see table in the above wikipage 08:24:57 krit: is this scripted or native implementation? 08:25:08 brian: it's scripted, it's not the whole page 08:25:08 jun has joined #svg 08:25:14 ... with translate3d 08:25:27 rossen: so how are you doing this exactly? 08:25:39 brian: by chaning the transform, so doesn't affect the whole page 08:26:12 konno: [presents the table https://www.w3.org/Graphics/SVG/WG/wiki/Proposals/Performance_in_panning_%26_zooming#Facts] 08:26:46 s/translate3d/scale3d 08:27:26 ... [demos the first example running in firefox] 08:30:01 Tav has joined #svg 08:30:03 ... shows the last example in chrome, where chrome doesn't render the view crisply after finishing the zooming 08:30:29 (this is chrome version 36) 08:30:41 https://www.w3.org/Graphics/SVG/WG/wiki/Proposals/Performance_in_panning_%26_zooming#Facts 08:32:05 heycam: maybe 2d scale transform might work better, does it have the same behaviour then? 08:33:05 konno: possible solutions, specifying css transform more closely 08:33:17 https://www.w3.org/Graphics/SVG/WG/wiki/Proposals/Performance_in_panning_%26_zooming#Possible_Solutions 08:33:40 ... it might also be included in the will-change spec 08:33:56 ... third way is using another way for zoming and panning, maybe using compositor thread 08:34:16 ... it's a little bit difficult currently 08:34:24 ... but this is an implementation issue, not a spec issue 08:34:58 ... should this be a spec issue or a implementation issue? 08:35:09 krit: that everything is pixelated is an implementation issue 08:35:23 heycam: css transform prob doesn't say anything about crisp rendering 08:35:36 Rossen_: you're talking about zooming and panning, but are using transforms 08:35:46 ... these are different things 08:36:08 ... they can do similar things, but you can do different optimizations for the zooming and panning than for transforms 08:36:28 ... depending on the current environment it will cause degenerate cases 08:36:35 ... causing other elements to be rendered as well 08:36:47 ... in the context of p&z, the two are completely different 08:37:00 ... so, are you talking about p&z or about transforms? 08:37:09 heycam: it's implemented using transforms 08:37:19 ... because that's what you have to do currently 08:38:12 Rossen_: in trident we have optimized p&z 08:38:24 krit: you don't mean svg panning and zooming, right? 08:38:35 Rossen_: right, not specifically svg panning and zooming 08:38:48 brian: it's for an element, not for the whole page 08:39:03 ... the question about spec vs impl 08:39:14 ... the gecko behavior should be fixed in impl 08:39:31 ... when we scale using css animation, we don't resample during animation, so that it's smooth 08:39:42 ... we could adjust heuristics 08:39:52 ... don't think we need to spec anything for that 08:39:58 heycam: i think I agree 08:40:14 tav: are tehre cases where you'd want a different behaviour? 08:40:21 heycam: jerky zooming? 08:40:37 Rossen_: in host zooming, we don't resample until you reach a stable state 08:41:12 brian: we had some heuristics for layers and animation 08:41:23 Rossen_: it's certainly an implementation issue 08:42:05 konno: if it's an impl issue, we should create a testsuite for this 08:42:11 brian: sure, but it shouldn't be a conformance testsuite 08:42:20 ... just something to link to from the bugs filed 08:42:34 Rossen_: or submit the tests to the performance WG 08:42:45 heycam: for like rendering perf? 08:43:08 Rossen_: yes, I think it'd be good to ping them to see if they have any ideas on this 08:43:39 jet has joined #svg 08:43:43 heycam: for the second issue, about chrome and not rendering crisply, if you use 2d scale instead 08:44:17 krit: for some reason it looked the same (in webkit) 08:44:34 ... the start and end should always look crisp 08:44:39 heycam: so you think it's a bug? 08:44:59 krit: it's using scale3d as the last argument, which shouldn't be hw acc 08:45:07 Rossen_: have you tried this with text instead? 08:45:17 ... so without svg, just regular html 08:45:28 konno: only with svg 08:45:35 krit: it's using an object tag 08:46:09 ed: would be interesting to see if it's the same when using ,