70795 2011-10-24 19:33:36 -0700 Need to figure out how flexboxes interact with column breaks, page breaks, etc. 2012-08-28 14:06:23 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Unspecified Unspecified NEW P2 Normal --- 62048 1 ojan webkit-unassigned oldest_to_newest 489845 0 ojan 2011-10-24 19:33:36 -0700 http://dev.w3.org/csswg/css3-flexbox/#pagination 706709 1 ojan 2012-08-28 14:06:23 -0700 12:24 PM <TabAtkins> ojan: Yes, there's an entire section in the spec marked as "non-normative" detailing exactly how we think flexbox pagination should work. It's non-normative because we want feedback on it from implementors. ... 12:30 PM <TabAtkins> If the answer ends up being "they're atomic for breaking purposes", that would be sad but acceptable. 12:30 PM <TabAtkins> ojan: Though, what happens when you try to print a webpage laid out using flexbox? 12:30 PM <dhyatt> that's my concern. i doubt anyone even knows. :) 12:30 PM <dhyatt> probably something terrible 12:31 PM <ojan> dhyatt: does CSS pagination and printing use the same logic? 12:34 PM <dhyatt> ojan: all pagination is sharing breaking logic right now 12:34 PM <dhyatt> ojan: what i'm working on now is bringing columns/pages/regions painting and hit testing and that sort of thing even closer together also 12:34 PM <dhyatt> but for the purposes of a layout system like flex box or grid 12:35 PM <dhyatt> "paginating" you don't really have to think about regions/columns/pages 12:35 PM <dhyatt> you just care about "breaks" 12:35 PM <ojan> dhyatt: i see...making sure printing flexboxes works reasonably seems higher priority than CSS columns/pages IMO. i didn't realize it used the same logic. 12:36 PM <dhyatt> really the big thing to know 12:36 PM <dhyatt> is that you want to set your correct block progression position before laying out 12:36 PM <dhyatt> i.e., y position in horizontal text 12:36 PM <dhyatt> if you can't do that 12:36 PM <dhyatt> e.g., because flexing pushes you 12:36 PM <dhyatt> then you have to relayout 12:36 PM <dhyatt> because how you have to paginate may change 12:37 PM <dhyatt> flex boxes are probably very difficult to paginate (like tables) 12:38 PM <dhyatt> well i don't really get how flexing works 12:38 PM <dhyatt> like do you lay out unflexed and paginate? 12:38 PM <dhyatt> and then flex and re-paginate? 12:38 PM <dhyatt> that could get weird 12:38 PM <TabAtkins> dhyatt: Not *quite*. 12:39 PM <TabAtkins> I forget details now, but it tries to be as close to normal flex layout as possible, without being expensive or crazy. 12:40 PM <dhyatt> ojan: well the big thing to know is just that there's a relayout you need to do if your position moves in such a way that pagination has to be redone 12:40 PM <dhyatt> that and try to set the correct position in advance 12:40 PM <dhyatt> since if you do, pagination will just work. 12:40 PM <TabAtkins> And it has substantially different behavior for the four cases of row/column and single-line/multi-line, with multi-line columns being the craziest. 12:41 PM <dhyatt> TabAtkins: well it's cool you wrote something down at least! :) 12:41 PM <ojan> taking a quick look at the spec, i think it tries to set the correct position in advance 12:41 PM <ojan> assuming i understand what you mean by that :) 12:41 PM <dhyatt> yeah i just mean e.g., block layout makes a y-estimation for example 12:42 PM <dhyatt> and tries to lay out at the correct y position 12:42 PM <dhyatt> if it ends up being wrong and has to move 12:42 PM <dhyatt> then it will relayout 12:42 PM <dhyatt> because being paginated requires that 12:42 PM <dhyatt> markForPaginationRelayoutIfNeeded 12:42 PM <dhyatt> is the function that handles it ... 12:44 PM <dhyatt> ojan: i mean, the one thing i'd suggest is we just make sure it doesn't go toes up 12:44 PM <dhyatt> ojan: since crashes would be bad 12:44 PM <ojan> dhyatt: yeah, we should at least add tests showing that we are doing something sane or insane 12:44 PM <dhyatt> for unflexing flex boxes 12:44 PM <dhyatt> as long as you place them as you go 12:44 PM <dhyatt> they should paginate correctly 12:44 PM <ojan> dhyatt: although, i expect our fuzzer would catch most crashes in this area 12:45 PM <dhyatt> for flexing it depends on if you relayout if you flex 12:45 PM <dhyatt> if you do, then they might kinda work too