I filed https://bugs.webkit.org/show_bug.cgi?id=40441
to track this issue. dave ([email protected]) On Jun 10, 2010, at 2:26 PM, David Hyatt wrote: > On Jun 10, 2010, at 1:01 PM, Nathan Vander Wilt wrote: > >> On Jun 9, 2010, at 3:51 PM, David Hyatt wrote: >>> On Jun 9, 2010, at 2:25 AM, Andy Estes wrote: >>> >>>> >>>> On Jun 8, 2010, at 8:34 PM, Nathan Vander Wilt wrote: >>>> >>>>> What Safari 4 seemed to do was simply provide much greater precision, >>>>> where scrolling half a line simply yielded about 20 units instead of >>>>> being ignored. So the above code would yield integral deltas in browsers >>>>> that only fired events in 3-line increments, but nice fractional deltas >>>>> in WebKit. >>>> >>>> Some sites choose to completely ignore wheel deltas less than 120. On >>>> devices like trackpads where a slow but continuous scrolling gesture tends >>>> to result in a series of small, non-cumulative mousewheel events, the old >>>> behavior caused these gestures to be completely ignored. Yahoo! Mail was >>>> one such site where the small fractional values caused compatibility >>>> issues. >>>> >>>>> What Safari 5's WebKit does is turn one "line" into 4800 (!) units >>>>> instead of 40. >>>> >>>> This could be plausible on a trackpad that scales the wheelDelta based on >>>> gesture velocity, although I'd expect a value of 120 for each tick of a >>>> conventional wheel mouse. As Peter said, if you have a test case where >>>> Safari disagrees with IE on Windows or Chrome on either platform, please >>>> file a bug and we'll investigate. >>> >>> Just a guess, but we might have a regression when dealing with the >>> continuous events generated by a MacBook trackpad. >> >> >> >> Thanks, David. I am testing this with my MacBook trackpad (and attached >> Magic Mouse) in Safari 5. >> >> The following demo will need some massaging to work in IE, but shows the >> problem. Scrolling down so "Line 4." is at the top of the page yields a >> deltaSum of -7200 (!). Interpreted according to MSDN documentation >> (http://msdn.microsoft.com/en-us/library/ms536951(VS.85).aspx) this would >> -60 "increments" (which IIRC are 3-line chunks each) and over seven thousand >> pixels according to Quirksmode's interpretation >> (http://www.quirksmode.org/dom/w3c_events.html, grep wheelDelta) of that >> property. Basically, the wheelDelta values are 60 times what they should be. >> >> On Safari 4, the deltaSum ends up at -120 as expected when scrolling down to >> "Line 4", although quite helpfully the sum can be reached gradually when the >> mouse has smooth scrolling. So I would concur that this a regression of some >> sort. >> >> thanks, >> -natevw > > Having investigated the original bug and its fix that caused this regression, > Safari 4's behavior was correct. The new behavior is broken. A tiny > continuous event in Safari 4 correctly reported values that are smaller than > one line delta, because that's exactly what was supposed to happen in terms > of scrolling. > > There are Web sites that depend on never scrolling less than 1 wheel delta > line though. So what can we do to get the best of both worlds? > > Well, the compatibility fix made all of the continuous deltas way larger than > they should be, just to ensure that you never give a value smaller than 120. > That was not the right thing to do. > > If we can't evangelize the Web sites to fix their broken checks, then a > better fix would be to just ensure that the minimum value of a wheel event is > 120, without performing what amounts to "double multiplication" of the > continuous event. This way we only inflate the continuous delta of the small > scrolling gestures. > > Even then, though, we lose some of the magic of continuous scrolling in that > the small gestures aren't supposed to each result in single line movements. > My top preference would be to evangelize the Web sites, but I would settle > for applying the minimum of 1 wheel line (120) to continuous events. The > current behavior is clearly wrong though and needs to be fixed. > > dave > ([email protected]) > > > > _______________________________________________ > webkit-dev mailing list > [email protected] > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev _______________________________________________ webkit-dev mailing list [email protected] http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
