> On Sept. 23, 2014, 3:01 nachm., Thomas Lübking wrote: > > Qt cannot "distiguish" because there's nothing to distinguish - the driver > > generates synthetic wheel event for the inertia. > > You can btw. turn that <censored> off. > > > > Seems an issue with inertial scrolling on X11 as well > > https://bugs.freedesktop.org/show_bug.cgi?id=38909 > > Otherwise i'd have opted for "the driver shall please stop this when you > > hit a key". > > > > On a random note, I can't find that setting in systemsettings? > > If there's a config GUI for this, aligning to it seems reasonable, BUT does > > no way fix the actual issue w/ inertia (ie. "you don't have control over > > your input device") > > René J.V. Bertin wrote: > You may not believe it, but I actually prefer the UE with the feature on. > Probably because it saves me some movements, which is always good (less RSI). > > Yes, I imagine that the issue can occur on Linux as well if inertial > scrolling works the same way there. It just never bit me on Linux - and yet I > run that on underpowered machines ... > Might be a thought to define the modifier key to get wheelMouseZooms in > that case, or at least make that possible somewhere in systemsettings? > > You're right, I haven't been able to find the setting in systemsettings. > The setting *is* part of the standard settings, though, no idea why it > slipped through and remained a hidden setting. But because it's part of the > standard settings I went with aligning to it, instead of hacking in a new > switch as in Konsole. > NB, seems likely that Konsole offers its own switch because the authors > didn't go the length I did to find out about the one in `kdeglobalrc`? > > Thomas Lübking wrote: > UX isn't my concern - but doing that in the driver is simply idiotic. > (Sorry, but hey - Peter H. shares that opinion ;-) > What eg. happens when you reached the end of the document? The driver > keeps scrolling and you don't even notice that. > > Either the view provides inertic scrolling or you purchase a rodant that > can alter between swing and precise wheel (w/o trying to advertise here, eg. > Logitech M500 is an affordable device with this capability) > > Choosing another modifier won't help, but at best move the problem around > (ok, there's no META key on OSX, but it is indeed used for shortcuts on > linux/windows - often global ones. So instead of scaling the text, you end up > scaling the entire desktop ;-) > > While I personally don't use text scaling in kate (this way), if there's > no present UI for the global config, it can hardly be used and we can't (?) > introduce config GUI for the kate part in SC4, I assume (kate devs will know > better) > Also simply disabling a feature because it is *one* occasion of a driver > issue doesn't sound too reasonable - what if I'd in general like to scale the > text this way but am still annoyed by the driver behavior? > > One way to deal with this is to measure the time between the last > unmodified wheel event and the now modified wheel event. If that is too low > to be reasonably caused by a human being (ie. the scroll "started" unmodified > and suddenly a modifier kicks in) one could ignore the modifier. > That would however have to apply to all items. > Stupid question: how does (Qt)WebKit behave (eg. in qt-assistant?) in > this regard? > > René J.V. Bertin wrote: > I use Apple's Magic Trackpad, no spamming intended, but I wouldn't want > to change for anything else anymore... > > > ok, there's no META key on OSX > > There is. META is mapped to Ctrl by default on OS X (and CTRL to Command, > which is the real Meta key), but there is a setting to switch that back. I > presume the default is conceived to reflect the fact that OS X uses the > Command key in place of Ctrl for shortcuts. It apparently never occurred to > them to define a special code (`ACCEL`) for the standard accelerator "opcode" > ;) > > > Also simply disabling a feature because it is one occasion of a driver > issue doesn't sound too reasonable > > How do you think I found the global setting and how to read it out? It's > used exactly this way in KTextEdit (see `KTextEdit::wheelEvent`) which again > raises the question why the setting isn't exposed in systemsettings. > > > - what if I'd in general like to scale the text this way but am still > annoyed by the driver behavior? > > The only solution in that case would be to configure the feature to use > another key or key combination, one that works for you and your workflow and > doesn't risk to get triggered unexpectedly. > > > Stupid question: how does (Qt)WebKit behave (eg. in qt-assistant?) in > this regard? > > Not so stupid: Qt does exactly the same thing, and it doesn't appear to > be optional in any way there. This is probably why `KTextEdit` overrides the > `wheelEvent` it inherits from the parent Qt widget. > > René J.V. Bertin wrote: > BTW: > > What eg. happens when you reached the end of the document? The driver > keeps scrolling and you don't even notice that. > > But the view knows. On iOS and newer OS X versions it actually bounces > when this happens. Which is why I learned that I prefer the inertial > scrolling, because I tried switching it off to get rid of the bouncing and > felt like handicapped. > > BTW, the OS X driver's inertial feature can be stopped very easily: swipe > to get the view to scroll; place back 2 fingers and the scrolling stops at > once. Exactly as it did with the big thumb trackball I had before. > > Dominik Haumann wrote: > Did you reach any consensus about this patch? If this is not going in, it > should be discarded. > > René J.V. Bertin wrote: > Good question, I guess that we both forgot about the whole thing ... > Thomas? > > Thomas Lübking wrote: > I still oppose the idea to try to fix this in client code. > > a) the setting is KDE4/support only, ie. deprecated code anyway > b) there's apparently no config GUI for that setting?! > => secret workaround > c) You suggested that (all?) Qt5 applications suffer from this problem > (where we cannot even involve this solution -> problem globally remains. Let > alone gtk+ etc. clients) > d) The setting can no more be used to prevent eg. accelerated scrolling > (which it originally selected) > e) There may be random custom handling of modifiers on wheel events > everywhere - and they all needed to be stripped/made configurable at least. > > > Let alone that faking scroll inertia in the server is silly itfp. > > a) The server must either simply stop faking inertia with the next > keyboard/crossing event (while apparently that's not simple on evdev) or > (rather) scrolling inertia has to be done in the client (w/o faking input > events) > b) Eg. when I scroll and move the mouse to another window or just > scrollview while the inertia faking is going on, I suddenly scroll the other > window/view? (the view is not "fixable" on serverside inertia faking) > c) Do I really want scrolling inertia on the destkop to change virtual > desktops? > > René J.V. Bertin wrote: > a) yay, stable release code that actually allows you to get some work > done without fearing whatever tomorrow's update might break. Fixing naggles > in KDE4 is like showing love to unknown hordes of users who stick with LTS or > non-Linux distributions for good reasons. > b) So? If that's really a serious issue for you (you know what vi[m] is, > right? :P) then there's always the possibility to add a setting to Kate that > is first-time initialised off the global setting and then maintained > independently. > c) I haven't checked with Qt5 for this since I created the RR, nor KF5 > applications so I don't know to what extent my claim still stands, nor why > the proposed fix wouldn't work there. (I'd hope there's something comparable, > in fact, I seem to recall that Qt also has a "should the mouse wheel zoom" > setting.) But we're talking about a KDE4 application here in which the issue > is particularly noticeable (to me). KDE. 4. Not GTk or anything else. > d) eh? The setting I use is called `KGlobalSettings::wheelMouseZooms()`. > I don't see what that has got to do with accelerated scrolling, nor how > checking the setting prevents that kind of scrolling? > e) again, so? This is a patch for Kate. It's not intented to cure all > pain in the world, but it could show how this issue can be tackled to others > who're bothered by it in a random other application. > > a) I don't agree and also think neither of us gets to dictate what the > server may not or must do. Besides ... what server, on platforms that don't > use X11? > b) I don't know what happens to you, but in my case on OS X this is not > possible because the inertial scrolling stops as soon as I move the pointer. > It does not when I press or release a key, and I think that's rightly so. I > could in fact find a use for such an event in Kate (like the accelerated > scrolling you mentioned). > c) ditto. (In fact, you actually want to disable virtual desktop change > coupled to mouse *movement* that's not part of a multi-touch gesture, trust > me ;)) > > Thomas Lübking wrote: > a) and will see maybe one more release - at best. > b) this typically means "my secret pet feature workaround with no use for > anyone else" - if it's so important, it must be exposed to the common user. > c) kdeglobals is gone (ok, deprecated to kdelibs support) and this > setting isn't invoked by any QPA - what you set here has no whatsoever impact > on plain Qt5 applications. > d) look up the code, the comment describes the history of the feature. > e) this means you seriously want to fix clients one-by-one by stripping > features instead of simply addressing to core culprit? > > -- > > a) I don't dictate, but merely state sane behavior. If OSX btw. fakes > this through a common input lib, it could just as well fix it there (despite > the feature belongs into the clients) > b) I frankly would have to try, but then the solution is simple: slightly > move the mouse before pressing a modifier... > c) what "ditto"? if i'm above the desktop and rotate the wheel by > one/two/three iteration/s, I expect to end up one/two/three desktops ahead, > not 13 or 25. I'm talking about a mouse wheel, not a touch device (which > isn't controllable itr. anyway) > > > You may have a point though in that altering the font scale (or anything > like that) is of no use from a touch device, because it can/does not generate > clean wheel clicks. > However, the proper™ solution is then to base this behavior on the nature > of the input device and/or eg. ignore scroll events for such behavior when > many™ of them occur in short™ time. > Not some obscure and deprecated setting that you luckily happen to know. > > René J.V. Bertin wrote: > I've got better things to do than keep up a tit-for-tat dialogue, but I > do not agree that simulating inertial scrolling is anything but the "event > server's" business. That's not any less the case than that it's some server's > role to provide access to any other kind of events, or fonts. > What's more, that event server probably has access to lower-level > information from the input device anyway, and can use that information to > determine whether simulation is needed or not (a trackball wouldn't require > it). And above all, it can provide the simulated events in a consistent > manner across all clients. > > But I'm not going to insist ... nor feel inclined to discard this request > because there's only been feedback from a single person who has failed to > come up with (AFAIC) convincingly valid arguments against my change. > > Thomas Lübking wrote: > > that event server probably has access to lower-level information from > the input device anyway > > Which it can (and does) easily pass downstream while it completely lacks > (by nature) private client detail informations. > > > it can provide the simulated events in a consistent manner across all > clients > > What apparently leads to glitches. > > You however completely ignored any technical issues - and suggestions. > Reading across https://bugs.freedesktop.org/show_bug.cgi?id=38909 again, > it seems the faked events have a higher valuator (scrollDistance) than usual. > If that's the same on OSX, it could be used (next to an absurd frequency?) to > control the feature. > > Relying on a deprecated and hidden config key is no solution at all - I'm > sorry if that doesn't convince you. > > René J.V. Bertin wrote: > I've been ignoring technical issues mostly because they are moot, but I > do realise I could have made it clearer that this whole thing concerns OS X > primarily. It's not that the issue cannot be reproduced on X11/xcb set-ups, I > just don't run into it. > > I have not been able to reproduce the issue with Qt 5.4.2 on OS X which > somehow manages to dissociate keypresses and simulated inertial scrolling. > So the patch proposed here is only a fix for Kate 4.14 and most likely > not required for newer Qt5-based versions. It brings Kate's behaviour in > synch with applications that are based on KTextEdit, like all KDE PIM > applications, by using the same config key (cf `KTextBrowser::wheelEvent` and > `KTextEdit::wheelEvent`). In my world that makes a perfectly fine fix for a > branch that is no longer under active development. I don't see a valid reason > to make it OS X only though; if you mentioned things that are definitely > broken because of it I missed them. > > There's a valid point that could have been made is that my patch should > do as the wheelEvent handlers cited above, that is provide an `else` for when > `wheelMouseZooms()` returns false. Maybe that was implied; if so it wasn't > explicit enough. I'll look into that possibility, off the top of my head I'd > say that might actually reinstate the accelerated scrolling referred to above > (which I think is impossible to obtain in Kate's current implementation). > > Thomas Lübking wrote: > Did you check whether you can make QTextBrowser from Qt5 zoom text at all > - for this doesn't work here. > Have not checked why, but > > float delta = e->angleDelta().y() / 120.f; > zoomInF(delta); > > looks very suspicious, since 120.0 is the typical delta for one wheel > event... > > Therefore i'm not convinced this problem would not re-popup on kate/5 and > KTextBrowser is a deprecated thin wrapper around QTextBrowser. It's in > kdelibs4support, so using the deprecated key *there* is ok, but only > schedules the problem in kate. > > In case that's not clear: I give a shit on what happens to kate/4, I just > want to ensure that we get an actual solution to this problem that has a > lifetime beyond next month. > > The core problem as I perceive it: > 1. some devices/systems fake input events to provide inertial scrolling > 2. touch devices to not generate precise wheel clicks > > Leaving completely aside what me or the evdev maintainer thinks about one > or the other cause, I assume in neither case anything like font scaling > should ever happen for such imprecise input, right? > > => Can we detect this kind of input and prevent unwanted action? > > Possible detection vectors: > a) higher valuator (suggested to apply for X11, but you must check on OSX) > b) many events in short time (eg. it's fair to assume that users would > first check the result of a font size change?) > c) suddenly modified event after a very short time since the last > unmodified event (related to b) > > If we can detect the "unwanted" (modified) input, we can avoid the > undesired action, agree? > And this will neither be a KDE/4 only solution, nor require invocation of > inaccessible config keys nor re-tie kate with kdelibs4support, correct? Do > you agre such solution would be favorable to this approach? > > René J.V. Bertin wrote: > Text zoom works for me in Qt5's Assistant, and in a Qt5 build of xxdiff > on OS X and X11/xcb, as well as in Kate/5 using Qt 5.3.2 on Linux. > I have raised the issue on Qt's development ML, with the hope that I can > find a fix to backport to Qt4 on OS X, which I now think would be the best > solution (again, it would seem that Qt5-based applications aren't affected by > this issue on OS X). Hopefully this will also raise some awareness to the > issue on X11/xcb . > The issue is actually worse under X11 in the sense that the coasting > continues after the view reached the top or bottom, whereas on OS X simulated > inertial scrolling is implemented really well and determined by the kind of > widget the events are sent to. > > >The core problem as I perceive it: > > > >1. some devices/systems fake input events to provide inertial scrolling > > It is not on OS X (and possibly MS Windows) because Qt 5.4 clearly > demonstrates that it is somehow possible to handle the simulated events > separately from the keypress events: press the Meta (Command) key while the > view is coast-scrolling, and it will keep scrolling. Press the same key > during an active, "real" scroll, and zooming ensues. Apparently I will have > to start looking at `- (void)scrollWheel:(NSEvent *)theEvent` in qnsview.mm > (cocoa platform plugin). > >2. touch devices to not generate precise wheel clicks > > This may be true on X11/xcb (where I only ever encountered imprecise > trackpads with all kinds of unwanted side-effects), but not on OS X. 2-finger > scrolling causes text views to scroll by the number of lines set with "mouse > wheel scrolls by". It is not necessarily easy to move your 2 fingers the > distance that corresponds to exactly 1 such click, but that's an operator > limitation, not by definition a device limitation. > > I don't really understand your detection vector, but the main hurdle I > have is that ATM I can only do rather limited KF5 *testing* on Linux, no > development on any platform. Qt5 is a different matter (cocoa and xcb > platform plugins both on OS X). > > Thomas Lübking wrote: > Qt assistant is QWebKit, xxfiff has a custom textview/zoom implementation > and kate as well, non of them is a QTextBrowser, ie. what KTextBrowser would > behave like. > > > whereas on OS X simulated inertial scrolling is implemented really well > and determined by the kind of widget the events are sent to. > > Either OS X exposes client side widget types to the input (faking) server > or (i'd say: rather) Qt5 actually just performs client side inertial > scrolling (and makes the system aware of that to not fake anything for this > window) - Qt does know that you've a touch input device (on any backend; > touch events are different from and only translated to wheel events) > > > > It is not necessarily easy to move your 2 fingers the distance that > corresponds to exactly 1 such click > > That is actually what I meant by "touch devices do not generate precise > wheel clicks"; changing the font size 1 or 2 steps up or down should be an > obstacle game - no matter of the system. Isn't for you? (And if it's for any > operator, it's not an operator problem, touchpads scroll-by-slide is just > hardly controllable) > > The detection can be performed by a plain Qt application, I'll write a > test case tonight. > > René J.V. Bertin wrote: > > Either OS X exposes client side widget types to the input (faking) > server > > or (i'd say: rather) Qt5 actually just performs client side inertial > scrolling > > I'm pretty damn sure it's neither (or maybe a special case of the 1st > option). The system provides a basic widget/class called `NSView` that just > about any widget that provides a view on content descends from, and that > widget already knows how to scroll. Clients typically have to concern > themselves only with preparing the content for display in those NSViews, not > with how to scroll them. It clearly is configurable because not all clients > show the bouncing behaviour when scrolling hits the top or bottom, but AFAIK > the basic operation is handled by the system. > > Oh, and I checked since I'm typing this in Chrome where "wheel scrolling" > doesn't happen on a line-by-line basis: I'm getting what looks like single > pixel scrolling precision from my trackpad. You do have a point though: > there's imprecision in that it isn't perfectly clear how far you have to > slide your finger tips to scroll 1 line or N pixel(s). > > René J.V. Bertin wrote: > Another thought, independent of where inertial scrolling should be > implemented and what kind of fix is implemented ultimately against text > zooming during scroll coasting: > > KDE4 provides a global config parameter that controls whether or not the > mouse wheel should zoom text. Applications (Kate included) should take that > setting into account, or provide their own switch to override the global > setting (and/or compensate for the fact there is no UI to set the global > switch). > > Thomas Lübking wrote: > "KDE4" has seen it's last release last December and I'm not sure any more > releases are scheduled. > Kate is based upon KF/5 since the Applications 14.12 release (last > december...) and does not require kdelibs4support. > > You can of course do whatever you want downstream, but I severely doubt > there'll be some KDE SC4 kate release in the future. > > => If you spot a problem (and it exists in KF/5 - mind that you maybe > want to use kate on linux as well ;-) you should seek to fix it for KF/5 > and/or in a way that covers both versions. > > René J.V. Bertin wrote: > Again, it's not like nobody is still using KDE4, or even that we are a > dwindling minority (and as long as even Kubuntu doesn't manage to provide a > stable KF5-based version where everything works as it does under KDE4 I can > only agree with anyone deciding not to switch). > IMVHO it doesn't matter whether there will still be official releases; > fixes can be committed in git, from where they can be picked up by (LTS) > distro maintainers.
If you desperately want to face the same problems again next year (at least on non-OSX or touchpads(?), got to try inertia emulation on evdev) instead of addressing them once and for all, just go for it. *shrug* As long as you understood the conditions, discussion about this aspect is pointless, I will very likely not understand the stance anyway (to my mind, it's completely absurd, sorry) You're however not introducing a bug, so the patch itself is fine to me. I just don't think it's a viable solution to the problem. - Thomas ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://git.reviewboard.kde.org/r/120319/#review67302 ----------------------------------------------------------- On Sept. 3, 2015, 6:03 nachm., René J.V. Bertin wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://git.reviewboard.kde.org/r/120319/ > ----------------------------------------------------------- > > (Updated Sept. 3, 2015, 6:03 nachm.) > > > Review request for Kate, KDE Software on Mac OS X and kdelibs. > > > Repository: kate > > > Description > ------- > > KDE has a global text editor option that can be used to let Ctrl-MouseWheel > events zoom the text font being used. Kate does not respect this setting, > which is an omission that can lead to unexpected behaviour. > > On OS X, the feature works slightly differently in the sense that > `Qt::ControlModifier` does not designate the control key, but the command (?, > Apple) key. In addition, Qt's event handling does not appear to be able to > distinguish between scrolling under direct control, and residual scroll > movement that's due to simulated inertia. As a result, any attempt to use a > keyboard shortcut while a text view has not stopped moving completely will > lead to text zooming. > See https://bugreports.qt-project.org/browse/QTBUG-41475 . > > At first I thought to replace `Qt::ControlModifier` with `Qt::MetaModifier` > on OS X but that would probably require changes in many locations, and thus > best be preceded by a design decision if the standard shortcut modifier key > ought not be referenced via a symbolic platform constant not named after a > specific key, instead of being hardcoded (and using a key name). > > Therefore, I present a small patch that checks > `KGlobalSettings::wheelMouseZooms()` when the platform's `ControlModifier` is > held and a wheel event received. > > An alternative solution could introduce a Kate-specific setting (just like > Konsole has one), but that would require far more changes. > > > Diffs > ----- > > part/view/kateviewinternal.cpp a2906f3 > > Diff: https://git.reviewboard.kde.org/r/120319/diff/ > > > Testing > ------- > > On OS X against kdelibs 4.14.1 (git/kde4). The change consists of an > additional call to a standard kdelibs function which I do not expect to > introduce regressions on any platform. > > I looked at kate's git/master code, which lacks a `wheelEvent` handler > suggesting the feature works differently there. However, Qt 5.3.1 > applications (like Digia's own Qt Creator) still suffer from the phenomenon > described above, so a fix would be beneficial for KF5 too) > > > File Attachments > ---------------- > > Qt4 patch to prevent unwanted/unexpected text zoom while scrolling > > https://git.reviewboard.kde.org/media/uploaded/files/2015/09/03/ae8f63f3-4289-40bb-8b97-61a934bb33ec__patch-avoid-unwanted-fontzooming.diff > > > Thanks, > > René J.V. Bertin > >
