Allan Sandfeld Jensen, on dim. 03 sept. 2017 19:13:38 +0200, wrote: > On Sonntag, 3. September 2017 18:15:15 CEST Samuel Thibault wrote: > > On the long run, it really should. Just hiding issues is not the way > > forward :) > > > > Also, note that if the performance is so bad, it means something *needs* > > to be fixed, otherwise blind users will get the bad performance, and > > nobody will be there to fix it, because nobody notices it except blind > > users, who are left with little hope to fix it by themselves. > > It is not a issue or a bug. The performance impact comes from sending > everything the mouse hovers over to the accessibility framework (for instance > to be spoken aloud), when there is not any accessibility tools running.
Well, if just moving mouse over windows does send a flurry of events, that's already a bug. There is no need to send all of that to a screen reader, the user won't be able to grasp everything anyway, only not-too-short hovers would be useful (the final destination of the movement, basically). And that's particularly a problem if that makes the interface slow: it's already difficult to use a computer when one has to use a screen reader. If that makes the interface much slower, that's even more difficult, so it is still a bug for that reason. > You are deliberately crippling Qt to always send dbus events even when no one > is listening. That's Qt's fault for not taking care of EventListenerRegistered signals to determine whether someone is listening. > Note the performance impact is the same in all applications regardless of > framework. No. Gtk sends only basic events (application creation notification, basically) when there is no screen reader. > Running accessibility tools has a substantional performance cost on > mouse movements, but a mouse rendered or text scrolling at 60 fps is > completely pointless to blind people, but rather important to everybody else. Sure, but fps is not the only consequence. Responsiveness of the interface is also a consequence. If the performance is really hurt, that's probably because there are too many messages, and so many messages can't be useful for a screen reader either. We do have seen screen readers overflowed with flurries of useless notifications. Really, looking at the whole picture: there are tons of messages needed to get all the tiny movements of the mouse, and render the 60fps. On the other hand, the refresh rates of screen readers are *much* slower. So the message bandwidth needed for it should be much lower. If that's not the case, it means there is spurious information that should be dropped. Samuel
