diff options
| -rw-r--r-- | src/widgets/kernel/qapplication.cpp | 76 | ||||
| -rw-r--r-- | src/widgets/kernel/qapplication_p.h | 2 |
2 files changed, 53 insertions, 25 deletions
diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp index b7de0d7a7e..b34380dbc3 100644 --- a/src/widgets/kernel/qapplication.cpp +++ b/src/widgets/kernel/qapplication.cpp @@ -417,7 +417,7 @@ QWidget *QApplicationPrivate::hidden_focus_widget = 0; // will get keyboard inpu QWidget *QApplicationPrivate::active_window = 0; // toplevel with keyboard focus #ifndef QT_NO_WHEELEVENT int QApplicationPrivate::wheel_scroll_lines; // number of lines to scroll -QWidget *QApplicationPrivate::wheel_widget = Q_NULLPTR; +QPointer<QWidget> QApplicationPrivate::wheel_widget; #endif bool qt_in_tab_key_event = false; int qt_antialiasing_threshold = -1; @@ -3326,9 +3326,32 @@ bool QApplication::notify(QObject *receiver, QEvent *e) const bool spontaneous = wheel->spontaneous(); const Qt::ScrollPhase phase = wheel->phase(); - if (phase == Qt::NoScrollPhase || phase == Qt::ScrollBegin - || (phase == Qt::ScrollUpdate && !QApplicationPrivate::wheel_widget)) { - + // Ideally, we should lock on a widget when it starts receiving wheel + // events. This avoids other widgets to start receiving those events + // as the mouse cursor hovers them. However, given the way common + // wheeled mice work, there's no certain way of connecting different + // wheel events as a stream. This results in the NoScrollPhase case, + // where we just send the event from the original receiver and up its + // hierarchy until the event gets accepted. + // + // In the case of more evolved input devices, like Apple's trackpad or + // Magic Mouse, we receive the scroll phase information. This helps us + // connect wheel events as a stream and therefore makes it easier to + // lock on the widget onto which the scrolling was initiated. + // + // We assume that, when supported, the phase cycle follows the pattern: + // + // ScrollBegin (ScrollUpdate* ScrollEnd)+ + // + // This means that we can have scrolling sequences (starting with ScrollBegin) + // or partial sequences (after a ScrollEnd and starting with ScrollUpdate). + // If wheel_widget is null because it was deleted, we also take the same + // code path as an initial sequence. + if (phase == Qt::NoScrollPhase || phase == Qt::ScrollBegin || !QApplicationPrivate::wheel_widget) { + + // A system-generated ScrollBegin event starts a new user scrolling + // sequence, so we reset wheel_widget in case no one accepts the event + // or if we didn't get (or missed) a ScrollEnd previously. if (spontaneous && phase == Qt::ScrollBegin) QApplicationPrivate::wheel_widget = Q_NULLPTR; @@ -3346,7 +3369,10 @@ bool QApplication::notify(QObject *receiver, QEvent *e) res = d->notify_helper(w, &we); eventAccepted = we.isAccepted(); if (res && eventAccepted) { - if (spontaneous && phase != Qt::NoScrollPhase && QGuiApplicationPrivate::scrollNoPhaseAllowed) + // A new scrolling sequence or partial sequence starts and w has accepted + // the event. Therefore, we can set wheel_widget, but only if it's not + // the end of a sequence. + if (spontaneous && (phase == Qt::ScrollBegin || phase == Qt::ScrollUpdate) && QGuiApplicationPrivate::scrollNoPhaseAllowed) QApplicationPrivate::wheel_widget = w; break; } @@ -3357,25 +3383,27 @@ bool QApplication::notify(QObject *receiver, QEvent *e) w = w->parentWidget(); } wheel->setAccepted(eventAccepted); - } else if (QApplicationPrivate::wheel_widget) { - if (!spontaneous) { - // wheel_widget may forward the wheel event to a delegate widget, - // either directly or indirectly (e.g. QAbstractScrollArea will - // forward to its QScrollBars through viewportEvent()). In that - // case, the event will not be spontaneous but synthesized, so - // we can send it straigth to the receiver. - d->notify_helper(w, wheel); - } else { - const QPoint &relpos = QApplicationPrivate::wheel_widget->mapFromGlobal(wheel->globalPos()); - QWheelEvent we(relpos, wheel->globalPos(), wheel->pixelDelta(), wheel->angleDelta(), wheel->delta(), wheel->orientation(), wheel->buttons(), - wheel->modifiers(), wheel->phase(), wheel->source()); - we.spont = true; - we.ignore(); - d->notify_helper(QApplicationPrivate::wheel_widget, &we); - wheel->setAccepted(we.isAccepted()); - if (phase == Qt::ScrollEnd) - QApplicationPrivate::wheel_widget = Q_NULLPTR; - } + } else if (!spontaneous) { + // wheel_widget may forward the wheel event to a delegate widget, + // either directly or indirectly (e.g. QAbstractScrollArea will + // forward to its QScrollBars through viewportEvent()). In that + // case, the event will not be spontaneous but synthesized, so + // we can send it straight to the receiver. + d->notify_helper(w, wheel); + } else { + // The phase is either ScrollUpdate or ScrollEnd, and wheel_widget + // is set. Since it accepted the wheel event previously, we continue + // sending those events until we get a ScrollEnd, which signifies + // the end of the natural scrolling sequence. + const QPoint &relpos = QApplicationPrivate::wheel_widget->mapFromGlobal(wheel->globalPos()); + QWheelEvent we(relpos, wheel->globalPos(), wheel->pixelDelta(), wheel->angleDelta(), wheel->delta(), wheel->orientation(), wheel->buttons(), + wheel->modifiers(), wheel->phase(), wheel->source()); + we.spont = true; + we.ignore(); + d->notify_helper(QApplicationPrivate::wheel_widget, &we); + wheel->setAccepted(we.isAccepted()); + if (phase == Qt::ScrollEnd) + QApplicationPrivate::wheel_widget = Q_NULLPTR; } } break; diff --git a/src/widgets/kernel/qapplication_p.h b/src/widgets/kernel/qapplication_p.h index 832d37a329..4b3cf773dc 100644 --- a/src/widgets/kernel/qapplication_p.h +++ b/src/widgets/kernel/qapplication_p.h @@ -202,7 +202,7 @@ public: static QWidget *active_window; #ifndef QT_NO_WHEELEVENT static int wheel_scroll_lines; - static QWidget *wheel_widget; + static QPointer<QWidget> wheel_widget; #endif static int enabledAnimations; // Combination of QPlatformTheme::UiEffect |