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-rw-r--r--src/quick/items/qquickflickable.cpp97
1 files changed, 67 insertions, 30 deletions
diff --git a/src/quick/items/qquickflickable.cpp b/src/quick/items/qquickflickable.cpp
index e12e85db64..7bf242a527 100644
--- a/src/quick/items/qquickflickable.cpp
+++ b/src/quick/items/qquickflickable.cpp
@@ -62,6 +62,8 @@
QT_BEGIN_NAMESPACE
Q_DECLARE_LOGGING_CATEGORY(lcHandlerParent)
+Q_LOGGING_CATEGORY(lcVel, "qt.quick.flickable.velocity")
+Q_LOGGING_CATEGORY(lcWheel, "qt.quick.flickable.wheel")
// FlickThreshold determines how far the "mouse" must have moved
// before we perform a flick.
@@ -263,7 +265,8 @@ QQuickFlickablePrivate::QQuickFlickablePrivate()
, deceleration(QML_FLICK_DEFAULTDECELERATION)
, maxVelocity(QML_FLICK_DEFAULTMAXVELOCITY), reportedVelocitySmoothing(100)
, delayedPressEvent(nullptr), pressDelay(0), fixupDuration(400)
- , flickBoost(1.0), fixupMode(Normal), vTime(0), visibleArea(nullptr)
+ , flickBoost(1.0), initialWheelFlickDistance(qApp->styleHints()->wheelScrollLines() * 24)
+ , fixupMode(Normal), vTime(0), visibleArea(nullptr)
, flickableDirection(QQuickFlickable::AutoFlickDirection)
, boundsBehavior(QQuickFlickable::DragAndOvershootBounds)
, boundsMovement(QQuickFlickable::FollowBoundsBehavior)
@@ -531,10 +534,14 @@ void QQuickFlickablePrivate::updateBeginningEnd()
if (atBeginning != vData.atBeginning) {
vData.atBeginning = atBeginning;
atYBeginningChange = true;
+ if (!vData.moving && atBeginning)
+ vData.smoothVelocity.setValue(0);
}
if (atEnd != vData.atEnd) {
vData.atEnd = atEnd;
atYEndChange = true;
+ if (!vData.moving && atEnd)
+ vData.smoothVelocity.setValue(0);
}
// Horizontal
@@ -547,10 +554,14 @@ void QQuickFlickablePrivate::updateBeginningEnd()
if (atBeginning != hData.atBeginning) {
hData.atBeginning = atBeginning;
atXBeginningChange = true;
+ if (!hData.moving && atBeginning)
+ hData.smoothVelocity.setValue(0);
}
if (atEnd != hData.atEnd) {
hData.atEnd = atEnd;
atXEndChange = true;
+ if (!hData.moving && atEnd)
+ hData.smoothVelocity.setValue(0);
}
if (vData.extentsChanged) {
@@ -1489,6 +1500,7 @@ void QQuickFlickable::wheelEvent(QWheelEvent *event)
d->hData.velocity = 0;
d->timer.start();
d->maybeBeginDrag(currentTimestamp, event->position());
+ d->lastPosTime = -1;
break;
case Qt::NoScrollPhase: // default phase with an ordinary wheel mouse
case Qt::ScrollUpdate:
@@ -1515,20 +1527,34 @@ void QQuickFlickable::wheelEvent(QWheelEvent *event)
return;
}
+ qreal elapsed = qreal(currentTimestamp - d->lastPosTime) / qreal(1000);
+ if (elapsed <= 0) {
+ d->lastPosTime = currentTimestamp;
+ qCDebug(lcWheel) << "insufficient elapsed time: can't calculate velocity" << elapsed;
+ return;
+ }
+
if (event->source() == Qt::MouseEventNotSynthesized || event->pixelDelta().isNull()) {
- // physical mouse wheel, so use angleDelta
+ // no pixel delta (physical mouse wheel, or "dumb" touchpad), so use angleDelta
int xDelta = event->angleDelta().x();
int yDelta = event->angleDelta().y();
+ // For a single "clicky" wheel event (angleDelta +/- 120),
+ // we want flick() to end up moving a distance proportional to QStyleHints::wheelScrollLines().
+ // The decel algo from there is
+ // qreal dist = v2 / (accel * 2.0);
+ // i.e. initialWheelFlickDistance = (120 / dt)^2 / (deceleration * 2)
+ // now solve for dt:
+ // dt = 120 / sqrt(deceleration * 2 * initialWheelFlickDistance)
+ if (!isMoving())
+ elapsed = 120 / qSqrt(d->deceleration * 2 * d->initialWheelFlickDistance);
if (yflick() && yDelta != 0) {
- bool valid = false;
- if (yDelta > 0 && contentY() > -minYExtent()) {
- d->vData.velocity = qMax(yDelta*2 - d->vData.smoothVelocity.value(), qreal(d->maxVelocity/4));
- valid = true;
- } else if (yDelta < 0 && contentY() < -maxYExtent()) {
- d->vData.velocity = qMin(yDelta*2 - d->vData.smoothVelocity.value(), qreal(-d->maxVelocity/4));
- valid = true;
- }
- if (valid) {
+ qreal instVelocity = yDelta / elapsed;
+ // if the direction has changed, start over with filtering, to allow instant movement in the opposite direction
+ if ((instVelocity < 0 && d->vData.velocity > 0) || (instVelocity > 0 && d->vData.velocity < 0))
+ d->vData.velocityBuffer.clear();
+ d->vData.addVelocitySample(instVelocity, d->maxVelocity);
+ d->vData.updateVelocity();
+ if ((yDelta > 0 && contentY() > -minYExtent()) || (yDelta < 0 && contentY() < -maxYExtent())) {
d->flickY(d->vData.velocity);
d->flickingStarted(false, true);
if (d->vData.flicking) {
@@ -1539,15 +1565,13 @@ void QQuickFlickable::wheelEvent(QWheelEvent *event)
}
}
if (xflick() && xDelta != 0) {
- bool valid = false;
- if (xDelta > 0 && contentX() > -minXExtent()) {
- d->hData.velocity = qMax(xDelta*2 - d->hData.smoothVelocity.value(), qreal(d->maxVelocity/4));
- valid = true;
- } else if (xDelta < 0 && contentX() < -maxXExtent()) {
- d->hData.velocity = qMin(xDelta*2 - d->hData.smoothVelocity.value(), qreal(-d->maxVelocity/4));
- valid = true;
- }
- if (valid) {
+ qreal instVelocity = xDelta / elapsed;
+ // if the direction has changed, start over with filtering, to allow instant movement in the opposite direction
+ if ((instVelocity < 0 && d->hData.velocity > 0) || (instVelocity > 0 && d->hData.velocity < 0))
+ d->hData.velocityBuffer.clear();
+ d->hData.addVelocitySample(instVelocity, d->maxVelocity);
+ d->hData.updateVelocity();
+ if ((xDelta > 0 && contentX() > -minXExtent()) || (xDelta < 0 && contentX() < -maxXExtent())) {
d->flickX(d->hData.velocity);
d->flickingStarted(true, false);
if (d->hData.flicking) {
@@ -1562,18 +1586,13 @@ void QQuickFlickable::wheelEvent(QWheelEvent *event)
int xDelta = event->pixelDelta().x();
int yDelta = event->pixelDelta().y();
- qreal elapsed = qreal(currentTimestamp - d->lastPosTime) / 1000.;
- if (elapsed <= 0) {
- d->lastPosTime = currentTimestamp;
- return;
- }
QVector2D velocity(xDelta / elapsed, yDelta / elapsed);
- d->lastPosTime = currentTimestamp;
d->accumulatedWheelPixelDelta += QVector2D(event->pixelDelta());
d->drag(currentTimestamp, event->type(), event->position(), d->accumulatedWheelPixelDelta,
true, !d->scrollingPhase, true, velocity);
event->accept();
}
+ d->lastPosTime = currentTimestamp;
if (!event->isAccepted())
QQuickItem::wheelEvent(event);
@@ -1744,6 +1763,10 @@ void QQuickFlickable::componentComplete()
setContentX(-minXExtent());
if (!d->vData.explicitValue && d->vData.startMargin != 0.)
setContentY(-minYExtent());
+ if (lcWheel().isDebugEnabled() || lcVel().isDebugEnabled()) {
+ d->timeline.setObjectName(QLatin1String("timeline for Flickable ") + objectName());
+ d->velocityTimeline.setObjectName(QLatin1String("velocity timeline for Flickable ") + objectName());
+ }
}
void QQuickFlickable::viewportMoved(Qt::Orientations orient)
@@ -2504,9 +2527,23 @@ void QQuickFlickable::setMaximumFlickVelocity(qreal v)
/*!
\qmlproperty real QtQuick::Flickable::flickDeceleration
- This property holds the rate at which a flick will decelerate.
-
- The default value is platform dependent.
+ This property holds the rate at which a flick will decelerate:
+ the higher the number, the faster it slows down when the user stops
+ flicking via touch, touchpad or mouse wheel. For example 0.0001 is nearly
+ "frictionless", and 10000 feels quite "sticky".
+
+ The default value is platform dependent. Values of zero or less are not allowed.
+
+ \note For touchpad flicking, some platforms drive Flickable directly by
+ sending QWheelEvents with QWheelEvent::phase() being \c Qt::ScrollMomentum,
+ after the user has released all fingers from the touchpad. In that case,
+ the operating system is controlling the deceleration, and this property has
+ no effect.
+
+ \note For mouse wheel scrolling, and for gesture scrolling on touchpads
+ that do not have a momentum phase, extremely large values of
+ flickDeceleration can make Flickable very resistant to scrolling,
+ especially if \l maximumFlickVelocity is too small.
*/
qreal QQuickFlickable::flickDeceleration() const
{
@@ -2519,7 +2556,7 @@ void QQuickFlickable::setFlickDeceleration(qreal deceleration)
Q_D(QQuickFlickable);
if (deceleration == d->deceleration)
return;
- d->deceleration = deceleration;
+ d->deceleration = qMax(0.001, deceleration);
emit flickDecelerationChanged();
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-03 21:02:29 +0000