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authorShawn Rutledge <shawn.rutledge@qt.io>2020-08-06 17:28:06 +0200
committerShawn Rutledge <shawn.rutledge@qt.io>2020-08-24 13:50:55 +0200
commit38806273e567a39bd7ca4ced5e6e38dfd7426f27 (patch)
treef2336bf4de830b806903b347238d1c7c6054f3b5 /src/gui/kernel/qevent.cpp
parent0c52e600b3b5c83d128e6b4068d523829357fef0 (diff)
Remove QEventPoint::event() in favor of device()
event()->device() was the most common use case anyway. The idea that the "parent" of a QEventPoint is the QPointerEvent interferes with the ability to copy and move event objects: the parent pointers are dangling unless we use the QPointerEvent subclass destructors to set the points' parents to null. Since there is no move constructor, even returning a QEventPoint from a function by value results in destroying the temporary instance and copying it to the caller's space. So the parent pointer is often useless, unless we do even more work to maintain it when the event moves. If we optimize to avoid copying QEventPoints too much (and perhaps enable exposing _mutable_ points to QML) by storing reusable instances in QPointingDevice (which is the current plan), then the actual parent will no longer be the event. Events are usually stack-allocated, thus temporary and intended to be movable. Change-Id: I24b648dcc046fc79d2401c781f1fda6cb00f47b0 Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Diffstat (limited to 'src/gui/kernel/qevent.cpp')
-rw-r--r--src/gui/kernel/qevent.cpp23
1 files changed, 11 insertions, 12 deletions
diff --git a/src/gui/kernel/qevent.cpp b/src/gui/kernel/qevent.cpp
index df8a18beb0..2414a0d951 100644
--- a/src/gui/kernel/qevent.cpp
+++ b/src/gui/kernel/qevent.cpp
@@ -65,9 +65,7 @@ Q_LOGGING_CATEGORY(lcPointerGrab, "qt.pointer.grab")
static const QString pointDeviceName(const QEventPoint *point)
{
- if (!point->event())
- return {};
- auto device = point->event()->device();
+ const auto device = point->device();
QString deviceName = (device ? device->name() : QLatin1String("null device"));
deviceName.resize(16, u' '); // shorten, and align in case of sequential output
return deviceName;
@@ -228,13 +226,14 @@ QInputEvent::~QInputEvent()
/*!
\internal
- Constructs an invalid event point with the given \a id and \a parent.
+ Constructs an invalid event point with the given \a id and the \a device
+ from which it originated.
This acts as a default constructor in usages like QMap<int, QEventPoint>,
as in qgraphicsscene_p.h.
*/
-QEventPoint::QEventPoint(int id, const QPointerEvent *parent)
- : m_parent(parent), m_pointId(id), m_state(State::Unknown), m_accept(false), m_stationaryWithModifiedProperty(false), m_reserved(0)
+QEventPoint::QEventPoint(int id, const QPointingDevice *device)
+ : m_device(device), m_pointId(id), m_state(State::Unknown), m_accept(false), m_stationaryWithModifiedProperty(false), m_reserved(0)
{
}
@@ -323,7 +322,7 @@ void QEventPoint::clearPassiveGrabbers()
QPointF QEventPoint::normalizedPos() const
{
- auto geom = event()->device()->availableVirtualGeometry();
+ auto geom = m_device->availableVirtualGeometry();
if (geom.isNull())
return QPointF();
return (globalPosition() - geom.topLeft()) / geom.width();
@@ -331,7 +330,7 @@ QPointF QEventPoint::normalizedPos() const
QPointF QEventPoint::startNormalizedPos() const
{
- auto geom = event()->device()->availableVirtualGeometry();
+ auto geom = m_device->availableVirtualGeometry();
if (geom.isNull())
return QPointF();
return (globalPressPosition() - geom.topLeft()) / geom.width();
@@ -339,7 +338,7 @@ QPointF QEventPoint::startNormalizedPos() const
QPointF QEventPoint::lastNormalizedPos() const
{
- auto geom = event()->device()->availableVirtualGeometry();
+ auto geom = m_device->availableVirtualGeometry();
if (geom.isNull())
return QPointF();
return (globalLastPosition() - geom.topLeft()) / geom.width();
@@ -369,7 +368,7 @@ const QPointingDevice *QPointerEvent::pointingDevice() const
QSinglePointEvent::QSinglePointEvent(QEvent::Type type, const QPointingDevice *dev, const QPointF &localPos, const QPointF &scenePos,
const QPointF &globalPos, Qt::MouseButton button, Qt::MouseButtons buttons, Qt::KeyboardModifiers modifiers)
: QPointerEvent(type, dev, modifiers),
- m_point(0, this),
+ m_point(0, dev),
m_button(button),
m_mouseState(buttons),
m_source(Qt::MouseEventNotSynthesized),
@@ -4243,7 +4242,7 @@ QTouchEvent::QTouchEvent(QEvent::Type eventType,
{
for (QEventPoint &point : m_touchPoints) {
m_touchPointStates |= point.state();
- QMutableEventPoint::from(point).setParent(this);
+ QMutableEventPoint::from(point).setDevice(device);
}
}
@@ -4266,7 +4265,7 @@ QTouchEvent::QTouchEvent(QEvent::Type eventType,
m_touchPoints(touchPoints)
{
for (QEventPoint &point : m_touchPoints)
- QMutableEventPoint::from(point).setParent(this);
+ QMutableEventPoint::from(point).setDevice(device);
}
/*!