Refactor pointer event hierarchy

Some goals that have hopefully been achieved are:
- make QPointerEvent and QEventPoint resemble their Qt Quick
  counterparts to such an extent that we can remove those wrappers
  and go back to delivering the original events in Qt Quick
- make QEventPoint much smaller than QTouchEvent::TouchPoint, with no pimpl
- remove most public setters
- reduce the usage of complex constructors that take many arguments
- don't repeat ourselves: move accessors and storage upwards
  rather than having redundant ones in subclasses
- standardize the set of accessors in QPointerEvent
- maintain source compatibility as much as possible: do not require
  modifying event-handling code in any QWidget subclass

To avoid public setters we now introduce a few QMutable* subclasses.
This is a bit like the Builder pattern except that it doesn't involve
constructing a separate disposable object: the main event type can be
cast to the mutable type at any time to enable modifications, iff the
code is linked with gui-private. Therefore event classes can have
less-"complete" constructors, because internal Qt code can use setters
the same way it could use the ones in QTouchEvent before; and the event
classes don't need many friends. Even some read-accessors can be kept
private unless we are sure we want to expose them.

Task-number: QTBUG-46266
Fixes: QTBUG-72173
Change-Id: I740e4e40165b7bc41223d38b200bbc2b403e07b6
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 5 insertions, 6 deletions

diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp
index a3befc4f0a..05bf43d669 100644
--- a/src/widgets/kernel/qwidgetwindow.cpp
+++ b/src/widgets/kernel/qwidgetwindow.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -563,8 +563,7 @@ void QWidgetWindow::handleMouseEvent(QMouseEvent *event)
                 }
             }
 #endif
-            if ((event->type() != QEvent::MouseButtonPress)
-                    || !(event->flags().testFlag(Qt::MouseEventCreatedDoubleClick))) {
+            if ((event->type() != QEvent::MouseButtonPress) || !(QMutableSinglePointEvent::from(event)->isDoubleClick())) {
                 // if the widget that was pressed is gone, then deliver move events without buttons
                 const auto buttons = event->type() == QEvent::MouseMove && qt_popup_down_closed
                                    ? Qt::NoButton : event->buttons();
@@ -666,8 +665,7 @@ void QWidgetWindow::handleMouseEvent(QMouseEvent *event)
     if (!receiver)
         return;
 
-    if ((event->type() != QEvent::MouseButtonPress)
-        || !(event->flags().testFlag(Qt::MouseEventCreatedDoubleClick))) {
+    if ((event->type() != QEvent::MouseButtonPress) || !QMutableSinglePointEvent::from(event)->isDoubleClick()) {
 
         // The preceding statement excludes MouseButtonPress events which caused
         // creation of a MouseButtonDblClick event. QTBUG-25831
@@ -866,7 +864,8 @@ void QWidgetWindow::handleWheelEvent(QWheelEvent *event)
     QPoint mapped = widget->mapFrom(rootWidget, pos);
 
     QWheelEvent translated(QPointF(mapped), event->globalPosition(), event->pixelDelta(), event->angleDelta(),
-                           event->buttons(), event->modifiers(), event->phase(), event->inverted(), event->source());
+                           event->buttons(), event->modifiers(), event->phase(), event->inverted(),
+                           event->source(), event->pointingDevice());
     translated.setTimestamp(event->timestamp());
     QGuiApplication::forwardEvent(widget, &translated, event);
 }