Add HoverHandler to detect a hovering mouse pointer

Detect whether the handler's parent contains the mouse, while the
point property tracks the event point (position etc.)

Task-number: QTBUG-68072
Change-Id: Ica99332596eab3e344852a11f1ceb7aaf6348c86
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

11 files changed, 443 insertions, 5 deletions

diff --git a/src/quick/handlers/handlers.pri b/src/quick/handlers/handlers.pri
index a47d144fbb..111a526ce2 100644
--- a/src/quick/handlers/handlers.pri
+++ b/src/quick/handlers/handlers.pri
@@ -2,6 +2,7 @@ HEADERS += \
     $$PWD/qquickdraghandler_p.h \
     $$PWD/qquickhandlerpoint_p.h \
     $$PWD/qquickhandlersmodule_p.h \
+    $$PWD/qquickhoverhandler_p.h \
     $$PWD/qquickmultipointhandler_p.h \
     $$PWD/qquickpinchhandler_p.h \
     $$PWD/qquickpointerdevicehandler_p.h \
@@ -17,6 +18,7 @@ SOURCES += \
     $$PWD/qquickdraghandler.cpp \
     $$PWD/qquickhandlerpoint.cpp \
     $$PWD/qquickhandlersmodule.cpp \
+    $$PWD/qquickhoverhandler.cpp \
     $$PWD/qquickmultipointhandler.cpp \
     $$PWD/qquickpinchhandler.cpp \
     $$PWD/qquickpointerdevicehandler.cpp \
diff --git a/src/quick/handlers/qquickhandlersmodule.cpp b/src/quick/handlers/qquickhandlersmodule.cpp
index c9e08fe4f2..814602c0bd 100644
--- a/src/quick/handlers/qquickhandlersmodule.cpp
+++ b/src/quick/handlers/qquickhandlersmodule.cpp
@@ -40,6 +40,7 @@
 #include "qquickhandlersmodule_p.h"
 #include "qquickpointerhandler_p.h"
 #include "qquickdraghandler_p.h"
+#include "qquickhoverhandler_p.h"
 #include "qquickpinchhandler_p.h"
 #include "qquickpointhandler_p.h"
 #include "qquicktaphandler_p.h"
@@ -87,6 +88,7 @@ static void qt_quickhandlers_defineModule(const char *uri, int major, int minor)
     qmlRegisterType<QQuickDragHandler>(uri,major,minor,"DragHandler");
     qmlRegisterUncreatableType<QQuickDragAxis>(uri, major, minor, "DragAxis",
         QQuickDragHandler::tr("DragAxis is only available as a grouped property of DragHandler"));
+    qmlRegisterType<QQuickHoverHandler>(uri,major,minor,"HoverHandler");
     qmlRegisterType<QQuickPinchHandler>(uri,major,minor,"PinchHandler");
     qmlRegisterType<QQuickTapHandler>(uri,major,minor,"TapHandler");
     qRegisterMetaType<QQuickHandlerPoint>();
diff --git a/src/quick/handlers/qquickhoverhandler.cpp b/src/quick/handlers/qquickhoverhandler.cpp
new file mode 100644
index 0000000000..430722bd93
--- /dev/null
+++ b/src/quick/handlers/qquickhoverhandler.cpp
@@ -0,0 +1,107 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qquickhoverhandler_p.h"
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(lcHoverHandler, "qt.quick.handler.hover")
+
+/*!
+    \qmltype HoverHandler
+    \instantiates QQuickHoverHandler
+    \inqmlmodule QtQuick
+    \ingroup qtquick-handlers
+    \brief Handler for mouse and tablet hover
+
+    HoverHandler detects a hovering cursor.  Since touchscreens don't generally
+    offer hover events, in practice it detects a hovering mouse or tablet stylus.
+
+    \sa MouseArea
+*/
+
+QQuickHoverHandler::QQuickHoverHandler(QObject *parent)
+    : QQuickSinglePointHandler(parent)
+    , m_hovered(false)
+{
+    // Rule out the touchscreen for now (can be overridden in QML in case a hover-detecting touchscreen exists)
+    setAcceptedDevices(static_cast<QQuickPointerDevice::DeviceType>(
+        static_cast<int>(QQuickPointerDevice::AllDevices) ^ static_cast<int>(QQuickPointerDevice::TouchScreen)));
+}
+
+QQuickHoverHandler::~QQuickHoverHandler()
+{
+    QQuickItemPrivate *parItemPrivate = QQuickItemPrivate::get(parentItem());
+    parItemPrivate->setHasHoverInChild(false);
+}
+
+void QQuickHoverHandler::componentComplete()
+{
+    parentItem()->setAcceptHoverEvents(true);
+    QQuickItemPrivate::get(parentItem())->setHasHoverInChild(true);
+}
+
+bool QQuickHoverHandler::wantsPointerEvent(QQuickPointerEvent *event)
+{
+    QQuickEventPoint *point = event->point(0);
+    if (QQuickPointerDeviceHandler::wantsPointerEvent(event) && wantsEventPoint(point)) {
+        // assume this is a mouse event, so there's only one point
+        setPointId(point->pointId());
+        return true;
+    }
+    setHovered(false);
+    return false;
+}
+
+void QQuickHoverHandler::handleEventPoint(QQuickEventPoint *point)
+{
+    setHovered(true);
+    setPassiveGrab(point);
+}
+
+void QQuickHoverHandler::setHovered(bool hovered)
+{
+    if (m_hovered != hovered) {
+        qCDebug(lcHoverHandler) << objectName() << "hovered" << m_hovered << "->" << hovered;
+        m_hovered = hovered;
+        emit hoveredChanged();
+    }
+}
+
+QT_END_NAMESPACE
diff --git a/src/quick/handlers/qquickhoverhandler_p.h b/src/quick/handlers/qquickhoverhandler_p.h
new file mode 100644
index 0000000000..876d01761b
--- /dev/null
+++ b/src/quick/handlers/qquickhoverhandler_p.h
@@ -0,0 +1,91 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QQUICKHOVERHANDLER_H
+#define QQUICKHOVERHANDLER_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qquickitem.h"
+#include "qevent.h"
+#include "qquicksinglepointhandler_p.h"
+#include <QtCore/qbasictimer.h>
+
+QT_BEGIN_NAMESPACE
+
+class Q_AUTOTEST_EXPORT QQuickHoverHandler : public QQuickSinglePointHandler
+{
+    Q_OBJECT
+    Q_PROPERTY(bool hovered READ isHovered NOTIFY hoveredChanged)
+
+public:
+    explicit QQuickHoverHandler(QObject *parent = 0);
+    ~QQuickHoverHandler();
+
+    bool isHovered() const { return m_hovered; }
+
+Q_SIGNALS:
+    void hoveredChanged();
+
+protected:
+    void componentComplete() override;
+    bool wantsPointerEvent(QQuickPointerEvent *event) override;
+    void handleEventPoint(QQuickEventPoint *point) override;
+
+private:
+    void setHovered(bool hovered);
+
+private:
+    bool m_hovered;
+};
+
+QT_END_NAMESPACE
+
+QML_DECLARE_TYPE(QQuickHoverHandler)
+
+#endif // QQUICKHOVERHANDLER_H
diff --git a/src/quick/handlers/qquickpointerhandler.cpp b/src/quick/handlers/qquickpointerhandler.cpp
index 4539aa221c..33c2acebe2 100644
--- a/src/quick/handlers/qquickpointerhandler.cpp
+++ b/src/quick/handlers/qquickpointerhandler.cpp
@@ -310,9 +310,15 @@ QPointF QQuickPointerHandler::eventPos(const QQuickEventPoint *point) const
 
 bool QQuickPointerHandler::parentContains(const QQuickEventPoint *point) const
 {
-    if (point) {
-        if (QQuickItem *par = parentItem())
-            return par->contains(par->mapFromScene(point->scenePosition()));
+    if (!point)
+        return false;
+    if (QQuickItem *par = parentItem()) {
+        if (par->window()) {
+            QPoint screenPosition = par->window()->mapToGlobal(point->scenePosition().toPoint());
+            if (!par->window()->geometry().contains(screenPosition))
+                return false;
+        }
+        return par->contains(par->mapFromScene(point->scenePosition()));
     }
     return false;
 }
diff --git a/src/quick/handlers/qquicksinglepointhandler.cpp b/src/quick/handlers/qquicksinglepointhandler.cpp
index 04b4214bab..84f8349a53 100644
--- a/src/quick/handlers/qquicksinglepointhandler.cpp
+++ b/src/quick/handlers/qquicksinglepointhandler.cpp
@@ -120,7 +120,7 @@ bool QQuickSinglePointHandler::wantsPointerEvent(QQuickPointerEvent *event)
             }
         }
         if (chosen && candidatePointCount == 1) {
-            m_pointInfo.m_id = chosen->pointId();
+            setPointId(chosen->pointId());
             chosen->setAccepted();
         }
     }
@@ -185,6 +185,11 @@ void QQuickSinglePointHandler::moveTarget(QPointF pos, QQuickEventPoint *point)
     m_pointInfo.m_position = target()->mapFromScene(m_pointInfo.m_scenePosition);
 }
 
+void QQuickSinglePointHandler::setPointId(int id)
+{
+    m_pointInfo.m_id = id;
+}
+
 /*!
     \qmlproperty int QtQuick::SinglePointHandler::acceptedButtons
 
diff --git a/src/quick/handlers/qquicksinglepointhandler_p.h b/src/quick/handlers/qquicksinglepointhandler_p.h
index 66ef1dbeb2..79bf74b222 100644
--- a/src/quick/handlers/qquicksinglepointhandler_p.h
+++ b/src/quick/handlers/qquicksinglepointhandler_p.h
@@ -87,6 +87,8 @@ protected:
 
     void moveTarget(QPointF pos, QQuickEventPoint *point);
 
+    void setPointId(int id);
+
 private:
     void reset();
 
diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index 01413385d9..3b1402fe16 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -67,6 +67,7 @@
 #include <QtQuick/private/qquickstate_p.h>
 #include <private/qquickitem_p.h>
 #include <QtQuick/private/qquickaccessibleattached_p.h>
+#include <QtQuick/private/qquickhoverhandler_p.h>
 #include <QtQuick/private/qquickpointerhandler_p.h>
 
 #include <private/qv4engine_p.h>
@@ -7342,6 +7343,8 @@ void QQuickItemPrivate::setHasHoverInChild(bool hasHover)
             QQuickItemPrivate *otherChildPrivate = QQuickItemPrivate::get(otherChild);
             if (otherChildPrivate->subtreeHoverEnabled || otherChildPrivate->hoverEnabled)
                 return; // nope! sorry, something else wants it kept on.
+            if (otherChildPrivate->hasHoverHandlers())
+                return; // nope! sorry, we have pointer handlers which are interested.
         }
     }
 
@@ -8095,6 +8098,16 @@ bool QQuickItemPrivate::hasPointerHandlers() const
     return extra.isAllocated() && !extra->pointerHandlers.isEmpty();
 }
 
+bool QQuickItemPrivate::hasHoverHandlers() const
+{
+    if (!hasPointerHandlers())
+        return false;
+    for (QQuickPointerHandler *h : extra->pointerHandlers)
+        if (qmlobject_cast<QQuickHoverHandler *>(h))
+            return true;
+    return false;
+}
+
 #if QT_CONFIG(quick_shadereffect)
 QQuickItemLayer::QQuickItemLayer(QQuickItem *item)
     : m_item(item)
diff --git a/src/quick/items/qquickitem_p.h b/src/quick/items/qquickitem_p.h
index 93287cf0aa..f43f04ed39 100644
--- a/src/quick/items/qquickitem_p.h
+++ b/src/quick/items/qquickitem_p.h
@@ -280,6 +280,7 @@ public:
     QQuickItemLayer *layer() const;
 
     bool hasPointerHandlers() const;
+    bool hasHoverHandlers() const;
 
     // data property
     static void data_append(QQmlListProperty<QObject> *, QObject *);
diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index c80e052dad..e53ca7f8de 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -46,6 +46,7 @@
 #include "qquickevents_p_p.h"
 
 #include <private/qquickdrag_p.h>
+#include <private/qquickhoverhandler_p.h>
 #include <private/qquickpointerhandler_p.h>
 
 #include <QtQuick/private/qsgrenderer_p.h>
@@ -1546,8 +1547,20 @@ bool QQuickWindowPrivate::clearHover(ulong timestamp)
     QPointF pos = q->mapFromGlobal(QGuiApplicationPrivate::lastCursorPosition.toPoint());
 
     bool accepted = false;
-    for (QQuickItem* item : qAsConst(hoverItems))
+    for (QQuickItem* item : qAsConst(hoverItems)) {
         accepted = sendHoverEvent(QEvent::HoverLeave, item, pos, pos, QGuiApplication::keyboardModifiers(), timestamp, true) || accepted;
+        QQuickItemPrivate *itemPrivate = QQuickItemPrivate::get(item);
+        if (itemPrivate->hasPointerHandlers()) {
+            pos = q->mapFromGlobal(QCursor::pos());
+            QQuickPointerEvent *pointerEvent = pointerEventInstance(QQuickPointerDevice::genericMouseDevice(), QEvent::MouseMove);
+            pointerEvent->point(0)->reset(Qt::TouchPointMoved, pos, quint64(1) << 24 /* mouse has device ID 1 */, timestamp, QVector2D());
+            pointerEvent->point(0)->setAccepted(true);
+            pointerEvent->localize(item);
+            for (QQuickPointerHandler *h : itemPrivate->extra->pointerHandlers)
+                if (QQuickHoverHandler *hh = qmlobject_cast<QQuickHoverHandler *>(h))
+                    hh->handlePointerEvent(pointerEvent);
+        }
+    }
     hoverItems.clear();
     return accepted;
 }
@@ -1843,6 +1856,16 @@ bool QQuickWindowPrivate::deliverHoverEvent(QQuickItem *item, const QPointF &sce
         }
     }
 
+    if (itemPrivate->hasPointerHandlers()) {
+        QQuickPointerEvent *pointerEvent = pointerEventInstance(QQuickPointerDevice::genericMouseDevice(), QEvent::MouseMove);
+        pointerEvent->point(0)->reset(Qt::TouchPointMoved, scenePos, quint64(1) << 24 /* mouse has device ID 1 */, timestamp, QVector2D());
+        pointerEvent->point(0)->setAccepted(true);
+        pointerEvent->localize(item);
+        for (QQuickPointerHandler *h : itemPrivate->extra->pointerHandlers)
+            if (QQuickHoverHandler *hh = qmlobject_cast<QQuickHoverHandler *>(h))
+                hh->handlePointerEvent(pointerEvent);
+    }
+
     if (itemPrivate->hoverEnabled) {
         QPointF p = item->mapFromScene(scenePos);
         if (item->contains(p)) {
diff --git a/tests/manual/pointer/sidebar.qml b/tests/manual/pointer/sidebar.qml
new file mode 100644
index 0000000000..ce2c770592
--- /dev/null
+++ b/tests/manual/pointer/sidebar.qml
@@ -0,0 +1,186 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the manual tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.12
+import Qt.labs.handlers 1.0
+import "content"
+
+Rectangle {
+    id: root
+    width: 640
+    height: 480
+    color: "#444"
+
+    Component {
+        id: buttonsAndStuff
+        Column {
+            anchors.fill: parent
+            anchors.margins: 8
+            spacing: 8
+
+            Rectangle {
+                objectName: "buttonWithMA"
+                width: parent.width
+                height: 30
+                color: buttonMA.pressed ? "lightsteelblue" : "#999"
+                border.color: buttonMA.containsMouse ? "cyan" : "transparent"
+
+                MouseArea {
+                    id: buttonMA
+                    objectName: "buttonMA"
+                    hoverEnabled: true
+                    anchors.fill: parent
+                    onClicked: console.log("clicked MA")
+                }
+
+                Text {
+                    anchors.centerIn: parent
+                    text: "MouseArea"
+                }
+            }
+
+            Rectangle {
+                objectName: "buttonWithHH"
+                width: parent.width
+                height: 30
+                color: flash ? "#999" : "white"
+                border.color: buttonHH.hovered ? "cyan" : "transparent"
+                property bool flash: true
+
+                HoverHandler {
+                    id: buttonHH
+                    objectName: "buttonHH"
+                    acceptedDevices: PointerDevice.AllDevices
+                }
+
+                TapHandler {
+                    onTapped: tapFlash.start()
+                }
+
+                Text {
+                    anchors.centerIn: parent
+                    text: "HoverHandler"
+                }
+
+                FlashAnimation on flash {
+                    id: tapFlash
+                }
+            }
+        }
+    }
+
+    Rectangle {
+        id: paddle
+        width: 100
+        height: 40
+        color: paddleHH.hovered ? "indianred" : "#888"
+        y: parent.height - 100
+        radius: 10
+
+        HoverHandler {
+            id: paddleHH
+            objectName: "paddleHH"
+        }
+
+        SequentialAnimation on x {
+            NumberAnimation {
+                to: root.width - paddle.width
+                duration: 2000
+                easing { type: Easing.InOutQuad }
+            }
+            PauseAnimation { duration: 100 }
+            NumberAnimation {
+                to: 0
+                duration: 2000
+                easing { type: Easing.InOutQuad }
+            }
+            PauseAnimation { duration: 100 }
+            loops: Animation.Infinite
+        }
+    }
+
+    Rectangle {
+        objectName: "topSidebar"
+        radius: 5
+        antialiasing: true
+        x: -radius
+        y: -radius
+        width: 120
+        height: 200
+        border.color: topSidebarHH.hovered ? "cyan" : "black"
+        color: "#777"
+
+        Rectangle {
+            color: "cyan"
+            width: 10
+            height: width
+            radius: width / 2
+            visible: topSidebarHH.hovered
+            x: topSidebarHH.point.position.x - width / 2
+            y: topSidebarHH.point.position.y - height / 2
+            z: 100
+        }
+
+        HoverHandler {
+            id: topSidebarHH
+            objectName: "topSidebarHH"
+        }
+
+        Loader {
+            objectName: "topSidebarLoader"
+            sourceComponent: buttonsAndStuff
+            anchors.fill: parent
+        }
+    }
+
+    Rectangle {
+        objectName: "bottomSidebar"
+        radius: 5
+        antialiasing: true
+        x: -radius
+        anchors.bottom: parent.bottom
+        anchors.bottomMargin: -radius
+        width: 120
+        height: 200
+        border.color: bottomSidebarMA.containsMouse ? "cyan" : "black"
+        color: "#777"
+
+        MouseArea {
+            id: bottomSidebarMA
+            objectName: "bottomSidebarMA"
+            hoverEnabled: true
+            anchors.fill: parent
+        }
+
+        Loader {
+            objectName: "bottomSidebarLoader"
+            sourceComponent: buttonsAndStuff
+            anchors.fill: parent
+        }
+    }
+}