MouseProxy

main.qml

import QtQuick 2.6
import QtQuick.Layouts 1.0
import Qt.labs.controls 1.0
import QtQuick.Layouts 1.3
import MouseProxy 0.1

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    Row {
        spacing: 10
        padding: 10
        Button {
            width: 200
            text: "Yo"
            MouseProxy.target: loButton
        }
        Button {
            id: loButton
            text: "Lo"
        }
    }
}

mouseproxyattached.cpp

#include "mouseproxyattached.h"
#include <QMouseEvent>
#include <QHoverEvent>
#include <QDebug>
#include <QToolTip>

MouseProxyAttached::MouseProxyAttached(QObject* parent) : QObject(parent)
{
    if (parent)
    {
        parent->installEventFilter(this);
        m_item = qobject_cast<QQuickItem*>(parent);
        m_item->setAcceptHoverEvents(true);
    }
}

MouseProxyAttached* MouseProxyAttached::qmlAttachedProperties(QObject *object)
{
    return new MouseProxyAttached(object);
}

QQuickItem* MouseProxyAttached::target() const
{
    return m_target;
}

void MouseProxyAttached::setTarget(QQuickItem *target)
{
    if (m_target == target)
        return;

    m_target = target;
    emit targetChanged(target);
}

bool MouseProxyAttached::eventFilter(QObject *obj, QEvent *event)
{
    //() << event;
    if (QMouseEvent* mouseEvent = dynamic_cast<QMouseEvent*>(event))
    {
        QPointF sourceLocalPos = mouseEvent->localPos();
        QPointF mappedLocalPos(sourceLocalPos.x()*m_target->width()/m_item->width(),
                               sourceLocalPos.y()*m_target->height()/m_item->height());
        QMouseEvent* mappedEvent = new QMouseEvent(
                    event->type(),
                    mappedLocalPos,
                    m_item->mapToItem(m_target, mouseEvent->windowPos()),
                    m_item->mapToItem(m_target, mouseEvent->screenPos()),
                    mouseEvent->button(),
                    mouseEvent->buttons(),
                    mouseEvent->modifiers(),
                    mouseEvent->source());
        QCoreApplication::postEvent(m_target, mappedEvent);
    }
    if (event->type() == QEvent::HoverEnter)
    {
        QHoverEvent* hoverEvent = static_cast<QHoverEvent*>(event);
        //QToolTip::showText(m_item->mapToGlobal(hoverEvent->pos()).toPoint(), "Tooltip\n:)");
    }
    if (event->type() == QEvent::HoverLeave)
    {
        //QToolTip::hideText();
    }

    return false;
}


void registerMouseProxyAttachedType()
{
    qmlRegisterUncreatableType<MouseProxyAttached>("MouseProxy", 0, 1, "MouseProxy", "");
}

Q_COREAPP_STARTUP_FUNCTION(registerMouseProxyAttachedType)

mouseproxyattached.h

#ifndef MOUSEPROXYATTACHED_H
#define MOUSEPROXYATTACHED_H

#include <QObject>
#include <QQuickItem>
#include <QtQml>
class MouseProxyAttached : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QQuickItem* target READ target WRITE setTarget NOTIFY targetChanged)

public:
    MouseProxyAttached(QObject* parent = 0);
    static MouseProxyAttached* qmlAttachedProperties(QObject *object);
    QQuickItem* target() const;
    void setTarget(QQuickItem* target);

protected:
      bool eventFilter(QObject *obj, QEvent *event);

signals:
    void targetChanged(QQuickItem* target);

private:
    QQuickItem* m_item = nullptr;
    QQuickItem* m_target = nullptr;
};

QML_DECLARE_TYPEINFO(MouseProxyAttached, QML_HAS_ATTACHED_PROPERTIES)

#endif // MOUSEPROXYATTACHED_H