tdf#125517 Qt5 implement a minimal Qt5ObjectWindow

Since we can't use an input and visual transparent widget, like a
GtkGrid, we have to implement input forwarding in the QWindow.

Using a Qt5Widget directly results in other problems on Qt 5.12+,
like these warnings (depending on the tested Qt::WA_* flags):
* Attempted flush to non-raster surface QWidgetWindow(0xa386c10,
name="QWidgetClassWindow") of type QSurface::OpenGLSurface
(consider using Qt::WA_PaintOnScreen to exclude from
backingstore sync)
* QWidget::paintEngine: Should no longer be called

So the current QWidget::createWindowContainer has to stay and key
and mouse handling must be implemented as in Qt5Widget. And the
QWindow is strangely not accessible through the windowHandle() of
the container QWwidget.

As a result this patch is mostly boilerplate code, publishing the
Qt5Widget mouse and key handling as static functions.

Change-Id: I5be5f5fa1379c6bdefab0f96604251801c252b38
Reviewed-on: https://gerrit.libreoffice.org/73566
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

3 files changed, 72 insertions, 29 deletions

diff --git a/vcl/qt5/Qt5Object.cxx b/vcl/qt5/Qt5Object.cxx
index a635a5931886..12d8b39a52ae 100644
--- a/vcl/qt5/Qt5Object.cxx
+++ b/vcl/qt5/Qt5Object.cxx
@@ -21,10 +21,9 @@
 #include <Qt5Object.moc>
 
 #include <Qt5Frame.hxx>
+#include <Qt5Widget.hxx>
 
-#include <QtWidgets/QWidget>
 #include <QtGui/QGuiApplication>
-#include <QtGui/QWindow>
 
 Qt5Object::Qt5Object(Qt5Frame* pParent, bool bShow)
     : m_pParent(pParent)
@@ -34,8 +33,9 @@ Qt5Object::Qt5Object(Qt5Frame* pParent, bool bShow)
     if (!m_pParent || !pParent->GetQWidget())
         return;
 
-    m_pQWindow = new QWindow;
+    m_pQWindow = new Qt5ObjectWindow(*this);
     m_pQWidget = QWidget::createWindowContainer(m_pQWindow, pParent->GetQWidget());
+    m_pQWidget->setAttribute(Qt::WA_NoSystemBackground);
 
     if (bShow)
         m_pQWidget->show();
@@ -103,4 +103,33 @@ void Qt5Object::Show(bool bVisible)
 
 void Qt5Object::SetForwardKey(bool /*bEnable*/) {}
 
+Qt5ObjectWindow::Qt5ObjectWindow(Qt5Object& rParent)
+    : m_rParent(rParent)
+{
+    assert(m_rParent.frame() && m_rParent.frame()->GetQWidget());
+}
+
+void Qt5ObjectWindow::mousePressEvent(QMouseEvent* pEvent)
+{
+    m_rParent.CallCallback(SalObjEvent::ToTop);
+    Qt5Widget::handleMousePressEvent(*m_rParent.frame(), pEvent);
+}
+
+void Qt5ObjectWindow::mouseReleaseEvent(QMouseEvent* pEvent)
+{
+    Qt5Widget::handleMouseReleaseEvent(*m_rParent.frame(), pEvent);
+}
+
+bool Qt5ObjectWindow::event(QEvent* pEvent)
+{
+    return Qt5Widget::handleEvent(*m_rParent.frame(), *m_rParent.widget(), pEvent)
+           || QWindow::event(pEvent);
+}
+
+void Qt5ObjectWindow::keyReleaseEvent(QKeyEvent* pEvent)
+{
+    if (!Qt5Widget::handleKeyReleaseEvent(*m_rParent.frame(), *m_rParent.widget(), pEvent))
+        QWindow::keyReleaseEvent(pEvent);
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/qt5/Qt5OpenGLContext.cxx b/vcl/qt5/Qt5OpenGLContext.cxx
index 6f095e7cc857..a33f7abde2f5 100644
--- a/vcl/qt5/Qt5OpenGLContext.cxx
+++ b/vcl/qt5/Qt5OpenGLContext.cxx
@@ -147,5 +147,6 @@ void Qt5OpenGLContext::initWindow()
         InitChildWindow(m_pChildWindow.get());
     }
 
-    m_pWindow = static_cast<Qt5Object*>(m_pChildWindow->ImplGetWindowImpl()->mpSysObj)->m_pQWindow;
+    m_pWindow
+        = static_cast<Qt5Object*>(m_pChildWindow->ImplGetWindowImpl()->mpSysObj)->windowHandle();
 }
diff --git a/vcl/qt5/Qt5Widget.cxx b/vcl/qt5/Qt5Widget.cxx
index 27ce382cb349..b46b48b35366 100644
--- a/vcl/qt5/Qt5Widget.cxx
+++ b/vcl/qt5/Qt5Widget.cxx
@@ -120,7 +120,8 @@ void Qt5Widget::resizeEvent(QResizeEvent* pEvent)
     m_rFrame.CallCallback(SalEvent::Resize, nullptr);
 }
 
-void Qt5Widget::handleMouseButtonEvent(QMouseEvent* pEvent, bool bReleased)
+void Qt5Widget::handleMouseButtonEvent(const Qt5Frame& rFrame, QMouseEvent* pEvent,
+                                       const ButtonKeyState eState)
 {
     SalMouseEvent aEvent;
     switch (pEvent->button())
@@ -144,16 +145,19 @@ void Qt5Widget::handleMouseButtonEvent(QMouseEvent* pEvent, bool bReleased)
     aEvent.mnCode = GetKeyModCode(pEvent->modifiers()) | GetMouseModCode(pEvent->buttons());
 
     SalEvent nEventType;
-    if (bReleased)
-        nEventType = SalEvent::MouseButtonUp;
-    else
+    if (eState == ButtonKeyState::Pressed)
         nEventType = SalEvent::MouseButtonDown;
-    m_rFrame.CallCallback(nEventType, &aEvent);
+    else
+        nEventType = SalEvent::MouseButtonUp;
+    rFrame.CallCallback(nEventType, &aEvent);
 }
 
-void Qt5Widget::mousePressEvent(QMouseEvent* pEvent) { handleMouseButtonEvent(pEvent, false); }
+void Qt5Widget::mousePressEvent(QMouseEvent* pEvent) { handleMousePressEvent(m_rFrame, pEvent); }
 
-void Qt5Widget::mouseReleaseEvent(QMouseEvent* pEvent) { handleMouseButtonEvent(pEvent, true); }
+void Qt5Widget::mouseReleaseEvent(QMouseEvent* pEvent)
+{
+    handleMouseReleaseEvent(m_rFrame, pEvent);
+}
 
 void Qt5Widget::mouseMoveEvent(QMouseEvent* pEvent)
 {
@@ -405,7 +409,7 @@ static sal_uInt16 GetKeyCode(int keyval, Qt::KeyboardModifiers modifiers)
     return nCode;
 }
 
-void Qt5Widget::commitText(const QString& aText) const
+void Qt5Widget::commitText(Qt5Frame& rFrame, const QString& aText)
 {
     SalExtTextInputEvent aInputEvent;
     aInputEvent.mpTextAttr = nullptr;
@@ -414,19 +418,21 @@ void Qt5Widget::commitText(const QString& aText) const
     aInputEvent.mnCursorPos = aInputEvent.maText.getLength();
 
     SolarMutexGuard aGuard;
-    vcl::DeletionListener aDel(&m_rFrame);
-    m_rFrame.CallCallback(SalEvent::ExtTextInput, &aInputEvent);
+    vcl::DeletionListener aDel(&rFrame);
+    rFrame.CallCallback(SalEvent::ExtTextInput, &aInputEvent);
     if (!aDel.isDeleted())
-        m_rFrame.CallCallback(SalEvent::EndExtTextInput, nullptr);
+        rFrame.CallCallback(SalEvent::EndExtTextInput, nullptr);
 }
 
-bool Qt5Widget::handleKeyEvent(QKeyEvent* pEvent, bool bDown)
+bool Qt5Widget::handleKeyEvent(Qt5Frame& rFrame, const QWidget& rWidget, QKeyEvent* pEvent,
+                               const ButtonKeyState eState)
 {
     sal_uInt16 nCode = GetKeyCode(pEvent->key(), pEvent->modifiers());
-    if (bDown && nCode == 0 && !pEvent->text().isEmpty()
-        && testAttribute(Qt::WA_InputMethodEnabled))
+    if (eState == ButtonKeyState::Pressed && nCode == 0 && !pEvent->text().isEmpty()
+        && rWidget.testAttribute(Qt::WA_InputMethodEnabled))
     {
-        commitText(pEvent->text());
+        commitText(rFrame, pEvent->text());
+        pEvent->accept();
         return true;
     }
 
@@ -439,14 +445,16 @@ bool Qt5Widget::handleKeyEvent(QKeyEvent* pEvent, bool bDown)
     QGuiApplication::inputMethod()->update(Qt::ImCursorRectangle);
 
     bool bStopProcessingKey;
-    if (bDown)
-        bStopProcessingKey = m_rFrame.CallCallback(SalEvent::KeyInput, &aEvent);
+    if (eState == ButtonKeyState::Pressed)
+        bStopProcessingKey = rFrame.CallCallback(SalEvent::KeyInput, &aEvent);
     else
-        bStopProcessingKey = m_rFrame.CallCallback(SalEvent::KeyUp, &aEvent);
+        bStopProcessingKey = rFrame.CallCallback(SalEvent::KeyUp, &aEvent);
+    if (bStopProcessingKey)
+        pEvent->accept();
     return bStopProcessingKey;
 }
 
-bool Qt5Widget::event(QEvent* pEvent)
+bool Qt5Widget::handleEvent(Qt5Frame& rFrame, const QWidget& rWidget, QEvent* pEvent)
 {
     if (pEvent->type() == QEvent::ShortcutOverride)
     {
@@ -459,17 +467,22 @@ bool Qt5Widget::event(QEvent* pEvent)
         // and if it's handled - disable the shortcut, it should have been activated.
         // Don't process keyPressEvent generated after disabling shortcut since it was handled here.
         // If event is not handled, don't accept it and let Qt activate related shortcut.
-        if (handleKeyEvent(static_cast<QKeyEvent*>(pEvent), true))
-            pEvent->accept();
+        if (handleKeyEvent(rFrame, rWidget, static_cast<QKeyEvent*>(pEvent),
+                           ButtonKeyState::Pressed))
+            return true;
     }
+    return false;
+}
 
-    return QWidget::event(pEvent);
+bool Qt5Widget::event(QEvent* pEvent)
+{
+    return handleEvent(m_rFrame, *this, pEvent) || QWidget::event(pEvent);
 }
 
 void Qt5Widget::keyReleaseEvent(QKeyEvent* pEvent)
 {
-    if (handleKeyEvent(pEvent, false))
-        pEvent->accept();
+    if (!handleKeyReleaseEvent(m_rFrame, *this, pEvent))
+        QWidget::keyReleaseEvent(pEvent);
 }
 
 void Qt5Widget::focusInEvent(QFocusEvent*) { m_rFrame.CallCallback(SalEvent::GetFocus, nullptr); }
@@ -519,7 +532,7 @@ static ExtTextInputAttr lcl_MapUndrelineStyle(QTextCharFormat::UnderlineStyle us
 void Qt5Widget::inputMethodEvent(QInputMethodEvent* pEvent)
 {
     if (!pEvent->commitString().isEmpty())
-        commitText(pEvent->commitString());
+        commitText(m_rFrame, pEvent->commitString());
     else
     {
         SalExtTextInputEvent aInputEvent;