From 1a47918bdb5f9ae75a538cd554a86a297b83fb5d Mon Sep 17 00:00:00 2001
From: Uwe Kindler <uwe.kindler@cetoni.de>
Date: Wed, 12 Sep 2018 15:37:07 +0200
Subject: [PATCH] Changed FloatingDockContainer to use an internal state
 machine to improve code clarity and to handle some corner cases on Windows
 where resizing and moving the floating window to the screen edges caused
 trouble

---
 src/FloatingDockContainer.cpp | 121 ++++++++++++++++++++--------------
 1 file changed, 70 insertions(+), 51 deletions(-)

diff --git a/src/FloatingDockContainer.cpp b/src/FloatingDockContainer.cpp
index b999b46..e381db7 100644
--- a/src/FloatingDockContainer.cpp
+++ b/src/FloatingDockContainer.cpp
@@ -66,8 +66,7 @@ struct FloatingDockContainerPrivate
 	CDockContainerWidget* DockContainer;
 	unsigned int zOrderIndex = ++zOrderCounter;
 	QPointer<CDockManager> DockManager;
-	bool DraggingActive = false;
-	bool NonClientAreaMouseButtonPress = false;
+	eDragState DraggingState = StateInactive;
 	QPoint DragStartMousePosition;
 	CDockContainerWidget* DropContainer = nullptr;
 	CDockAreaWidget* SingleDockArea = nullptr;
@@ -79,10 +78,24 @@ struct FloatingDockContainerPrivate
 
 	void titleMouseReleaseEvent();
 	void updateDropOverlays(const QPoint& GlobalPos);
-	void setDraggingActive(bool Active);
+
+	/**
+	 * Tests is a certain state is active
+	 */
+	bool isState(eDragState StateId) const
+	{
+		return StateId == DraggingState;
+	}
+
+	void setState(eDragState StateId)
+	{
+		DraggingState = StateId;
+	}
 };
 // struct FloatingDockContainerPrivate
 
+
+
 //============================================================================
 FloatingDockContainerPrivate::FloatingDockContainerPrivate(CFloatingDockContainer* _public) :
 	_this(_public)
@@ -95,7 +108,7 @@ FloatingDockContainerPrivate::FloatingDockContainerPrivate(CFloatingDockContaine
 //============================================================================
 void FloatingDockContainerPrivate::titleMouseReleaseEvent()
 {
-	setDraggingActive(false);
+	setState(StateInactive);
 	if (!DropContainer)
 	{
 		return;
@@ -202,18 +215,6 @@ void FloatingDockContainerPrivate::updateDropOverlays(const QPoint& GlobalPos)
 }
 
 
-//============================================================================
-void FloatingDockContainerPrivate::setDraggingActive(bool Active)
-{
-	qDebug() << "FloatingDockContainerPrivate::setDraggingActive " << Active;
-	DraggingActive = Active;
-	if (!DraggingActive)
-	{
-		NonClientAreaMouseButtonPress = false;
-	}
-}
-
-
 //============================================================================
 CFloatingDockContainer::CFloatingDockContainer(CDockManager* DockManager) :
 	QWidget(DockManager, Qt::Window),
@@ -289,18 +290,18 @@ void CFloatingDockContainer::changeEvent(QEvent *event)
 void CFloatingDockContainer::moveEvent(QMoveEvent *event)
 {
 	QWidget::moveEvent(event);
-	if (!qApp->mouseButtons().testFlag(Qt::LeftButton))
+	switch (d->DraggingState)
 	{
-		if (d->DraggingActive)
-		{
-			d->setDraggingActive(false);
-		}
-		return;
-	}
+	case StateMousePressed:
+		 d->setState(StateDraggingActive);
+		 d->updateDropOverlays(QCursor::pos());
+		 break;
 
-	if (d->DraggingActive)
-	{
-		d->updateDropOverlays(QCursor::pos());
+	case StateDraggingActive:
+		 d->updateDropOverlays(QCursor::pos());
+		 break;
+	default:
+		break;
 	}
 }
 
@@ -309,12 +310,16 @@ void CFloatingDockContainer::moveEvent(QMoveEvent *event)
 void CFloatingDockContainer::closeEvent(QCloseEvent *event)
 {
     qDebug() << "CFloatingDockContainer closeEvent";
-	d->setDraggingActive(false);
+	d->setState(StateInactive);
 
     if (isClosable())
-        QWidget::closeEvent(event);
+    {
+    	QWidget::closeEvent(event);
+    }
     else
+    {
         event->ignore();
+    }
 }
 
 
@@ -354,31 +359,45 @@ void CFloatingDockContainer::showEvent(QShowEvent *event)
 //============================================================================
 bool CFloatingDockContainer::event(QEvent *e)
 {
-	if (e->type() == QEvent::NonClientAreaMouseButtonPress)
+	switch (d->DraggingState)
 	{
-		if (QGuiApplication::mouseButtons() == Qt::LeftButton)
+	case StateInactive:
+		if (e->type() == QEvent::NonClientAreaMouseButtonPress && QGuiApplication::mouseButtons() == Qt::LeftButton)
 		{
 			qDebug() << "FloatingWidget::event Event::NonClientAreaMouseButtonPress" << e->type();
-			d->NonClientAreaMouseButtonPress = true;
+			d->setState(StateMousePressed);
 		}
-	}
-	else if (e->type() == QEvent::NonClientAreaMouseButtonDblClick)
-	{
-		qDebug() << "FloatingWidget::event QEvent::NonClientAreaMouseButtonDblClick";
-		d->setDraggingActive(false);
-	}
-	else if ((e->type() == QEvent::NonClientAreaMouseButtonRelease) && d->DraggingActive)
-	{
-		qDebug() << "FloatingWidget::event QEvent::NonClientAreaMouseButtonRelease";
-		d->titleMouseReleaseEvent();
-	}
-	else if (!d->DraggingActive && d->NonClientAreaMouseButtonPress && (e->type() == QEvent::Resize))
-	{
-		d->NonClientAreaMouseButtonPress = false;
-	}
-	else if (!d->DraggingActive && d->NonClientAreaMouseButtonPress && (e->type() == QEvent::Move))
-	{
-		d->setDraggingActive(true);
+	break;
+
+	case StateMousePressed:
+		switch (e->type())
+		{
+		case QEvent::NonClientAreaMouseButtonDblClick:
+			 qDebug() << "FloatingWidget::event QEvent::NonClientAreaMouseButtonDblClick";
+			 d->setState(StateInactive);
+			 break;
+
+		case QEvent::Resize:
+			 // If the first event after the mouse press is a resize event, then
+			 // the user resizes the window instead of dragging it around
+			 d->setState(StateInactive);
+			 break;
+
+		default:
+			break;
+		}
+	break;
+
+	case StateDraggingActive:
+		if (e->type() == QEvent::NonClientAreaMouseButtonRelease)
+		{
+			qDebug() << "FloatingWidget::event QEvent::NonClientAreaMouseButtonRelease";
+			d->titleMouseReleaseEvent();
+		}
+	break;
+
+	default:
+		break;
 	}
 
 	qDebug() << "CFloatingDockContainer::event " << e->type();
@@ -390,7 +409,7 @@ bool CFloatingDockContainer::event(QEvent *e)
 bool CFloatingDockContainer::eventFilter(QObject *watched, QEvent *event)
 {
 	Q_UNUSED(watched);
-	if (event->type() == QEvent::MouseButtonRelease && d->DraggingActive)
+	if (event->type() == QEvent::MouseButtonRelease && d->isState(StateDraggingActive))
 	{
 		qDebug() << "FloatingWidget::eventFilter QEvent::MouseButtonRelease";
 		d->titleMouseReleaseEvent();
@@ -404,7 +423,7 @@ bool CFloatingDockContainer::eventFilter(QObject *watched, QEvent *event)
 void CFloatingDockContainer::startFloating(const QPoint& Pos, const QSize& Size)
 {
 	resize(Size);
-	d->setDraggingActive(true);
+	d->setState(StateDraggingActive);
 	QPoint TargetPos = QCursor::pos() - Pos;
 	move(TargetPos);
     show();