Fixed start drag distance to be based on QApplication::startDragDistance, fixed dragging of dock widget title bar to support dragging in x and y direction

Author: Uwe Kindler

src/DockAreaTabBar.cpp

@@ -15,6 +15,7 @@
 #include <QDebug>
 #include <QBoxLayout>
 #include <QMenu>
+#include <QApplication>
 
 #include "FloatingDockContainer.h"
 #include "DockAreaWidget.h"
@@ -185,9 +186,10 @@ void CDockAreaTabBar::mouseMoveEvent(QMouseEvent* ev)
 		return;
 	}
 
-    int DragDistanceY = qAbs(d->DragStartMousePos.y() - ev->pos().y());
-    int MinDragDistanceY = this->height() / 2;
-	if (DragDistanceY >= MinDragDistanceY)
+    /*int DragDistanceY = qAbs(d->DragStartMousePos.y() - ev->pos().y());
+    int MinDragDistanceY = this->height() / 2;*/
+	int DragDistance = (d->DragStartMousePos - ev->pos()).manhattanLength();
+	if (DragDistance >= CDockManager::startDragDistance())
 	{
 		qDebug() << "CTabsScrollArea::startFloating";
 		startFloating(d->DragStartMousePos);

src/DockManager.cpp

@@ -44,6 +44,7 @@
 #include <QXmlStreamReader>
 #include <QSettings>
 #include <QMenu>
+#include <QApplication>
 
 #include "FloatingDockContainer.h"
 #include "DockOverlay.h"
@@ -629,6 +630,13 @@ bool CDockManager::isRestoringState() const
 	return d->RestoringState;
 }
 
+
+//===========================================================================
+int CDockManager::startDragDistance()
+{
+	return QApplication::startDragDistance() * 1.5;
+}
+
 } // namespace ads
 
 //---------------------------------------------------------------------------

src/DockManager.h

@@ -270,6 +270,12 @@ class ADS_EXPORT CDockManager : public CDockContainerWidget
 	 */
 	bool isRestoringState() const;
 
+	/**
+	 * The distance the user needs to move the mouse with the left button
+	 * hold down before a dock widget start floating
+	 */
+	static int startDragDistance();
+
 public slots:
 	/**
 	 * Opens the perspective with the given name.

src/DockWidgetTab.cpp

@@ -281,8 +281,7 @@ void CDockWidgetTab::mouseMoveEvent(QMouseEvent* ev)
 
     // Maybe a fixed drag distance is better here ?
     int DragDistanceY = qAbs(d->DragStartMousePosition.y() - ev->pos().y());
-    int MinDragDistanceY = d->DockArea->titleBarGeometry().height() / 2;
-    if (DragDistanceY >= MinDragDistanceY)
+    if (DragDistanceY >= CDockManager::startDragDistance())
 	{
 		// If this is the last dock area in a dock container with only
     	// one single dock widget it does not make  sense to move it to a new