QmlDesigner: Allow starting free drag on initial selection press

Changed object selection to be done on press instead of click, and
the initial press now also starts free drag of the selected object
after a short distance moved to prevent accidental drags.

Change-Id: I61656661cd734d167ef9f8db42d986f0e97402a3
Fixes: QDS-2376
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>

share/qtcreator/qml/qmlpuppet/mockfiles/EditView3D.qml

@@ -543,16 +543,61 @@ Item {
             MouseArea {
                 anchors.fill: parent
                 acceptedButtons: Qt.LeftButton
-                onClicked: {
+                hoverEnabled: false
+
+                property MouseArea3D freeDraggerArea
+                property point pressPoint
+                property bool initialMoveBlock: false
+
+                onPressed: {
                     if (viewRoot.editView) {
                         var pickResult = viewRoot.editView.pick(mouse.x, mouse.y);
                         handleObjectClicked(_generalHelper.resolvePick(pickResult.objectHit),
                                             mouse.modifiers & Qt.ControlModifier);
-                        if (!pickResult.objectHit)
+
+                        if (pickResult.objectHit) {
+                            if (transformMode === EditView3D.TransformMode.Move)
+                                freeDraggerArea = moveGizmo.freeDraggerArea;
+                            else if (transformMode === EditView3D.TransformMode.Rotate)
+                                freeDraggerArea = rotateGizmo.freeDraggerArea;
+                            else if (transformMode === EditView3D.TransformMode.Scale)
+                                freeDraggerArea = scaleGizmo.freeDraggerArea;
+                            pressPoint.x = mouse.x;
+                            pressPoint.y = mouse.y;
+                            initialMoveBlock = true;
+                        } else {
                             mouse.accepted = false;
                         }
                     }
                 }
+                onPositionChanged: {
+                    if (freeDraggerArea) {
+                        if (initialMoveBlock && Math.abs(pressPoint.x - mouse.x) + Math.abs(pressPoint.y - mouse.y) > 10) {
+                            // Don't force press event at actual press, as that puts the gizmo
+                            // in free-dragging state, which is bad UX if drag is not actually done
+                            freeDraggerArea.forcePressEvent(pressPoint.x, pressPoint.y);
+                            freeDraggerArea.forceMoveEvent(mouse.x, mouse.y);
+                            initialMoveBlock = false;
+                        } else {
+                            freeDraggerArea.forceMoveEvent(mouse.x, mouse.y);
+                        }
+                    }
+                }
+
+                function handleRelease(mouse)
+                {
+                    if (freeDraggerArea) {
+                        if (initialMoveBlock)
+                            freeDraggerArea.forceReleaseEvent(pressPoint.x, pressPoint.y);
+                        else
+                            freeDraggerArea.forceReleaseEvent(mouse.x, mouse.y);
+                        freeDraggerArea = null;
+                    }
+                }
+
+                onReleased: handleRelease(mouse)
+                onCanceled: handleRelease(mouse)
+            }
 
             DropArea {
                 anchors.fill: parent

share/qtcreator/qml/qmlpuppet/mockfiles/MoveGizmo.qml

@@ -38,6 +38,7 @@ Node {
                                      || planeX.dragging || planeY.dragging || planeZ.dragging
                                      || centerBall.dragging
     property MouseArea3D dragHelper: null
+    property alias freeDraggerArea: centerBall.mouseArea
 
     position: dragHelper.pivotScenePosition(targetNode)
 

share/qtcreator/qml/qmlpuppet/mockfiles/PlanarDraggable.qml

@@ -37,6 +37,7 @@ Model {
     property bool dragging: mouseArea.dragging
     property bool active: false
     property MouseArea3D dragHelper: null
+    property alias mouseArea: mouseArea
 
     readonly property bool hovering: mouseArea.hovering
 

share/qtcreator/qml/qmlpuppet/mockfiles/RotateGizmo.qml

@@ -39,6 +39,7 @@ Node {
     property MouseArea3D dragHelper: null
     property real currentAngle
     property point currentMousePos
+    property alias freeDraggerArea: mouseAreaFree
 
     position: dragHelper.pivotScenePosition(targetNode)
 

share/qtcreator/qml/qmlpuppet/mockfiles/ScaleGizmo.qml

@@ -37,6 +37,7 @@ Node {
                                      || planeX.dragging || planeY.dragging || planeZ.dragging
                                      || centerMouseArea.dragging
     property MouseArea3D dragHelper: null
+    property alias freeDraggerArea: centerMouseArea
 
     position: dragHelper.pivotScenePosition(targetNode)
 

share/qtcreator/qml/qmlpuppet/qml2puppet/editor3d/mousearea3d.cpp

@@ -512,6 +512,32 @@ double MouseArea3D::getRelativeScale(QQuick3DNode *node) const
     return (scenePos1 - scenePos2).length() / 100.;
 }
 
+void MouseArea3D::forcePressEvent(double x, double y)
+{
+    m_forceCaptureNextPress = true;
+
+    Qt::MouseButtons buttons;
+    Qt::KeyboardModifiers mods;
+    QMouseEvent event(QEvent::MouseButtonPress, QPointF(x, y), Qt::LeftButton, buttons, mods);
+    eventFilter(m_view3D, &event);
+}
+
+void QmlDesigner::Internal::MouseArea3D::forceMoveEvent(double x, double y)
+{
+    Qt::MouseButtons buttons;
+    Qt::KeyboardModifiers mods;
+    QMouseEvent event(QEvent::MouseMove, QPointF(x, y), Qt::LeftButton, buttons, mods);
+    eventFilter(m_view3D, &event);
+}
+
+void QmlDesigner::Internal::MouseArea3D::forceReleaseEvent(double x, double y)
+{
+    Qt::MouseButtons buttons;
+    Qt::KeyboardModifiers mods;
+    QMouseEvent event(QEvent::MouseButtonRelease, QPointF(x, y), Qt::LeftButton, buttons, mods);
+    eventFilter(m_view3D, &event);
+}
+
 QVector3D MouseArea3D::getMousePosInPlane(const MouseArea3D *helper,
                                           const QPointF &mousePosInView) const
 {
@@ -535,7 +561,8 @@ QVector3D MouseArea3D::getMousePosInPlane(const MouseArea3D *helper,
 bool MouseArea3D::eventFilter(QObject *, QEvent *event)
 {
     if (!m_active || (m_grabsMouse && s_mouseGrab && s_mouseGrab != this
-            && (m_priority <= s_mouseGrab->m_priority || s_mouseGrab->m_dragging))) {
+            && (m_priority <= s_mouseGrab->m_priority || s_mouseGrab->m_dragging
+                || s_mouseGrab->m_forceCaptureNextPress))) {
         return false;
     }
 
@@ -596,7 +623,8 @@ bool MouseArea3D::eventFilter(QObject *, QEvent *event)
                 m_dragHelper->setScale(sceneScale());
             }
             m_mousePosInPlane = getMousePosInPlane(m_dragHelper, mouseEvent->pos());
-            if (mouseOnTopOfMouseArea(m_mousePosInPlane, mouseEvent->pos())) {
+            if (m_forceCaptureNextPress || mouseOnTopOfMouseArea(m_mousePosInPlane, mouseEvent->pos())) {
+                m_forceCaptureNextPress = false;
                 setDragging(true);
                 emit pressed(m_mousePosInPlane.toVector2D(), mouseEvent->pos(), pickAngle);
                 if (m_grabsMouse) {

share/qtcreator/qml/qmlpuppet/qml2puppet/editor3d/mousearea3d.h

@@ -116,6 +116,10 @@ public slots:
     Q_INVOKABLE QVector3D pivotScenePosition(QQuick3DNode *node) const;
     Q_INVOKABLE double getRelativeScale(QQuick3DNode *node) const;
 
+    Q_INVOKABLE void forcePressEvent(double x, double y);
+    Q_INVOKABLE void forceMoveEvent(double x, double y);
+    Q_INVOKABLE void forceReleaseEvent(double x, double y);
+
 signals:
     void view3DChanged();
 
@@ -171,6 +175,7 @@ private:
     qreal m_minAngle = 0.;
     QQuick3DNode *m_pickNode = nullptr;
     MouseArea3D *m_dragHelper = nullptr;
+    bool m_forceCaptureNextPress = false;
 };
 
 }