#228 Draft a RandomLayout to initialze random node positions.

Signed-off-by: cneben <benoit@destrat.io>

samples/layouts/layouts.qml

@@ -79,10 +79,16 @@ ApplicationWindow {
                 graph.insertEdge(n12, n122)
                 //graph.insertEdge(n121, n1211)
                 graph.insertEdge(n13, n131)
+
+                randomLayout.layout(n1);
             }
             Qan.OrgTreeLayout {
                 id: orgTreeLayout
             }
+            Qan.RandomLayout {
+                id: randomLayout
+                layoutRect: Qt.rect(100, 100, 1000, 1000)
+            }
         } // Qan.Graph
         Menu {      // Context menu demonstration
             id: contextMenu
@@ -105,14 +111,19 @@ ApplicationWindow {
             anchors.top: parent.top
             anchors.topMargin: 10
             anchors.horizontalCenter: parent.horizontalCenter
-            width: 420
+            width: 470
             height: 50
             padding: 2
             RowLayout {
                 anchors.fill: parent
                 Label {
                     text: "Apply OrgTree:"
                 }
+                Button {
+                    text: 'Random'
+                    Material.roundedScale: Material.SmallScale
+                    onClicked: randomLayout.layout(graphView.treeRoot)
+                }
                 Button {
                     text: 'Mixed'
                     Material.roundedScale: Material.SmallScale

src/QuickQanava.h

@@ -118,6 +118,7 @@ struct QuickQanava {
         qmlRegisterType<qan::RightResizer>("QuickQanava", 2, 0, "RightResizer");
         qmlRegisterType<qan::BottomResizer>("QuickQanava", 2, 0, "BottomResizer");
 
+        qmlRegisterType<qan::RandomLayout>("QuickQanava", 2, 0, "RandomLayout");
         qmlRegisterType<qan::OrgTreeLayout>("QuickQanava", 2, 0, "OrgTreeLayout");
     } // initialize()
 };

src/qanGraph.h

@@ -1073,7 +1073,7 @@ class Graph : public gtpo::graph<QQuickItem, qan::Node, qan::Group, qan::Edge>
      */
     std::vector<const qan::Node*>   collectDfs(const qan::Node& node, bool collectGroup = false) const noexcept;
 
-    //! \copydoc collectDfs()
+    //! Collect all out nodes of \c nodes using DFS, return an unordered set of subnodes (nodes in node are _not_ in returned set).
     auto    collectSubNodes(const QVector<qan::Node*> nodes, bool collectGroup = false) const noexcept -> std::unordered_set<const qan::Node*>;
 
 private:

src/qanTreeLayouts.cpp

@@ -142,6 +142,58 @@ void    NaiveTreeLayout::layout(qan::Node* root) noexcept
 //-----------------------------------------------------------------------------
 
 
+/* OrgTreeLayout Object Management *///----------------------------------------
+RandomLayout::RandomLayout(QObject* parent) noexcept :
+    QObject{parent}
+{
+}
+RandomLayout::~RandomLayout() { }
+
+bool    RandomLayout::setLayoutRect(QRectF layoutRect) noexcept
+{
+    _layoutRect = layoutRect;
+    emit layoutRectChanged();
+    return true;
+}
+const QRectF    RandomLayout::getLayoutRect() const noexcept { return _layoutRect; }
+
+void    RandomLayout::layout(qan::Node& root) noexcept
+{
+    // In nodes, out nodes, adjacent nodes ?
+    const auto graph = root.getGraph();
+    if (graph == nullptr)
+        return;
+    if (root.getItem() == nullptr)
+        return;
+
+    // Generate a 1000x1000 layout rect centered on root if the user has not specified one
+    const auto rootPosition = root.getItem()->position();
+    const auto layoutRect = _layoutRect.isEmpty() ? QRectF{rootPosition.x() - 500, rootPosition.y() - 500, 1000., 1000.} :
+                                                    _layoutRect;
+
+    auto outNodes = graph->collectSubNodes(QVector<qan::Node*>{&root}, false);
+    outNodes.insert(&root);
+    for (auto n : outNodes) {
+        auto node = const_cast<qan::Node*>(n);
+        if (node->getItem() == nullptr)
+            continue;
+        const auto nodeBr = node->getItem()->boundingRect();
+        qreal maxX = layoutRect.width() - nodeBr.width();
+        qreal maxY = layoutRect.height() - nodeBr.height();
+        // Generate and set random x and y positions within available area
+        node->getItem()->setX(QRandomGenerator::global()->bounded(maxX) + layoutRect.left());
+        node->getItem()->setY(QRandomGenerator::global()->bounded(maxY) + layoutRect.top());
+    }
+}
+
+void    RandomLayout::layout(qan::Node* root) noexcept
+{
+    if (root != nullptr)
+        layout(*root);
+}
+//-----------------------------------------------------------------------------
+
+
 /* OrgTreeLayout Object Management *///----------------------------------------
 OrgTreeLayout::OrgTreeLayout(QObject* parent) noexcept :
     QObject{parent}

src/qanTreeLayouts.h

@@ -74,7 +74,57 @@ class NaiveTreeLayout : public QObject
 };
 
 
-/*! \brief
+/*! \brief Layout nodes randomly inside a bounding rect.
+ * \nosubgrouping
+ */
+class RandomLayout : public QObject
+{
+    Q_OBJECT
+    /*! \name RandomLayout Object Management *///-----------------------------
+    //@{
+public:
+    explicit RandomLayout(QObject* parent = nullptr) noexcept;
+    virtual ~RandomLayout() override;
+    RandomLayout(const RandomLayout&) = delete;
+    RandomLayout& operator=(const RandomLayout&) = delete;
+    RandomLayout(RandomLayout&&) = delete;
+    RandomLayout& operator=(RandomLayout&&) = delete;
+
+public:
+    //! \copydoc getLayoutRect()
+    Q_PROPERTY(QRectF layoutRect READ getLayoutRect WRITE setLayoutRect NOTIFY layoutRectChanged FINAL)
+    //! \copydoc getLayoutRect()
+    bool            setLayoutRect(QRectF layoutRect) noexcept;
+    //! \copydoc getLayoutRect()
+    const QRectF    getLayoutRect() const noexcept;
+protected:
+    //! \copydoc getLayoutRect()
+    QRectF          _layoutRect = QRectF{};
+signals:
+    //! \copydoc getLayoutRect()
+    void            layoutRectChanged();
+
+public:
+    /*! \brief Apply a random layout fitting nodes positions inside \c layoutRect.
+     * If \c layoutRect is empty, generate a 1000x1000 default rect around \c root position.
+     */
+    void                layout(qan::Node& root) noexcept;
+
+    //! QML invokable version of layout().
+    Q_INVOKABLE void    layout(qan::Node* root) noexcept;
+    //@}
+    //-------------------------------------------------------------------------
+};
+
+
+/*! \brief Org chart naive recursive variant of Reingold-Tilford algorithm with shifting.
+ *
+ * This algorithm layout tree in an "Org chart" fashion using no space optimization,
+ * respecting node ordering and working for n-ary trees.
+ *
+ * \note This layout does not enforces that the input graph is a tree, laying out
+ * a non-tree graph might lead to infinite recursion.
+ *
  * \nosubgrouping
  */
 class OrgTreeLayout : public QObject
@@ -107,7 +157,7 @@ class OrgTreeLayout : public QObject
     //! \copydoc LayoutOrientation
     Q_PROPERTY(LayoutOrientation layoutOrientation READ getLayoutOrientation WRITE setLayoutOrientation NOTIFY layoutOrientationChanged FINAL)
     //! \copydoc LayoutOrientation
-    virtual bool            setLayoutOrientation(LayoutOrientation layoutOrientation) noexcept;
+    bool                    setLayoutOrientation(LayoutOrientation layoutOrientation) noexcept;
     //! \copydoc LayoutOrientation
     LayoutOrientation       getLayoutOrientation() noexcept;
     //! \copydoc LayoutOrientation