#228 Draft queue based BFS. Strat naive layout implementation. WIP.

Signed-off-by: cneben <[email protected]>
cneben · Aug 13, 2024 · 1593eb3 · 1593eb3
1 parent 1549900
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Showing 4 changed files with 73 additions and 8 deletions.
diff --git a/samples/layouts/layouts.cpp b/samples/layouts/layouts.cpp
@@ -39,13 +39,15 @@
 
 // QuickQanava headers
 #include <QuickQanava.h>
+#include "./qanOrgTreeLayout.h"
 
 //-----------------------------------------------------------------------------
 int	main( int argc, char** argv )
 {
     QGuiApplication app(argc, argv);
     QQuickStyle::setStyle("Material");
     QQmlApplicationEngine* engine = new QQmlApplicationEngine();
+    qmlRegisterType<qan::OrgTreeLayout>("QuickQanava", 2, 0, "OrgTreeLayout");
     engine->addPluginPath(QStringLiteral("../../src")); // Necessary only for development when plugin is not installed to QTDIR/qml
     QuickQanava::initialize(engine);
     engine->load(QUrl("qrc:/layouts.qml"));

diff --git a/samples/layouts/layouts.qml b/samples/layouts/layouts.qml
@@ -47,16 +47,29 @@ ApplicationWindow {
             parent: graphView
             id: graph
             Component.onCompleted: {
-                var n1 = graph.insertNode()
-                n1.label = "Hello World"; n1.item.x=15; n1.item.y= 25
+                let n1 = graph.insertNode()
+                n1.label = "n1"; n1.item.x=15; n1.item.y= 25
                 n1.item.ratio = 0.4
-                var n2 = graph.insertNode()
-                n2.label = "Node 2"; n2.item.x=15; n2.item.y= 125
 
-                var e = graph.insertEdge(n1, n2);
+                let n11 = graph.insertNode()
+                n11.label = "n11"; n11.item.x=15; n11.item.y= 125
+                let n12 = graph.insertNode()
+                n12.label = "n12"; n12.item.x=125; n12.item.y= 125
+
+
+                let n121 = graph.insertNode()
+                n121.label = "n121"; n121.item.x=125; n121.item.y= 225
+
+                graph.insertEdge(n1, n12);
+                graph.insertEdge(n1, n11);
+                graph.insertEdge(n12, n121);
+
+                orgTreeLayout.layout(n1);
+            }
+            Qan.OrgTreeLayout {
+                id: orgTreeLayout
             }
         } // Qan.Graph
-
         Menu {      // Context menu demonstration
             id: contextMenu
             MenuItem {

diff --git a/samples/layouts/qanOrgTreeLayout.cpp b/samples/layouts/qanOrgTreeLayout.cpp
@@ -33,7 +33,8 @@
 //-----------------------------------------------------------------------------
 
 // Std headers
-#include <memory>
+#include <queue>
+#include <unordered_set>
 
 // Qt headers
 #include <QQmlProperty>
@@ -65,8 +66,54 @@ void    OrgTreeLayout::layout(qan::Node& root) noexcept
     // 2. Layout the tree bottom up
     // 3. Shift the tree to align root to it's original position.
 
+    const auto collectBFS = [](qan::Node* root) -> std::vector<std::vector<qan::Node*>> {
+        std::vector<std::vector<qan::Node*>> r;
+        if (root == nullptr)
+            return r;
+
+        // <-- hand tuned ChatGPT code
+        std::queue<std::pair<Node*, int>> nodeLevelqueue;
+        std::unordered_set<Node*> visited;
+
+        nodeLevelqueue.push({root, 0});
+        visited.insert(root);
+
+        while (!nodeLevelqueue.empty()) {
+            auto [current, level] = nodeLevelqueue.front();
+            nodeLevelqueue.pop();
+
+            if (r.size() <= level)
+                r.resize(level + 1);    // Resize() initialize new items
+            r[level].push_back(current);
+            for (auto child : current->get_out_nodes()) {             // Enqueue unvisited children with their level
+                if (visited.find(child) == visited.end()) {
+                    nodeLevelqueue.push({child, level + 1});
+                    visited.insert(child);
+                }
+            }
+        }
+        // <-- ChatGPT code
+        return r;
+    };
+
     // 1. BFS
+    const auto levels = collectBFS(&root);
+
+    // Debug
+    int l = 0;
+    for (const auto& level: levels) {
+        std::cerr << l++ << ": ";
+        for (const auto node: level)
+            std::cerr << node->getLabel().toStdString() << "\t";
+        std::cerr << std::endl;
+    }
+}
 
+void    OrgTreeLayout::layout(qan::Node* root) noexcept
+{
+    qWarning() << "qan::OrgTreeLayout::layout(): root=" << root;
+    if (root != nullptr)
+        layout(*root);
 }
 //-----------------------------------------------------------------------------
 

diff --git a/samples/layouts/qanOrgTreeLayout.h b/samples/layouts/qanOrgTreeLayout.h
@@ -75,7 +75,10 @@ class OrgTreeLayout : public QObject
      * running this algorithm on a non tree subgraph might lead to inifinite recursions or
      * invalid layouts.
      */
-    Q_INVOKABLE virtual void    layout(qan::Node& root) noexcept;
+    void                layout(qan::Node& root) noexcept;
+
+    //! QML invokable version of layout().
+    Q_INVOKABLE void    layout(qan::Node* root) noexcept;
     //@}
     //-------------------------------------------------------------------------
 };