Implement undo redo commands

Author: paceholder

CMakeLists.txt

@@ -99,6 +99,7 @@ set(CPP_SOURCE_FILES
   src/NodeState.cpp
   src/NodeStyle.cpp
   src/StyleCollection.cpp
+  src/UndoCommands.cpp
   src/locateNode.cpp
 )
 

examples/graph/CustomGraphModel.cpp

@@ -203,6 +203,9 @@ nodeData(NodeId nodeId, NodeRole role) const
     }
     break;
 
+    case NodeRole::InternalData:
+      break;
+
     case NodeRole::NumberOfInPorts:
       result = 1u;
       break;
@@ -259,6 +262,9 @@ setNodeData(NodeId   nodeId,
     case NodeRole::Style:
       break;
 
+    case NodeRole::InternalData:
+      break;
+
     case NodeRole::NumberOfInPorts:
       break;
 
@@ -347,9 +353,8 @@ deleteConnection(ConnectionId const connectionId)
 
         PortType opposite = oppositePort(portType);
 
-        auto oppositePair =
-          std::make_pair(getNodeId(opposite, connectionId),
-                         getPortIndex(opposite, connectionId));
+        auto oppositePair = std::make_pair(getNodeId(opposite, connectionId),
+                                           getPortIndex(opposite, connectionId));
         it->second.erase(oppositePair);
 
         if (it->second.empty())
@@ -398,13 +403,14 @@ saveNode(NodeId const nodeId) const
 
   nodeJson["id"] = static_cast<qint64>(nodeId);
 
-  QPointF const pos =
-    nodeData(nodeId, NodeRole::Position).value<QPointF>();
+  {
+    QPointF const pos = nodeData(nodeId, NodeRole::Position).value<QPointF>();
 
-  QJsonObject posJson;
-  posJson["x"] = pos.x();
-  posJson["y"] = pos.y();
-  nodeJson["position"] = posJson;
+    QJsonObject posJson;
+    posJson["x"] = pos.x();
+    posJson["y"] = pos.y();
+    nodeJson["position"] = posJson;
+  }
 
   return nodeJson;
 }
@@ -414,19 +420,25 @@ void
 CustomGraphModel::
 loadNode(QJsonObject const & nodeJson)
 {
-  NodeId nodeId = static_cast<NodeId>(nodeJson["id"].toInt());
+  NodeId restoredNodeId = static_cast<NodeId>(nodeJson["id"].toInt());
 
-  _nextNodeId = std::max(_nextNodeId, nodeId);
+  // Next NodeId must be larger that any id existing in the graph
+  _nextNodeId = std::max(restoredNodeId + 1, _nextNodeId);
 
-  NodeId newId = addNode();
+  // Create new node.
+  _nodeIds.insert(restoredNodeId);
 
-  QJsonObject posJson = nodeJson["position"].toObject();
-  QPointF const pos(posJson["x"].toInt(),
-                    posJson["y"].toInt());
+  Q_EMIT nodeCreated(restoredNodeId);
 
-  setNodeData(newId,
-              NodeRole::Position,
-              pos);
+  {
+    QJsonObject posJson = nodeJson["position"].toObject();
+    QPointF const pos(posJson["x"].toDouble(),
+                      posJson["y"].toDouble());
+
+    setNodeData(restoredNodeId,
+                NodeRole::Position,
+                pos);
+  }
 }
 
 
@@ -449,10 +461,10 @@ void
 CustomGraphModel::
 loadConnection(QJsonObject const & connJson)
 {
-  ConnectionId connId{connJson["outNodeId"].toInt(),
-                      connJson["outPortIndex"].toInt(),
-                      connJson["intNodeId"].toInt(),
-                      connJson["inPortIndex"].toInt()};
+  ConnectionId connId{static_cast<NodeId>(connJson["outNodeId"].toInt()),
+                      static_cast<PortIndex>(connJson["outPortIndex"].toInt()),
+                      static_cast<NodeId>(connJson["intNodeId"].toInt()),
+                      static_cast<PortIndex>(connJson["inPortIndex"].toInt())};
 
   addConnection(connId);
 }

examples/graph/CustomGraphModel.hpp

@@ -25,21 +25,17 @@ class CustomGraphModel : public QtNodes::AbstractGraphModel
 {
   Q_OBJECT
 public:
-
   struct NodeGeometryData
   {
     QSize size;
     QPointF pos;
   };
 
-
 public:
-
   CustomGraphModel();
 
   ~CustomGraphModel() override;
 
-
   std::unordered_set<NodeId>
   allNodeIds() const override;
 
@@ -109,7 +105,6 @@ class CustomGraphModel : public QtNodes::AbstractGraphModel
   loadConnection(QJsonObject const & connJson) override;
 
 private:
-
   std::unordered_set<NodeId> _nodeIds;
 
   std::unordered_map<std::tuple<NodeId, PortType, PortIndex>,
@@ -122,5 +117,4 @@ class CustomGraphModel : public QtNodes::AbstractGraphModel
 
 
   unsigned int _nextNodeId;
-
 };

include/QtNodes/internal/AbstractGraphModel.hpp

@@ -7,6 +7,7 @@
 
 #include <QtCore/QObject>
 #include <QtCore/QVariant>
+#include <QtCore/QJsonObject>
 
 #include "Definitions.hpp"
 #include "ConnectionIdHash.hpp"
@@ -166,15 +167,33 @@ class NODE_EDITOR_PUBLIC AbstractGraphModel : public QObject
    */
   virtual
   QJsonObject
-  saveNode(NodeId const) const = 0;
+  saveNode(NodeId const) const { return {}; }
 
   /**
-   * Reimplement the function if you want to store/restore the node's
-   * inner state during undo/redo node deletion operations.
+   * Reimplement the function if you want to support:
+   *
+   *   - graph save/restore operations,
+   *   - undo/redo operations after deleting the node.
+   *
+   * QJsonObject must contain following fields:
+   * 
+   *
+   * ```
+   * {
+   *   id : 5,
+   *   position : { x : 100, y : 200 },
+   *   internal-data {
+   *     "your model specific data here"
+   *   }
+   * }
+   * ```
+   *
+   * The function must do almost exacly the same thing as the normal addNode().
+   * The main difference is in a model-specific `inner-data` processing.
    */
   virtual
   void
-  loadNode(QJsonObject const & nodeJson) = 0;
+  loadNode(QJsonObject const &) {}
 
   virtual
   QJsonObject

include/QtNodes/internal/BasicGraphicsScene.hpp

@@ -16,6 +16,9 @@
 
 #include "QUuidStdHash.hpp"
 
+
+class QUndoStack;
+
 namespace QtNodes
 {
 
@@ -47,6 +50,8 @@ class NODE_EDITOR_PUBLIC BasicGraphicsScene : public QGraphicsScene
   AbstractGraphModel &
   graphModel();
 
+  QUndoStack& undoStack();
+
 public:
 
   /// Creates a "draft" instance of ConnectionGraphicsObject.
@@ -207,6 +212,8 @@ private Q_SLOTS:
 
 
   std::unique_ptr<ConnectionGraphicsObject> _draftConnection;
+
+  QUndoStack* _undoStack;
 };
 
 

include/QtNodes/internal/DataFlowGraphModel.hpp

@@ -88,17 +88,17 @@ class NODE_EDITOR_PUBLIC DataFlowGraphModel : public AbstractGraphModel
   bool
   deleteNode(NodeId const nodeId) override;
 
+  QJsonObject
+  saveNode(NodeId const) const override;
+
   QJsonDocument
   save() const;
 
   void
-  load(QJsonDocument const &json);
-
-  QJsonObject
-  saveNode(NodeId const) const override;
+  loadNode(QJsonObject const & nodeJson) override;
 
   void
-  loadNode(QJsonObject const & nodeJson) override;
+  load(QJsonDocument const &json);
 
   QJsonObject
   saveConnection(ConnectionId const & connId) const override;
@@ -107,19 +107,19 @@ class NODE_EDITOR_PUBLIC DataFlowGraphModel : public AbstractGraphModel
   loadConnection(QJsonObject const & connJson) override;
 
 private:
-
   NodeId
   newNodeId() { return _nextNodeId++; }
 
   /**
    * The function could be used when we restore nodes from some file
-   * and the NodeId values are already known.
+   * and the NodeId values are already known.  In this case we must
+   * update internal counter for unique "next" node id in order not to
+   * repeat the values when incrementing.
    */
-  NodeId
-  newNodeId(NodeId const restoredNodeId)
+  void
+  setNextNodeId(NodeId const restoredNodeId)
   {
-    _nextNodeId = std::max(_nextNodeId, restoredNodeId);
-    return restoredNodeId;
+    _nextNodeId = std::max(_nextNodeId, restoredNodeId + 1);
   }
 
 private Q_SLOTS:

include/QtNodes/internal/DataFlowGraphicsScene.hpp

@@ -47,15 +47,6 @@ public Q_SLOTS:
                 PortIndex const portIndex);
 
 
-  //std::shared_ptr<Connection> restoreConnection(QJsonObject const & connectionJson);
-
-  //Node & restoreNode(QJsonObject const & nodeJson)
-
-
-  //void save() const;
-
-  //void load();
-
   QJsonDocument saveToJsonDocument() const;
 
   void loadFromJsonDocument(QJsonDocument const& json);

include/QtNodes/internal/Definitions.hpp

@@ -21,14 +21,15 @@ Q_NAMESPACE_EXPORT(NODE_EDITOR_PUBLIC)
 enum class NodeRole
 {
   Type             = 0, ///< Type of the current node, usually a string.
-  Position         = 1, ///< `QPointF` positon of the nod on the scene.
+  Position         = 1, ///< `QPointF` positon of the node on the scene.
   Size             = 2, ///< `QSize` for resizable nodes.
   CaptionVisible   = 3, ///< `bool` for caption visibility.
   Caption          = 4, ///< `QString` for node caption.
-  Style            = 5, ///< Custom NodeStyle.
-  NumberOfInPorts  = 6, ///< `unsigned int`
-  NumberOfOutPorts = 7, ///< `unsigned int`
-  Widget           = 8, ///< Optional `QWidget*` or `nullptr`
+  Style            = 5, ///< Custom NodeStyle as QJsonDocument
+  InternalData     = 6, ///< Node-stecific user data as QJsonObject
+  NumberOfInPorts  = 7, ///< `unsigned int`
+  NumberOfOutPorts = 9, ///< `unsigned int`
+  Widget           = 10, ///< Optional `QWidget*` or `nullptr`
 };
 Q_ENUM_NS(NodeRole)
 

src/BasicGraphicsScene.cpp

@@ -6,6 +6,8 @@
 #include <unordered_set>
 #include <utility>
 
+#include <QtGui/QUndoStack>
+
 #include <QtWidgets/QGraphicsSceneMoveEvent>
 #include <QtWidgets/QFileDialog>
 
@@ -18,8 +20,6 @@
 #include <QtCore/QJsonObject>
 #include <QtCore/QtGlobal>
 
-#include <QtCore/QDebug>
-
 #include "ConnectionGraphicsObject.hpp"
 #include "ConnectionIdUtils.hpp"
 #include "GraphicsView.hpp"
@@ -34,6 +34,7 @@ BasicGraphicsScene(AbstractGraphModel &graphModel,
                    QObject *   parent)
   : QGraphicsScene(parent)
   , _graphModel(graphModel)
+  , _undoStack(new QUndoStack(this))
 {
   setItemIndexMethod(QGraphicsScene::NoIndex);
 
@@ -88,6 +89,14 @@ graphModel()
 }
 
 
+QUndoStack &
+BasicGraphicsScene::
+undoStack()
+{
+  return *_undoStack;
+}
+
+
 std::unique_ptr<ConnectionGraphicsObject> const &
 BasicGraphicsScene::
 makeDraftConnection(ConnectionId const incompleteConnectionId)