Runtime validation and error reporting

examples/calculator/DivisionModel.hpp

@@ -13,6 +13,9 @@
 /// In this example it has no logic.
 class DivisionModel : public MathOperationDataModel
 {
+private:
+  bool isModelValid = true;
+  QString modelValidationError = QString("");
 public:
 
   virtual
@@ -45,7 +48,7 @@ class DivisionModel : public MathOperationDataModel
       default:
         break;
     }
-	return QString("");
+    return QString("");
   }
 
   QString
@@ -56,6 +59,14 @@ class DivisionModel : public MathOperationDataModel
   clone() const override
   { return std::make_unique<DivisionModel>(); }
 
+  bool
+  isValid() const override 
+  { return isModelValid; }
+
+  QString
+  errorMessage() const override
+  { return modelValidationError; }
+
 public:
 
   void
@@ -74,14 +85,24 @@ class DivisionModel : public MathOperationDataModel
     auto n1 = _number1.lock();
     auto n2 = _number2.lock();
 
-    if (n1 && n2 && (n2->number() != 0.0))
+    if (n2 && (n2->number() == 0.0))
     {
-      _result = std::make_shared<NumberData>(n1->number() /
-                                             n2->number());
+      isModelValid = false;
+      modelValidationError = QString("Division by zero error");
     }
     else
     {
-      _result.reset();
+      isModelValid = true;
+      modelValidationError = QString("");
+      if (n1 && n2)
+      {
+        _result = std::make_shared<NumberData>(n1->number() /
+          n2->number());
+      }
+      else
+      {
+        _result.reset();
+      }
     }
 
     emit dataUpdated(outPortIndex);

src/FlowScene.cpp

@@ -215,6 +215,17 @@ setRegistry(std::shared_ptr<DataModelRegistry> registry)
 }
 
 
+void
+FlowScene::
+iterateOverNodes(std::function<void(Node*)> visitor)
+{
+  for (const auto& _node : _nodes)
+  {
+	visitor(_node.second.get());
+  }
+}
+
+
 //------------------------------------------------------------------------------
 
 void

src/FlowScene.hpp

@@ -6,6 +6,7 @@
 #include <unordered_map>
 #include <tuple>
 #include <memory>
+#include <functional>
 
 #include "Connection.hpp"
 #include "Export.hpp"
@@ -64,6 +65,9 @@ class NODE_EDITOR_PUBLIC FlowScene
   void
   setRegistry(std::shared_ptr<DataModelRegistry> registry);
 
+  void
+  iterateOverNodes(std::function<void(Node*)> visitor);
+
 public:
 
   void

src/Node.cpp

@@ -176,7 +176,12 @@ propagateData(std::shared_ptr<NodeData> nodeData,
               PortIndex inPortIndex) const
 {
   _nodeDataModel->setInData(nodeData, inPortIndex);
-
+
+  //Recalculate the nodes visuals. A data change can result in the node taking more space than before, so this forces a recalculate+repaint on the affected node
+  _nodeGraphicsObject->setGeometryChanged();
+  _nodeGeometry.recalculateSize();
+  _nodeGraphicsObject->update();
+  _nodeGraphicsObject->moveConnections();
 }
 
 

src/NodeDataModel.hpp

@@ -74,6 +74,14 @@ class NODE_EDITOR_PUBLIC NodeDataModel
   virtual
   bool
   resizable() const { return false; }
+
+  virtual
+  bool
+  isValid() const { return true; }
+
+  virtual
+  QString
+  errorMessage() const { return QString(""); }
 
 signals:
 

src/NodeGeometry.cpp

@@ -89,6 +89,12 @@ recalculateSize() const
   }
 
   _width = std::max(_width, captionWidth());
+
+  if (!_dataModel->isValid())
+  {
+    _width = std::max(_width, errorWidth());
+    _height += errorHeight() + _spacing;
+  }
 }
 
 
@@ -248,6 +254,26 @@ captionWidth() const
 }
 
 
+unsigned int
+NodeGeometry::
+errorHeight() const
+{
+  QString msg = _dataModel->errorMessage();
+
+  return _boldFontMetrics.boundingRect(msg).height();
+}
+
+
+unsigned int
+NodeGeometry::
+errorWidth() const
+{
+  QString msg = _dataModel->errorMessage();
+
+  return _boldFontMetrics.boundingRect(msg).width();
+}
+
+
 unsigned int
 NodeGeometry::
 portWidth(PortType portType) const
@@ -259,9 +285,13 @@ portWidth(PortType portType) const
     QString name;
 
     if (_dataModel->portCaptionVisible(portType, i))
+    {
       name = _dataModel->portCaption(portType, i);
+    }
     else
+    {
       name = _dataModel->dataType(portType, i).name;
+    }
 
     width = std::max(unsigned(_fontMetrics.width(name)),
                      width);

src/NodeGeometry.hpp

@@ -102,6 +102,12 @@ class NodeGeometry
   QPointF
   widgetPosition() const;
 
+  unsigned int
+  errorHeight() const;
+
+  unsigned int
+  errorWidth() const;
+
 private:
 
   unsigned int

src/NodePainter.cpp

@@ -40,6 +40,8 @@ paint(QPainter* painter,
   drawEntryLabels(painter, geom, state, model);
 
   drawResizeRect(painter, geom, model);
+
+  drawErrorRect(painter, geom, model);
 }
 
 
@@ -274,9 +276,13 @@ drawEntryLabels(QPainter * painter,
       QString s;
 
       if (model->portCaptionVisible(portType, i))
+      {
         s = model->portCaption(portType, i);
+      }
       else
+      {
         s = model->dataType(portType, i).name;
+      }
 
       auto rect = metrics.boundingRect(s);
 
@@ -319,3 +325,43 @@ drawResizeRect(QPainter * painter,
     painter->drawEllipse(geom.resizeRect());
   }
 }
+
+void
+NodePainter::
+drawErrorRect(QPainter * painter,
+               NodeGeometry const & geom,
+               NodeDataModel* const model)
+{
+  if (!model->isValid())
+  {
+    //Drawing the red background
+    painter->setBrush(Qt::red);
+
+    double const radius = 3.0;
+
+    NodeStyle const& nodeStyle = StyleCollection::nodeStyle();
+
+    float diam = nodeStyle.ConnectionPointDiameter;
+
+    QRectF    boundary(0.0, geom.height() - geom.errorHeight(), geom.width(), geom.errorHeight());
+    QMarginsF m(diam, diam, diam, diam);
+
+    painter->drawRoundedRect(boundary.marginsAdded(m), radius, radius);
+
+    //Drawing the error message itself
+    QString const &errorMsg = model->errorMessage();
+
+    QFont f = painter->font();
+
+    QFontMetrics metrics(f);
+
+    auto rect = metrics.boundingRect(errorMsg);
+
+    QPointF position((geom.width() - rect.width()) / 2.0,
+      geom.height() - (geom.errorHeight() - diam) / 2.0);
+
+    painter->setFont(f);
+    painter->setPen(nodeStyle.FontColor);
+    painter->drawText(position, errorMsg);
+  }
+}

src/NodePainter.hpp

@@ -62,4 +62,10 @@ class NodePainter
   drawResizeRect(QPainter* painter,
                  NodeGeometry const& geom,
                  NodeDataModel* const model);
+
+  static
+  void
+  drawErrorRect(QPainter * painter,
+                NodeGeometry const & geom,
+                NodeDataModel* const model);
 };