Core: Gui: DAGView: see following note:

Rework highlight rendering.
    Exception for topo sort.

src/Gui/DAGView/DAGModel.cpp

@@ -50,6 +50,7 @@
 #include <unordered_set>
 
 #include <Base/TimeInfo.h>
+#include <Base/Console.h>
 #include <Gui/Application.h>
 #include <Gui/Document.h>
 #include <Gui/ViewProviderDocumentObject.h>
@@ -240,14 +241,6 @@ void Model::slotNewObject(const ViewProviderDocumentObject &VPDObjectIn)
   
   //setup rectangle.
   auto *rectangle = (*theGraph)[virginVertex].rectangle.get();
-  rectangle->setPen(Qt::NoPen);
-  QColor preSelectionColor = qApp->palette().highlight().color();
-  preSelectionColor.setAlphaF(0.25);
-  rectangle->setPreselectionBrush(QBrush(preSelectionColor));
-  rectangle->setSelectionBrush(qApp->palette().highlight());
-  QColor bothSelectionColor = qApp->palette().highlight().color();
-  bothSelectionColor.setAlphaF(0.75);
-  rectangle->setBothBrush(QBrush(bothSelectionColor));
   rectangle->setEditingBrush(QBrush(Qt::yellow));
   
   (*theGraph)[virginVertex].icon->setPixmap(VPDObjectIn.getIcon().pixmap(iconSize, iconSize));
@@ -526,18 +519,17 @@ void Model::updateSlot()
       this->removeItem((*theGraph)[currentEdge].connector.get());
   }
   
-  
   indexVerticesEdges();
   Path sorted;
-  try {
-      // this sort gives the execute
-      boost::topological_sort(*theGraph, std::back_inserter(sorted));
+  try
+  {
+    boost::topological_sort(*theGraph, std::back_inserter(sorted));
   }
-  catch (const std::exception& e) {
-      std::cerr << "Document::recompute: " << e.what() << std::endl;
-      return;
+  catch(const boost::not_a_dag &)
+  {
+    Base::Console().Error("not a dag exception in DAGView::Model::updateSlot()\n");
+    return;
   }
-
   //index the vertices in sort order.
   int tempIndex = 0;
   for (const auto &currentVertex : sorted)

src/Gui/DAGView/DAGRectItem.cpp

@@ -23,8 +23,11 @@
 #include "PreCompiled.h"
 #ifndef _PreComp_
 #include <QPainter>
+#include <QApplication>
 #endif
 
+#include <QStyleOptionViewItem>
+
 #include "DAGRectItem.h"
 
 using namespace Gui;
@@ -39,25 +42,37 @@ RectItem::RectItem(QGraphicsItem* parent) : QGraphicsRectItem(parent)
 
 void RectItem::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 {
-  //TODO figure out how to mimic painting of itemviews. QStyle, QStyledItemDelegate.
+  painter->save();
   
-  QBrush brush = backgroundBrush;
-  if (selected)
-    brush = selectionBrush;
-  if (preSelected)
-    brush = preSelectionBrush;
-  if (selected && preSelected)
-    brush = bothBrush;
+  QStyleOptionViewItemV4 styleOption;
+  
+  styleOption.backgroundBrush = backgroundBrush;
   if (editing)
-    brush = editBrush;
+    styleOption.backgroundBrush = editBrush;
+  else
+  {
+    styleOption.state |= QStyle::State_Enabled;
+    if (selected)
+      styleOption.state |= QStyle::State_Selected;
+    if (preSelected)
+    {
+      if (!selected)
+      {
+        styleOption.state |= QStyle::State_Selected;
+        QPalette palette = styleOption.palette;
+        QColor tempColor = palette.color(QPalette::Active, QPalette::Highlight);
+        tempColor.setAlphaF(0.15);
+        palette.setColor(QPalette::Inactive, QPalette::Highlight, tempColor);
+        styleOption.palette = palette;
+      }
+      styleOption.state |= QStyle::State_MouseOver;
+    }
+  }
+  styleOption.rect = this->rect().toRect();
   
-  //heights are negative.
-  float radius = std::min(this->rect().width(), std::fabs(this->rect().height())) * 0.1;
-  painter->setBrush(brush);
-  painter->setPen(this->pen()); //should be Qt::NoPen.
-  painter->drawRoundedRect(this->rect(), radius, radius);
+  QApplication::style()->drawControl(QStyle::CE_ItemViewItem, &styleOption, painter);
   
-//   QGraphicsRectItem::paint(painter, option, widget);
+  painter->restore();
 }
 
 #include <moc_DAGRectItem.cpp>

src/Gui/DAGView/DAGRectItem.h

@@ -38,9 +38,6 @@ namespace Gui
     public:
       RectItem(QGraphicsItem* parent = 0);
       void setBackgroundBrush(const QBrush &brushIn){backgroundBrush = brushIn;}
-      void setPreselectionBrush(const QBrush &brushIn){preSelectionBrush = brushIn;}
-      void setSelectionBrush(const QBrush &brushIn){selectionBrush = brushIn;}
-      void setBothBrush(const QBrush &brushIn){bothBrush = brushIn;}
       void setEditingBrush(const QBrush &brushIn){editBrush = brushIn;}
       void preHighlightOn(){preSelected = true;}
       void preHighlightOff(){preSelected = false;}
@@ -55,9 +52,6 @@ namespace Gui
       virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
     private:
       QBrush backgroundBrush; //!< brush used for background. not used yet.
-      QBrush selectionBrush; //!< brush used when selected.
-      QBrush preSelectionBrush; //!< brush used when pre selected.
-      QBrush bothBrush; //!< brush for when both selected and preSelected.
       QBrush editBrush; //!< brush used when object is in edit mode.
       //start with booleans, may expand to state.
       bool selected;