From 7a4e9d2e834ae131d05981392985ce1257422a38 Mon Sep 17 00:00:00 2001
From: Craig Watson <craig@watsons.ch>
Date: Tue, 10 Nov 2015 13:20:03 +0100
Subject: [PATCH] Removed UBGraphicsPolygonItem::shape()

Long version:

UBGraphicsPolygonItem::shape() sometimes caused OpenBoard to crash due to
inifinite recursion. This is easily replicated by trying to use the
highlighting tool.

The reason is: shape() calls boundingRect(); this function's definition is:

     QRectF QGraphicsPolygonItem::boundingRect() const
     {
          Q_D(const QGraphicsPolygonItem);
          if (d->boundingRect.isNull()) {
              qreal pw = pen().style() == Qt::NoPen ? qreal(0) : pen().widthF();
              if (pw == 0.0)
                  d->boundingRect = d->polygon.boundingRect();
              else
                  d->boundingRect = shape().controlPointRect();
          }
          return d->boundingRect;
      }

In the case where pw != 0, the shape() function is called. However, it
is shape() from the derived class, not the base class, which is called.
In other words, UBGraphicsPolygonItem::shape() is called rather than
QGraphicsPolygonItem::shape().

This means that boundingRect() is called again from within shape(), and
so on, causing the program to crash.

The fix was simply to remove UBGraphicsPolygonItem::shape(), as it
appears to provide the same (or very similar) functionality to that of
the base class's shape() function.

In case this shape() function actually is needed, another workaround
should be implemented to prevent this infinite recursion.
---
 src/domain/UBGraphicsPolygonItem.cpp | 10 ----------
 src/domain/UBGraphicsPolygonItem.h   |  1 -
 2 files changed, 11 deletions(-)

diff --git a/src/domain/UBGraphicsPolygonItem.cpp b/src/domain/UBGraphicsPolygonItem.cpp
index bfbd515e..1f5b40c3 100644
--- a/src/domain/UBGraphicsPolygonItem.cpp
+++ b/src/domain/UBGraphicsPolygonItem.cpp
@@ -211,16 +211,6 @@ void UBGraphicsPolygonItem::paint ( QPainter * painter, const QStyleOptionGraphi
     QGraphicsPolygonItem::paint(painter, option, widget);
 }
 
-QPainterPath UBGraphicsPolygonItem::shape() const
-{
-
-    QPainterPath path;
-    path.addRect(boundingRect());
-
-    return path;
-}
-
-
 UBGraphicsScene* UBGraphicsPolygonItem::scene()
 {
     return qobject_cast<UBGraphicsScene*>(QGraphicsPolygonItem::scene());
diff --git a/src/domain/UBGraphicsPolygonItem.h b/src/domain/UBGraphicsPolygonItem.h
index 1296b65d..600e4598 100644
--- a/src/domain/UBGraphicsPolygonItem.h
+++ b/src/domain/UBGraphicsPolygonItem.h
@@ -132,7 +132,6 @@ class UBGraphicsPolygonItem : public QGraphicsPolygonItem, public UBItem
 
     protected:
         void paint ( QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * widget);
-        QPainterPath shape () const;
 
 
     private: