Mine

Index: uielement.h
===================================================================
--- uielement.h	(revision 94509)
+++ uielement.h	(working copy)
@@ -68,7 +68,8 @@
 		SHAPE_EMPTY      = 0x20,	// there's is nothing to draw, the cached path may be NULL
 		SHAPE_NORMAL     = 0x40,	// normal drawing
 		SHAPE_DEGENERATE = 0x80,	// degenerate drawing, use the Stroke brush for filling
-		SHAPE_MASK       = (SHAPE_EMPTY | SHAPE_NORMAL | SHAPE_DEGENERATE)
+		SHAPE_RADII      = 0x100,
+		SHAPE_MASK       = (SHAPE_EMPTY | SHAPE_NORMAL | SHAPE_DEGENERATE | SHAPE_RADII)
 	};
 	
 	int flags;
Index: shape.cpp
===================================================================
--- shape.cpp	(revision 94509)
+++ shape.cpp	(working copy)
@@ -499,6 +499,12 @@
 	}
 }
 
+Rect
+Shape::ComputeLargestRectangle ()
+{
+	return Rect ();
+}
+
 Brush *
 shape_get_fill (Shape *shape)
 {
@@ -763,6 +769,15 @@
 	// note: both moon_rounded_rectangle and moon_ellipse close the path
 }
 
+Rect
+Ellipse::ComputeLargestRectangle ()
+{
+	double t = GetValue (Shape::StrokeThicknessProperty)->AsDouble ();
+	double x = (GetValue (FrameworkElement::WidthProperty)->AsDouble () - t) * cos (M_PI_2);
+	double y = (GetValue (FrameworkElement::HeightProperty)->AsDouble () - t) * sin (M_PI_2);
+	return bounds.GrowBy (-x, -y).RoundIn ();
+}
+
 void
 Ellipse::OnPropertyChanged (DependencyProperty *prop)
 {
@@ -809,8 +824,8 @@
 	if (!SetupLine (cr))
 		return drawn;
 
-	// FIXME: is it worth checking for round-corners ?
-	SetupLineJoinMiter (cr);
+	if (!HasRadii ())
+		SetupLineJoinMiter (cr);
 
 	// Draw if the path wasn't drawn by the Fill call
 	if (!drawn)
@@ -899,7 +914,7 @@
 				radius_x = radius_y = t / 2;
 			break;
 		}
-		SetShapeFlags (UIElement::SHAPE_DEGENERATE);
+		SetShapeFlags (round ? (UIElementFlags)(UIElement::SHAPE_DEGENERATE | UIElement::SHAPE_RADII) : UIElement::SHAPE_DEGENERATE);
 		goto shape;
 	} else {
 		// (b) the thickness is larger (or equal) to half the width or half the height
@@ -916,7 +931,7 @@
 					radius_y = h;
 				}
 			}
-			SetShapeFlags (UIElement::SHAPE_DEGENERATE);
+			SetShapeFlags (round ? (UIElementFlags)(UIElement::SHAPE_DEGENERATE | UIElement::SHAPE_RADII) : UIElement::SHAPE_DEGENERATE);
 			goto shape;
 		}
 	}
@@ -954,7 +969,7 @@
 	if (compute_origin && (!IsStroked () || (t != 1.0)))
 		x = y = t / 2.0;
 
-	SetShapeFlags (UIElement::SHAPE_NORMAL);
+	SetShapeFlags (round ? (UIElementFlags)(UIElement::SHAPE_NORMAL | UIElement::SHAPE_RADII) : UIElement::SHAPE_NORMAL);
 
 shape:
 	// rounded-corner rectangle ?
@@ -1004,10 +1019,22 @@
 	return ((*rx != 0.0) && (*ry != 0.0));
 }
 
+Rect
+Rectangle::ComputeLargestRectangle ()
+{
+	double x = GetValue (Shape::StrokeThicknessProperty)->AsDouble ();
+	double y = x;
+	if (HasRadii ()) {
+		x += GetValue (Rectangle::RadiusXProperty)->AsDouble ();
+		y += GetValue (Rectangle::RadiusYProperty)->AsDouble ();
+	}
+	return bounds.GrowBy (-x, -y).RoundIn ();
+}
+
 double
 rectangle_get_radius_x (Rectangle *rectangle)
 {
-	return rectangle->GetValue (Rectangle::RadiusXProperty)->AsDouble();
+	return rectangle->GetValue (Rectangle::RadiusXProperty)->AsDouble ();
 }
 
 void
Index: shape.h
===================================================================
--- shape.h	(revision 94509)
+++ shape.h	(working copy)
@@ -71,6 +71,7 @@
 	virtual void Render (cairo_t *cr, int x, int y, int width, int height);
 	virtual void GetSizeForBrush (cairo_t *cr, double *width, double *height);
 	virtual void ComputeBounds ();
+	virtual Rect ComputeLargestRectangle ();
 	virtual bool InsideObject (cairo_t *cr, double x, double y);
 	virtual Point GetTransformOrigin ();
 	
@@ -103,6 +104,7 @@
 	bool IsEmpty () { return (flags & UIElement::SHAPE_EMPTY); };
 	bool IsNormal () { return (flags & UIElement::SHAPE_NORMAL); };
 	bool IsDegenerate () { return (flags & UIElement::SHAPE_DEGENERATE); };
+	bool HasRadii () { return (flags & UIElement::SHAPE_RADII); };
 	void SetShapeFlags (UIElementFlags sf) { flags &= ~UIElement::SHAPE_MASK; flags |= sf; };
 };
 
@@ -141,6 +143,7 @@
 	virtual Type::Kind GetObjectType () { return Type::ELLIPSE; };
 
 	virtual void BuildPath ();
+	virtual Rect ComputeLargestRectangle ();
 	virtual bool CanFill () { return true; }
 
 	virtual void OnPropertyChanged (DependencyProperty *prop);
@@ -163,6 +166,7 @@
 	virtual Type::Kind GetObjectType () { return Type::RECTANGLE; };
 
 	virtual void BuildPath ();
+	virtual Rect ComputeLargestRectangle ();
 
 	virtual void OnPropertyChanged (DependencyProperty *prop);