     }
 
     private func rotateChevron(var angle: CGFloat) {
-        if angle < 0 {
-            angle = 0
+        if angle < CGFloat(-M_PI) {
+            angle = CGFloat(-M_PI)
         }
         else if angle > CGFloat(M_PI) {
             angle = CGFloat(M_PI)


    private func openChevron(isOpen: Bool = true) {
        if isOpen {
            rotateChevron(CGFloat(M_PI))
        }
        else {
            rotateChevron(0)
        }
    }


            openChevron()
            postNotification(streamCellDidOpenNotification, self)
        } else {
            var angle: CGFloat = -CGFloat(M_PI) + CGFloat(M_PI) * scrollView.contentOffset.x / revealWidth
            rotateChevron(angle)
            isOpen = false
        }
