Avoid out-of-bounds access
Avoid out-of-bounds access

Task-number: QTBUG-33364
Change-Id: I33d713df5d60a349c48f109a5f76db5fa57573af
Reviewed-by: Laszlo Agocs <00c05606d635b5d8e1450a8536e4e2809abe4e80@digia.com>

kobolabs/qtgraphicaleffects