To observe targets in expanded depths of view in light field imaging, we design an open-source light field parallel refocusing code-free GUI tool named OpenRefocus, which is based on classical spatial projection integration. OpenRefocus has been successfully used for refocusing light field images selected from open-source datasets as well as captured using commercial light field cameras faster than other released light field refocusing programs. Considering its fast processing speed and user-friendly operations, OpenRefocus can be a useful tool for light field refocusing in many light field imaging applications.