Fix flickering issue at certain rotation angles.
Fix flickering issue at certain rotation angles.

rdlester/openseadragon,msalsbery/openseadragon,jmnetus/openseadragon,openseadragon/openseadragon,avandecreme/openseadragon,msalsbery/openseadragon,jmnetus/openseadragon,seanich/openseadragon,rdlester/openseadragon,LarissaSmith/openseadragon,seanich/openseadragon,avandecreme/openseadragon,openseadragon/openseadragon,LarissaSmith/openseadragon