I've read a few other issues about trying to prevent labels from rendering if they run off the edge of the map canvas. This is particularly a problem in Composer, where I get lots of country labels which are only half on the page.
https://issues.qgis.org/issues/10314
In the above post in the QGIS issue queue, Nyall Dawson says "There's an option in the global label settings to prevent clipped labels at the edge of maps".
I can't find this setting. Does anyone know where it is? Or any other solution for this problem?