diff --git a/src/calibre/gui2/library/alternate_views.py b/src/calibre/gui2/library/alternate_views.py
index 082911c200..301f5f482a 100644
--- a/src/calibre/gui2/library/alternate_views.py
+++ b/src/calibre/gui2/library/alternate_views.py
@@ -441,7 +441,7 @@ class CoverDelegate(QStyledItemDelegate):
             sz = f.pixelSize()
             if sz < 5:
                 sz = f.pointSize() * self.parent().logicalDpiY() / 72.0
-            self.title_height = max(25, sz + 10)
+            self.title_height = int(max(25, sz + 10))
         self.item_size = self.cover_size + QSize(2 * self.MARGIN, (2 * self.MARGIN) + self.title_height)
         if self.emblem_size > 0:
             extra = self.emblem_size + self.MARGIN