Fix mis-calculation of spine cut positions on -n.

diff --git a/bookmaker.py b/bookmaker.py
index cfdf5c56ef8e3c78285dfaaae795a24071be6185..7b4583260a5aff23cf0431b32110a7fd02c50393 100755 (executable)
--- a/bookmaker.py
+++ b/bookmaker.py
@@ -256,7 +256,7 @@ class Nup4Geometry:
         self.shrink_for_margin = (A4_WIDTH - 2 * self.margin)/A4_WIDTH
         # NB: We define spine size un-shrunk, but .shrink_for_spine is used
         # with values shrunk for the margin, which we undo here.
-        spine_part_of_page = ((INNER_SPINE_MARGIN_PER_PAGE / A4_WIDTH/2)
+        spine_part_of_page = ((INNER_SPINE_MARGIN_PER_PAGE / (A4_WIDTH/2))
                               / self.shrink_for_margin)
         self.shrink_for_spine = 1 - spine_part_of_page