diff --git a/gerber/render/cairo_backend.py b/gerber/render/cairo_backend.py
index 7acf29a..c3e9ac2 100644
--- a/gerber/render/cairo_backend.py
+++ b/gerber/render/cairo_backend.py
@@ -17,7 +17,7 @@
 
 
 import cairocffi as cairo
-from operator import mul, div
+from operator import mul
 import math
 import tempfile
 
@@ -45,7 +45,7 @@ class GerberCairoContext(GerberContext):
     def set_bounds(self, bounds, new_surface=False):
         origin_in_inch = (bounds[0][0], bounds[1][0])
         size_in_inch = (abs(bounds[0][1] - bounds[0][0]), abs(bounds[1][1] - bounds[1][0]))
-        size_in_pixels = map(mul, size_in_inch, self.scale)
+        size_in_pixels = tuple(map(mul, size_in_inch, self.scale))
         self.origin_in_inch = origin_in_inch if self.origin_in_inch is None else self.origin_in_inch
         self.size_in_inch = size_in_inch if self.size_in_inch is None else self.size_in_inch
         if (self.surface is None) or new_surface: