-BwDrawer.read_stack = d3.stack()
- .value(function(d) { return d.read_values; });
-BwDrawer.write_stack = d3.stack()
- .value(function(d) { return d.write_values; });
+BwDrawer.read_stack = d3.layout.stack()
+ .values(function(d) { return d.read_values; });
+BwDrawer.write_stack = d3.layout.stack()
+ .values(function(d) { return d.write_values; });