By default the cropping is weighted at the center of the Geometry. I want it to be north west, so I came up with this dirty hack for setting the gravity to north west:
```ruby
module Paperclip
# Defines the geometry of an image.
class Geometry
def cropping dst, ratio, scale
if ratio.horizontal? || ratio.square?
#"%dx%d+%d+%d" % [ dst.width, dst.height, 0, (self.height * scale - dst.height) / 2 ]
"%dx%d+%d+%d" % [ dst.width, dst.height, 0, 0 ]
else
#"%dx%d+%d+%d" % [ dst.width, dst.height, (self.width * scale - dst.width) / 2, 0 ]
"%dx%d+%d+%d" % [ dst.width, dst.height, 0, 0 ]
end
end
end
end
```