class Magick::Image

def resize_to_fit(cols, rows = nil)

(Thanks to Robert Manni!)
Convenience method to resize retaining the aspect ratio.
def resize_to_fit(cols, rows = nil)
  rows ||= cols
  change_geometry(Geometry.new(cols, rows)) do |ncols, nrows|
    resize(ncols, nrows)
  end
end