Resizing an image to a given rectangle maintaining aspect ratio

gistfile1.rb

def fit_dimensions( original, target )
	original_ratio = original[:height].to_f / original[:width].to_f
	target_ratio   = target[:height].to_f / target[:width].to_f
	result = target.clone
	case original_ratio <=> target_ratio
	when -1 then result[:height] = target[:width].to_f * original_ratio 
	when  1 then result[:width]  = target[:height].to_f / original_ratio 
	end		
	return result
end