photogriffy.net/app/helpers/screenshot_helper.rb

module ScreenshotHelper
  def size_calc (fwidth, fheight, max = 500)
    ##
    ## Image size calculator function.
    ## Inputs: 
    ## fwidth = original file width
    ## fheight = original file height
    ## max = maximum desired dimension, default = 500px
    ## Outputs:
    ## Size array of 'width' and 'height'
    ##
    
    if (fwidth >= fheight) then
    	if (fwidth >= max) then
    		width = max
    		height = ((fheight / fwidth.to_f) * max).to_i
    	else
    		width = fwidth
    		height = fheight
    	end
    elsif (fheight > fwidth) then
    	if (fheight > max) then
    		height = max
    		width = (( fwidth / fheight.to_f ) * max).to_i
    	else
    		height = fheight
    		width = fwidth
    	end
    else 
      width = fwidth
      height = fheight
    end
    
    return [width, height]
  end
end