JavaScript image reseize and crop, inline-onload, imgur.com optimized

gistfile1.coffee

window.resize_crop = (img) ->

  org = new Image()
  org.src = img.src

  org.onload = ->
    j_img = $(img)
    src = @src

    img_w = parseInt j_img.css "width"
    img_h = parseInt j_img.css "height"

    if /imgur\.com\/(\w+)/.test(src)
      img_url = RegExp.$1
      img_url = img_url.replace(/(\w)$/, "")
      img_ext = RegExp.$1
      img_url += img_ext  unless /[sml]/.test(img_ext)
      switch 
        when img_w < 90 then img_url += 's'
        when img_w < 320 then img_url += 'm'
        else img_url += 'l'
      
      src = src.replace(/\/[^\/]+$/, '/'+img_url+'.jpg')

    target = (if parseInt(@width) / img_w > parseInt(@height) / img_h then "height" else "width")
    clip = """clip:rect(0px #{img_w}px #{img_h}px 0px);"""

    if target is "height"
      aspect = @width / @height
      if aspect > 1
        shift_x = parseInt((img_w * aspect - img_w) / 2)
        clip = """clip:rect(0px #{img_w + shift_x}px #{img_h}px #{shift_x}px); margin-left:-#{shift_x}px;"""

    img_html = """<img style="#{target}:#{j_img.css(target)}; position:absolute; top:0px; left:0px; #{clip}" src="#{src}" />"""
    j_img.replaceWith """<div style="border:1px solid red; position:relative; display:inline-block; #{j_img.attr('style')}">#{img_html}</div>"""

# <img src="http://i.imgur.com/QFTMU.jpg" style="width:200px; height:200px;" onload="resize_crop(this)" />