picturefill-rails.rb

  def pf(path)
    picturefill(path, "AltText") do
     b = path.scan(/(^.*)\.(jpg|png|gif)/).flatten
     sizes = {
      :small           => "#{b[0]}_small.#{b[1]}",
      :medium          => "#{b[0]}_medium.#{b[1]}",
      :medium_high_dpi => "#{b[0]}_medium_high_dpi.#{b[1]}",
      :large           => "#{b[0]}_large.#{b[1]}",
      :large_high_dpi  => "#{b[0]}_large_high_dpi.#{b[1]}"
     }
     present_sizes = {}

     sizes.each do |k,v|
      present_sizes[k] = Rails.application.assets.find_asset(v).nil? ? nil : v
     end

     image(image_path("#{b[0]}_small.#{b[1]}")) if present_sizes[:small] 
     image(image_path("#{b[0]}_medium.#{b[1]}"), :min => 400) if present_sizes[:medium] 
     image(image_path("#{b[0]}_medium_high_dpi.#{b[1]}"), :min => 400, :ratio => 1.5) if present_sizes[:medium_high_dpi] 
     image(image_path("#{b[0]}_medium_high_dpi.#{b[1]}"), :min => 400, :ratio => 1.5, :webkit => true) if present_sizes[:medium_high_dpi] 
     image(image_path("#{b[0]}_large.#{b[1]}"), :min => 1000) if present_sizes[:large] 
     image(image_path("#{b[0]}_large_high_dpi.#{b[1]}"), "(min-width: 1000px) and (min-device-pixel-ratio: 1.5)") if present_sizes[:large_high_dpi] 
    end
  end