gistfile1.rbx

class Image
  attr_reader :src
  
  def self.zoom_crop(src, max_width, max_height, out="thumbs/")    
    # Image details
    new(src).zoom_crop(max_width, max_height, out)
  end
  def initialize(src)
    @src = src    
  end
  def zoom_crop(max_width, max_height, out)
    opts = []
    opts << (horizontal? ? resize_horizontal(max_width, max_height) : resize_vertical(max_width, max_height))
    opts << "-crop #{max_width}x#{max_height}+0+0"
    
    cmd = "mogrify #{opts.join(" ")} +repage -path #{out} #{src}"
    `#{cmd}`
  end
  def resize_vertical(forced_width, forced_height)
    new_width = forced_width
    new_height = new_width * aspect_ratio
        
    [
      "-gravity 'north'",
      "-resize #{new_width}x#{new_height}"
    ]
  end
  def resize_horizontal(forced_width, forced_height)
    new_height = forced_height
    new_width = new_height * aspect_ratio
    
    [
      "-gravity Center",
      "-resize #{new_width}x#{new_height}"
    ]
  end
  def write(out)
    image.write(out)
  end
  def aspect_ratio
    @aspect_ratio ||= (vertical? ? (height/width) : (width/height)).to_f
  end
  def horizontal?
    @horizontal ||= (width > height)
  end
  def vertical?
    @vertical ||= (width <= height)
  end
  def width
    @width ||= info.split("x")[0].to_f
  end
  def height
    @height ||= info.split("x")[1].to_f
  end
  def info
    @info ||= `identify #{src} | awk '{print $3}'`
  end
  def src
    @src
  end
end

# Quick test
output_dir = File.join(File.dirname(__FILE__), "thumbs")
Dir[File.join(File.dirname(__FILE__), "images")+"/*"].each do |path|
  Image.zoom_crop(path, 150,130, output_dir)
end