Contents

require 'milton/derivatives/thumbnail/image'
require 'milton/derivatives/thumbnail/crop_calculator'

module Milton
  class Thumbnail < Derivative
    def process
      raise "target size must be specified for resizing" unless options.has_key?(:size)

      destination = Milton::Tempfile.path(settings[:tempfile_path], Milton::File.extension(@source.filename))
    
      # TODO: determine if this is neccessary or was just a problem w/ the
      # way we were calling convert
      # convert can be destructive to the original image in certain failure
      # cases, so copy it to a tempfile first before processing
      # source      = Milton::Tempfile.create(self.source, @source.options[:tempfile_path]).path
    
      if options[:crop]
        crop = CropCalculator.new(image, Image.from_geometry(options[:size]))
        size = crop.resizing_geometry
        conversion_options = %Q(-gravity #{crop.gravity} -crop #{crop.cropping_geometry})
      end
    
      # TODO: raise if the syscall fails
      Milton.syscall(%Q{convert #{source} -geometry #{size || options[:size]} #{conversion_options || ''} +repage "#{destination}"}) 
    
      # TODO: raise if the store fails
      file.store(destination)
    end

    protected
  
    # For speed, any derivatives less than 640-wide are made from a 
    # 640-wide version of the image (so you're not generating tiny
    # thumbnails from an 8-megapixel upload)
    def source
      image.width > 640 && Image.from_geometry(options[:size]).width < 640 ? 
        Thumbnail.process(@source, { :size => '640x' }, settings).path : @source.path
    end
  
    # Returns and memoizes an Image initialized from the file we're making a
    # thumbnail of
    def image
      @image ||= Image.from_path(@source.path)
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
citrusbyte-milton-0.3.1	lib/milton/derivatives/thumbnail.rb
citrusbyte-milton-0.3.2	lib/milton/derivatives/thumbnail.rb