Class: Plugin::Thumbnailer::Service::InputImage

Inherits:
Object
  • Object
show all
Extended by:
Forwardable, PerfStats
Includes:
ClassLogging, PerfStats, MimeType
Defined in:
lib/httpthumbnailer/plugin/thumbnailer/service/images.rb

Constant Summary collapse

UpscaledError = 
Class.new RuntimeError

Class Method Summary collapse

Instance Method Summary collapse

Methods included from MimeType

#mime_type

Constructor Details

#initialize(image, thumbnailing_methods, edits) ⇒ InputImage 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 28

def initialize(image, thumbnailing_methods, edits)
  @image = image
  @thumbnailing_methods = thumbnailing_methods
  @edits = edits
end

Class Method Details

.from_blob(blob, thumbnailing_methods, edits, options = {}, &block) ⇒ Object 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 34

def self.from_blob(blob, thumbnailing_methods, edits, options = {}, &block)
  mw = options[:max_width]
  mh = options[:max_height]

  begin
    image = measure "loading original image" do
      image = measure "loading image form blob" do
        begin
          images =
            if mw and mh
              measure "loading image form blob with size hint", "#{mw}x#{mh}" do
                log.info "using max size hint of: #{mw}x#{mh}"
                Magick::Image.from_blob(blob) do |info|
                  # actual hint is 2x the max thumbnail dimensions so we don't loose too much quality
                  define('jpeg', 'size', "#{mw*2}x#{mh*2}")
                  define('jbig', 'size', "#{mw*2}x#{mh*2}")
                end
              end
            else
              measure "loading image form blob without size hint" do
                Magick::Image.from_blob(blob)
              end
            end
          begin
            image = images.shift
            begin
              if image.columns > image.base_columns or image.rows > image.base_rows
                log.warn "input image got upscaled from: #{image.base_columns}x#{image.base_rows} to #{image.columns}x#{image.rows}"
                if not options[:no_upscale_fix]
                  raise UpscaledError if options[:reload]
                  measure "downsampling input image to base size", "#{image.base_columns}x#{image.base_rows}" do
                    log.warn "downsampling input image to base size: #{image.base_columns}x#{image.base_rows}"
                    image = image.get do |image|
                      image.sample(image.base_columns, image.base_rows)
                    end
                  end
                end
              end
              image
            rescue
              image.destroy!
              raise
            end
          ensure
            images.each do |other|
              other.destroy!
            end
          end
        rescue UpscaledError
          log.warn "reloading input image without max size hint!"
          Service.stats.incr_total_images_reloaded
          mw = mh = nil
          retry
        end
      end
      image.get do |image|
        blob = nil

        log.info "loaded image: #{image.inspect.strip}"
        Service.stats.incr_total_images_loaded

        # clean up the image
        image.strip!
        image.properties do |key, value|
          log.debug "deleting user propertie '#{key}'"
          image[key] = nil
        end
        image
      end.get do |image|
        if mw and mh and not options[:no_downsample]
          f = image.find_downsample_factor(mw, mh)
          if f > 1
            measure "downsampling", image.inspect.strip do
              image = image.downsample(f)
              log.info "downsampled image by factor of #{f}: #{image.inspect.strip}"
              Service.stats.incr_total_images_downsampled
              image
            end
          end
        end
      end
    end
    image.get do |image|
      yield self.new(image, thumbnailing_methods, edits)
      true # make sure it is destroyed
    end
  rescue Magick::ImageMagickError => error
    raise ImageTooLargeError, error if error.message =~ /cache resources exhausted/
    raise UnsupportedMediaTypeError, error
  end
end

Instance Method Details

#_thumbnail(image, spec) ⇒ Object

Raises:



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 140

def _thumbnail(image, spec)
  spec = spec.dup
  # default background is white
  spec.options['background-color'] = spec.options.fetch('background-color', 'white').sub(/^0x/, '#')

  width = spec.width == :input ? @image.columns : spec.width
  height = spec.height == :input ? @image.rows : spec.height
  image_format = spec.format == :input ? @image.format : spec.format

  raise ZeroSizedImageError.new(width, height) if width == 0 or height == 0

  begin
    measure "generating thumbnail to spec", spec do
      image.get do |image|
        if image.alpha?
          measure "rendering image on background", image.inspect.strip  do
            log.info 'image has alpha, rendering on background'
            image.render_on_background(spec.options['background-color'])
          end
        else
          image
        end
      end.get do |image|
        spec.edits.each do |edit|
          log.debug "applying edit '#{edit}'"
          image = image.get do |image|
            measure "edit", edit do
              edit_image(image, edit.name, *edit.args, edit.options, spec)
            end
          end
        end
        image
      end.get do |image|
        log.debug "thumbnailing with method '#{spec.method} #{width}x#{height} #{spec.options}'"
        measure "thumbnailing with method", "#{spec.method} #{width}x#{height} #{spec.options}" do
          thumbnail_image(image, spec.method, width, height, spec.options)
        end
      end.get do |image|
        if image.alpha?
          measure "rendering thumbnail on background", image.inspect.strip do
            log.info 'thumbnail has alpha, rendering on background'
            image.render_on_background(spec.options['background-color'])
          end
        else
          image
        end
      end.get do |image|
        Service.stats.incr_total_thumbnails_created
        yield Thumbnail.new(image, image_format, spec.options)
      end
    end
  rescue Magick::ImageMagickError => error
    raise ImageTooLargeError, error.message if error.message =~ /cache resources exhausted/
    raise
  end
end

#edit_image(image, name, *args, options, spec) ⇒ Object 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 197

def edit_image(image, name, *args, options, spec)
  impl = @edits[name] or raise UnsupportedEditError, name

  # make sure we pass as many args as expected (filling with nil)
  args_no = impl.arity - 3 # for image, optioins and spec
  args = args.dup
  args.fill(nil, (args.length)...args_no)
  if args.length > args_no
    log.warn "extra arguments to edit '#{name}': #{args[args_no..-1].join(', ')}"
    args = args[0...args_no]
  end

  ret = impl.call(image, *args, options, spec)

  fail "edit '#{name}' returned '#{ret.class.name}' - expecting nil or Magick::Image" unless ret.nil? or ret.kind_of? Magick::Image
  ret or image
rescue PluginContext::PluginArgumentError => error
  raise EditArgumentError.new(name, error.message)
end

#height ⇒ Object 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 235

def height
  @image.base_rows
end

#thumbnail(spec, &block) ⇒ Object 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 133

def thumbnail(spec, &block)
  # we don't want to destory the input image after we have generated the thumbnail so we can generate another one
  @image.borrow do |image|
    _thumbnail(image, spec, &block)
  end
end

#thumbnail!(spec, &block) ⇒ Object 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 126

def thumbnail!(spec, &block)
  # it is OK if the image get's destroyed in the process
  @image.get do |image|
    _thumbnail(image, spec, &block)
  end
end

#thumbnail_image(image, method, width, height, options) ⇒ Object 



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 217

def thumbnail_image(image, method, width, height, options)
  impl = @thumbnailing_methods[method] or raise UnsupportedMethodError, method
  ret = impl.call(image, width, height, options)
  fail "thumbnailing method '#{name}' returned '#{ret.class.name}' - expecting nil or Magick::Image" unless ret.nil? or ret.kind_of? Magick::Image
  ret or image
rescue PluginContext::PluginArgumentError => error
  raise ThumbnailArgumentError.new(method, error.message)
end

#width ⇒ Object

We use base values since it might have been loaded with size hint and prescaled



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# File 'lib/httpthumbnailer/plugin/thumbnailer/service/images.rb', line 231

def width
  @image.base_columns
end