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

Returns a new instance of 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