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module Paperclip
# Handles thumbnailing images that are uploaded.
class Thumbnail < Processor
attr_accessor :current_geometry, :target_geometry, :format, :whiny, :convert_options,
:source_file_options, :animated, :auto_orient
# List of formats that we need to preserve animation
ANIMATED_FORMATS = %w(gif)
# Creates a Thumbnail object set to work on the +file+ given. It
# will attempt to transform the image into one defined by +target_geometry+
# which is a "WxH"-style string. +format+ will be inferred from the +file+
# unless specified. Thumbnail creation will raise no errors unless
# +whiny+ is true (which it is, by default. If +convert_options+ is
# set, the options will be appended to the convert command upon image conversion
#
# Options include:
#
# +geometry+ - the desired width and height of the thumbnail (required)
# +file_geometry_parser+ - an object with a method named +from_file+ that takes an image file and produces its geometry and a +transformation_to+. Defaults to Paperclip::Geometry
# +string_geometry_parser+ - an object with a method named +parse+ that takes a string and produces an object with +width+, +height+, and +to_s+ accessors. Defaults to Paperclip::Geometry
# +source_file_options+ - flags passed to the +convert+ command that influence how the source file is read
# +convert_options+ - flags passed to the +convert+ command that influence how the image is processed
# +whiny+ - whether to raise an error when processing fails. Defaults to true
# +format+ - the desired filename extension
# +animated+ - whether to merge all the layers in the image. Defaults to true
def initialize(file, options = {}, attachment = nil)
super
geometry = options[:geometry].to_s
@crop = geometry[-1,1] == '#'
@target_geometry = options.fetch(:string_geometry_parser, Geometry).parse(geometry)
@current_geometry = options.fetch(:file_geometry_parser, Geometry).from_file(@file)
@source_file_options = options[:source_file_options]
@convert_options = options[:convert_options]
@whiny = options.fetch(:whiny, true)
@format = options[:format]
@animated = options.fetch(:animated, true)
@auto_orient = options.fetch(:auto_orient, true)
if @auto_orient && @current_geometry.respond_to?(:auto_orient)
@current_geometry.auto_orient
end
@source_file_options = @source_file_options.split(/\s+/) if @source_file_options.respond_to?(:split)
@convert_options = @convert_options.split(/\s+/) if @convert_options.respond_to?(:split)
@current_format = File.extname(@file.path)
@basename = File.basename(@file.path, @current_format)
end
# Returns true if the +target_geometry+ is meant to crop.
def crop?
@crop
end
# Returns true if the image is meant to make use of additional convert options.
def convert_options?
!@convert_options.nil? && !@convert_options.empty?
end
# Performs the conversion of the +file+ into a thumbnail. Returns the Tempfile
# that contains the new image.
def make
src = @file
filename = [@basename, @format ? ".#{@format}" : ""].join
dst = TempfileFactory.new.generate(filename)
begin
parameters = []
parameters << source_file_options
parameters << ":source"
parameters << transformation_command
parameters << convert_options
parameters << ":dest"
parameters = parameters.flatten.compact.join(" ").strip.squeeze(" ")
success = convert(parameters, :source => "#{File.expand_path(src.path)}#{'[0]' unless animated?}", :dest => File.expand_path(dst.path))
rescue Cocaine::ExitStatusError => e
raise Paperclip::Error, "There was an error processing the thumbnail for #{@basename}" if @whiny
rescue Cocaine::CommandNotFoundError => e
raise Paperclip::Errors::CommandNotFoundError.new("Could not run the `convert` command. Please install ImageMagick.")
end
dst
end
# Returns the command ImageMagick's +convert+ needs to transform the image
# into the thumbnail.
def transformation_command
scale, crop = @current_geometry.transformation_to(@target_geometry, crop?)
trans = []
trans << "-coalesce" if animated?
trans << "-auto-orient" if auto_orient
trans << "-resize" << %["#{scale}"] unless scale.nil? || scale.empty?
trans << "-crop" << %["#{crop}"] << "+repage" if crop
trans << '-layers "optimize"' if animated?
trans
end
protected
# Return true if the format is animated
def animated?
@animated && (ANIMATED_FORMATS.include?(@format.to_s) || @format.blank?) && identified_as_animated?
end
# Return true if ImageMagick's +identify+ returns an animated format
def identified_as_animated?
if @identified_as_animated.nil?
@identified_as_animated = ANIMATED_FORMATS.include? identify("-format %m :file", :file => "#{@file.path}[0]").to_s.downcase.strip
end
@identified_as_animated
rescue Cocaine::ExitStatusError => e
raise Paperclip::Error, "There was an error running `identify` for #{@basename}" if @whiny
rescue Cocaine::CommandNotFoundError => e
raise Paperclip::Errors::CommandNotFoundError.new("Could not run the `identify` command. Please install ImageMagick.")
end
end
end
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