forked from thoughtbot/paperclip
/
thumbnail.rb
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/
thumbnail.rb
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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
# 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
def initialize file, options = {}
super
geometry = options[:geometry]
@file = file
@crop = geometry[-1,1] == '#'
@target_geometry = Geometry.parse geometry
@current_geometry = Geometry.from_file @file
@convert_options = options[:convert_options]
@whiny = options[:whiny].nil? ? true : options[:whiny]
@format = options[:format]
@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?
not @convert_options.blank?
end
# Performs the conversion of the +file+ into a thumbnail. Returns the Tempfile
# that contains the new image.
def make
src = @file
dst = Tempfile.new([@basename, @format].compact.join("."))
dst.binmode
command = <<-end_command
"#{ File.expand_path(src.path) }[0]"
#{ transformation_command }
"#{ File.expand_path(dst.path) }"
end_command
begin
success = Paperclip.run("convert", command.gsub(/\s+/, " "))
rescue PaperclipCommandLineError
raise PaperclipError, "There was an error processing the thumbnail for #{@basename}" if @whiny
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 = "-resize \"#{scale}\""
trans << " -crop \"#{crop}\" +repage" if crop
trans << " #{convert_options}" if convert_options?
trans
end
end
end