Class: Attached::Processor::Image

Inherits:
Base
  • Object
show all
Defined in:
lib/attached/processor/image.rb

Instance Attribute Summary collapse

Attributes inherited from Base

#attachment, #file, #options

Instance Method Summary collapse

Methods inherited from Base

process

Constructor Details

#initialize(file, options = {}, attachment = nil) ⇒ Image

Create a processor.

Parameters:

  • file - The file to be processed.

  • options - The options to be applied to the processing.

  • attachment - The attachment the processor is being run for.



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# File 'lib/attached/processor/image.rb', line 26

def initialize(file, options = {}, attachment = nil)
  super

  @path      = self.file.path

  @size      = options[:size]
  @quality   = options[:quality]
  @extension = options[:extension]

  @width, @height, @operation = @size.match(/(\d*)x?(\d*)(.*)/)[1..3] if @size

  @width     ||= options[:width]
  @height    ||= options[:height]
  @operation ||= options[:operation]

  @operation = case @operation
  when :decrease then '>'
  when :increase then '<'
  when :default  then '#'
  else @operation || '#'
  end

  @extension ||= self.attachment.extension

  @width     = Integer(self.width)  if self.width
  @height    = Integer(self.height) if self.height
end

Instance Attribute Details

#extension ⇒ Object (readonly)

Returns the value of attribute extension.



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# File 'lib/attached/processor/image.rb', line 10

def extension
  @extension
end

#height ⇒ Object (readonly)

Returns the value of attribute height.



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# File 'lib/attached/processor/image.rb', line 13

def height
  @height
end

#operation ⇒ Object (readonly)

Returns the value of attribute operation.



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# File 'lib/attached/processor/image.rb', line 15

def operation
  @operation
end

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/attached/processor/image.rb', line 9

def path
  @path
end

#quality ⇒ Object (readonly)

Returns the value of attribute quality.



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# File 'lib/attached/processor/image.rb', line 14

def quality
  @quality
end

#width ⇒ Object (readonly)

Returns the value of attribute width.



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# File 'lib/attached/processor/image.rb', line 12

def width
  @width
end

Instance Method Details

#process ⇒ Object

Helper function for calling processors.

Usage:

self.process



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# File 'lib/attached/processor/image.rb', line 68

def process

  result = Tempfile.new(["", self.extension])
  result.binmode

  begin

    parameters = []

    parameters << self.path

    if width and height
      parameters << case operation
      when '#' then "-resize #{width}x#{height}^ -gravity center -extent #{width}x#{height}"
      when '<' then "-resize #{width}x#{height}\\<"
      when '>' then "-resize #{width}x#{height}\\>"
      else          "-resize #{width}x#{height}"
      end
    end

    parameters << "-quality #{quality}" if quality

    parameters << result.path

    parameters = parameters.join(" ").squeeze(" ")

    `convert #{parameters} #{redirect}`

    raise Errno::ENOENT if $?.exitstatus == 127

  rescue Errno::ENOENT
    raise "command 'convert' not found: ensure ImageMagick is installed"
  end

  unless $?.exitstatus == 0
    raise Attached::Processor::Error, "must be an image file"
  end

  return result

end

#redirect ⇒ Object

Redirect output path.



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# File 'lib/attached/processor/image.rb', line 57

def redirect
  ">/dev/null 2>&1" if File.exist?("/dev/null")
end