Class: MiniMagick::Image

Inherits:
Object
  • Object
show all
Defined in:
lib/mini_magick.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input_path, tempfile = nil) ⇒ Image 



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# File 'lib/mini_magick.rb', line 64

def initialize(input_path, tempfile=nil)
  @path = input_path
  @tempfile = tempfile # ensures that the tempfile will stick around until this image is garbage collected.

  # Ensure that the file is an image
  # might as well collect some information here.
  #
  get_file_info(input_path)

end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(symbol, *args) ⇒ Object

If an unknown method is called then it is sent through the morgrify program Look here to find all the commands (www.imagemagick.org/script/mogrify.php)



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# File 'lib/mini_magick.rb', line 130

def method_missing(symbol, *args)
  args.push(@path) # push the path onto the end
  run_command("mogrify", "-#{symbol}", *args)
  self
end

Instance Attribute Details

#output ⇒ Object (readonly)

Returns the value of attribute output.



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# File 'lib/mini_magick.rb', line 15

def output
  @output
end

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/mini_magick.rb', line 13

def path
  @path
end

#tempfile ⇒ Object (readonly)

Returns the value of attribute tempfile.



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# File 'lib/mini_magick.rb', line 14

def tempfile
  @tempfile
end

Class Method Details

.from_blob(blob, extension = nil) ⇒ Object 



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# File 'lib/mini_magick.rb', line 20

def from_blob(blob, extension=nil)
  begin
    tempfile = ImageTempFile.new("minimagick#{extension}")
    tempfile.binmode
    tempfile.write(blob)
  ensure
    tempfile.close
  end
  
  return self.new(tempfile.path, tempfile)
end

.from_file(image_path) ⇒ Object

Use this if you don’t want to overwrite the image file



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# File 'lib/mini_magick.rb', line 33

def from_file(image_path)
  File.open(image_path, "rb") do |f|
    self.from_blob(f.read, File.extname(image_path))
  end
end

Instance Method Details

#[](value) ⇒ Object

For reference see www.imagemagick.org/script/command-line-options.php#format



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# File 'lib/mini_magick.rb', line 76

def [](value)
  # Why do I go to the trouble of putting in newlines? Because otherwise animated gifs screw everything up
  case value.to_s
  when "format"
    if !(@image_info && @image_hash == cksum(@path))
get_file_info(@path)
  end
  @image_info[:format]

  when "height"
    if !(@image_info && @image_hash == cksum(@path))
get_file_info(@path)
  end
  @image_info[:height]

  when "width"
    if !(@image_info && @image_hash == cksum(@path))
get_file_info(@path)
  end
    @image_info[:width]

  when "original_at"
    # Get the EXIF original capture as a Time object
    Time.local(*self["EXIF:DateTimeOriginal"].split(/:|\s+/)) rescue nil
  when /^EXIF\:/i
    run_command('identify', '-format', "\"%[#{value}]\"", @path).chop
  else
    run_command('identify', '-format', "\"#{value}\"", @path).split("\n")[0]
  end
end

#cksum(input_path) ⇒ Object

Instance Methods



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# File 'lib/mini_magick.rb', line 42

def cksum(input_path)
   run_command("cksum", @path.gsub(/\[\d+\]$/,"")).split(/\s/)[0]
end

#combine_options(&block) ⇒ Object

You can use multiple commands together using this method



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# File 'lib/mini_magick.rb', line 137

def combine_options(&block)
  c = CommandBuilder.new
  block.call c
  run_command("mogrify", *c.args << @path)
end

#format(format) ⇒ Object

This is a ‘special’ command because it needs to change @path to reflect the new extension



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# File 'lib/mini_magick.rb', line 108

def format(format)
  run_command("mogrify", "-format", format, @path)
  @path = @path.sub(/(\.\w+)?$/, ".#{format}")
  
  raise "Unable to format to #{format}" unless File.exists?(@path)
end

#format_option(format) ⇒ Object

Outputs a carriage-return delimited format string for Unix and Windows



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# File 'lib/mini_magick.rb', line 149

def format_option(format)
  windows? ? "#{format}\\n" : "#{format}\\\\n"
end

#get_file_info(input_path) ⇒ Object 



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# File 'lib/mini_magick.rb', line 46

def get_file_info(input_path)
  @image_hash = cksum(@path)
  @image_info_string = run_command("identify", "-format", "|s:%s|m:%m|h:%h|w:%w|%[EXIF:*]\n", @path)

  # save the hash of the file, so we can validate it again.

  mm=@image_info_string.match(/^\|s\:(\d+)\|m\:([^\|]*)\|h\:(\d+)\|w\:(\d+)\|(EXIF)?(.*)/)
  if mm
    @image_info = {}
    @image_info[:format] = mm[2];
    @image_info[:height] = mm[3];
    @image_info[:width] = mm[4];
    @image_info[:exif] = mm[5];
  end

end

#run_command(command, *args) ⇒ Object 



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# File 'lib/mini_magick.rb', line 153

def run_command(command, *args)
  args.collect! do |arg|
    arg = arg.to_s
    arg = %|"#{arg}"| unless arg[0] == ?- # values quoted because they can contain characters like '>', but don't quote switches          
    arg
  end

  @output = `#{command} #{args.join(' ')}`

  if $? != 0
    raise MiniMagickError, "ImageMagick command (#{command} #{args.join(' ')}) failed: Error Given #{$?}"
  else
    @output
  end
end

#to_blob ⇒ Object

Give you raw data back



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# File 'lib/mini_magick.rb', line 124

def to_blob
  File.read @path
end

#windows? ⇒ Boolean

Check to see if we are running on win32 – we need to escape things differently



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# File 'lib/mini_magick.rb', line 144

def windows?
  !(RUBY_PLATFORM =~ /win32/).nil?
end

#write(output_path) ⇒ Object

Writes the temporary image that we are using for processing to the output path



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# File 'lib/mini_magick.rb', line 116

def write(output_path)
  FileUtils.copy_file @path, output_path
  unless @image_info && @image_hash == cksum(@path)  # skip if we have the same file and we've read it
        run_command "identify", output_path # Verify that we have a good image
  end
end