Class: Exif::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/exifparser.rb,
lib/exifparser/thumbnail.rb

Instance Method Summary collapse

Constructor Details

#initialize(file_handler) ⇒ Parser

create a new object. fpath is String.



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# File 'lib/exifparser.rb', line 102

def initialize(file_handler)
  @scanner = Exif::Scanner.new prepare_file(file_handler)
  @scanner.scan
  init_from_scanner
end

Instance Method Details

#[](tagname) ⇒ Object

search the specified tag values. return value is object of classes defined under Exif::Tag module.



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# File 'lib/exifparser.rb', line 150

def [](tagname)
  self.tag(tagname)
end

#[]=(tag, value) ⇒ Object

set the specified tag to the specified value. XXX NOT IMPLEMETED XXX



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# File 'lib/exifparser.rb', line 158

def []=(tag, value)
  # not implemented
end

#each(ifd = nil) ⇒ Object

execute given block with block argument being every tags defined in all the IFDs contained in the image.

if argument ifd is specified, every tags defined in the specified IFD are passed to block.

return value is object of classes defined under Exif::Tag module.

allowable arguments are:

  • :IFD0

  • :IFD1

  • :Exif

  • :GPS

  • :Interoperability

  • :MakerNote



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# File 'lib/exifparser.rb', line 223

def each(ifd=nil)
  if ifd
    @scanner.result[ifd].each{ |tag| yield tag }
  else
    [
      @IFD0,
      @IFD1,
      @Exif,
      @GPS,
      @Interoperability,
      @MakerNote
    ].flatten.each do |tag|
      yield tag
    end
  end
end

#init_from_scanner ⇒ Object 



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

def init_from_scanner
  @IFD0 = @scanner.result[:IFD0]
  @IFD1 = @scanner.result[:IFD1]
  @Exif = @scanner.result[:Exif]
  @GPS  = @scanner.result[:GPS]
  @Interoperability = @scanner.result[:Interoperability]
  @MakerNote = @scanner.result[:MakerNote]
  @thumbnail = @scanner.result[:Thumbnail]
end

#inspect ⇒ Object 



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# File 'lib/exifparser.rb', line 128

def inspect
  sprintf("#<%s filename=\"%s\" entries: IFD0(%d) IFD1(%d) Exif(%d) GPS(%d) Interoperability(%d) MakerNote(%d)>", self.class, @fpath, @IFD0.length, @IFD1.length, @Exif.length, @GPS.length, @Interoperability.length, @MakerNote.length)
end

#marshal_dump ⇒ Object 



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# File 'lib/exifparser.rb', line 240

def marshal_dump
  {scanner: Marshal.dump(@scanner)}
end

#marshal_load(marshaled) ⇒ Object 



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# File 'lib/exifparser.rb', line 244

def marshal_load marshaled
  @scanner = Marshal.load marshaled[:scanner]
  init_from_scanner
end

#orig_thumbnail ⇒ Object

extract the thumbnail image to dest. dest should respond to ‘<<’ method.



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# File 'lib/exifparser/thumbnail.rb', line 14

def thumbnail(dest)
  dest << @thumbnail
end

#prepare_file(handler) ⇒ Object 



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# File 'lib/exifparser.rb', line 118

def prepare_file(handler)
  if handler.is_a? String
    @fpath = handler
    File.open(handler, "rb")
  elsif handler.is_a?(StringIO) || handler.is_a?(File)
    @fpath = 'dummy_file'
    handler
  end
end

#tag(tagname, ifd = nil) ⇒ Object

search tag on the specific IFD



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# File 'lib/exifparser.rb', line 142

def tag(tagname, ifd=nil)
  search_tag(tagname, ifd)
end

#tag?(tagid) ⇒ Boolean

return true if specified tagid is defined or has some value.

Returns:

  • (Boolean) 


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# File 'lib/exifparser.rb', line 135

def tag?(tagid)
  search_tag(tagid) ? true : false
end

#tags(ifd = nil) ⇒ Object

return all the tags in the image.

if argument ifd is specified, every tags defined in the specified IFD are passed to block.

return value is object of classes defined under Exif::Tag module.

allowable arguments are:

  • :IFD0

  • :IFD1

  • :Exif

  • :GPS

  • :Interoperability

  • :MakerNote (if exist)



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# File 'lib/exifparser.rb', line 192

def tags(ifd=nil)
  if ifd
    @scanner.result[ifd]
  else
    [
      @IFD0,
      @IFD1,
      @Exif,
      @GPS,
      @Interoperability,
      @MakerNote
    ].flatten
  end
end

#thumbnail ⇒ Object

redefine method.



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# File 'lib/exifparser.rb', line 166

def thumbnail(dest)
  dest << @thumbnail
end

#thumbnail_size ⇒ Object

return the size of the thumbnail image



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# File 'lib/exifparser.rb', line 173

def thumbnail_size
  @thumbnail.size
end