Class: HexaPDF::Writer

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

Overview

Writes the contents of a PDF document to an IO stream.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(document, io) ⇒ Writer

Creates a new writer object for the given HexaPDF document that gets written to the IO object.



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# File 'lib/hexapdf/writer.rb', line 61

def initialize(document, io)
  @document = document
  @io = io

  @io.binmode
  @io.seek(0, IO::SEEK_SET) # TODO: incremental update!

  @serializer = Serializer.new
  @serializer.encrypter = @document.encrypted? ? @document.security_handler : nil
  @rev_size = 0

  @use_xref_streams = false
end

Class Method Details

.write(document, io, incremental: false) ⇒ Object

Writes the document to the IO object and returns the last XRefSection written.

If incremental is true and the document was created from an existing PDF file, the changes are appended to a full copy of the source document.



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# File 'lib/hexapdf/writer.rb', line 51

def self.write(document, io, incremental: false)
  if incremental && document.revisions.parser
    new(document, io).write_incremental
  else
    new(document, io).write
  end
end

Instance Method Details

#write ⇒ Object

Writes the document to the IO object and returns the last XRefSection written.



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# File 'lib/hexapdf/writer.rb', line 76

def write
  write_file_header

  pos = xref_section = nil
  @document.trailer.info[:Producer] = "HexaPDF version #{HexaPDF::VERSION}"
  @document.revisions.each do |rev|
    pos, xref_section = write_revision(rev, pos)
  end

  xref_section
end

#write_incremental ⇒ Object

Writes the complete source document unmodified to the IO and then one revision containing all changes. Returns the XRefSection of that one revision.

For this method to work the document must have been created from an existing file.



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# File 'lib/hexapdf/writer.rb', line 92

def write_incremental
  @document.revisions.parser.io.seek(0, IO::SEEK_SET)
  IO.copy_stream(@document.revisions.parser.io, @io)
  @io << "\n"

  @rev_size = @document.revisions.current.next_free_oid
  @use_xref_streams = @document.revisions.parser.contains_xref_streams?

  revision = Revision.new(@document.revisions.current.trailer)
  @document.revisions.each do |rev|
    rev.each_modified_object {|obj| revision.send(:add_without_check, obj) }
  end
  _pos, xref_section = write_revision(revision, @document.revisions.parser.startxref_offset)

  xref_section
end