Module: Tessel::PNG::Chunk

Defined in:
lib/tessel.rb

Class Method Summary collapse

Class Method Details

.write(io, type, data) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/tessel.rb', line 307

def write(io, type, data)
  type = String(type).b
  data = String(data).b
  raise ArgumentError, "PNG chunk type must be four bytes" unless type.bytesize == 4

  io << [data.bytesize].pack("N") << type << data << [Zlib.crc32(type + data)].pack("N")
end