| 摘要 |
A system is disclosed which allows for tracing an electronic document within an electronic publication. A message identifier is associated with the electronic document. The message identifier is transformed into a binary format. Drawing instructions are provided in the electronic page description of the electronic document to encode each bit of the binary format as a unique geometrical shape. The plurality of geometrical shapes for all the bits define a mark. The drawing instructions are provided such that the geometrical shapes are invisible and/or overlaid/overlapped. The modified electronic document is then added to the electronic publication. To trace the electronic document, the electronic page description of the electronic publication is sent to an interpreter to extract the geometrical shapes and/or their positions and decode the message identifier. |
