Data structure for a document processing system

[54] DATA STRUCTURE FOR A DOCUMENT PROCESSING SYSTEM

[75] Inventors: Aran K. Agarwal, Chelmsford;

Suzanne C. Knapp, Lowell; David R.
Lakness, Chelmsford, all of Mass.

[73] Assignee: Wang Laboratories, Inc., Lowell,
Mass.

[21] Appl. No.: 658,952
[22] Filed: Oct. 9,1984

[51] Int. CL> G06F 15/40; G06F 7;

G06F 00; G06F 12/00

[52] U.S. CI 364/200; 364/300

[58] Field of Search ... 364/200 MS File, 900 MS File,

364/300 MS File

[56] References Cited

U.S. PATENT DOCUMENTS

4,068,300 1/1978 Bachman 364/200

4,408,181 10/1983 Nakayama 364/900

4,454,576 6/1984 Mclnroy et al 364/200

4,464,730 9/1984 Lawrence et al 364/900

4,503,515 3/1985 Cuan et al 364/900

4,513,391 4/1985 Maddock 364/900

4,539,653 9/1985 Barlett et al 364/900

4,553,206 11/1985 Smutek et al 364/300

4,553,860 U/1985 Imaizumi et al 364/900

4,633,430 12/1986 Cooper 364/900

Primary Examiner—Raulfe B. Zache
Assistant Examiner—William G. Niessen
Attorney, Agent, or Firm—Michael H. Shanahan

[57] ABSTRACT

A data structure for use in a document processing system corresponds to a document comprised of one or more Pages. Each Page is subdivided into one or more nonoverlapping Areas, each Area in turn being comprised of one or more types of Layers. Each Layer type is expressive of a particular type of information such as text or graphics information. Different Layer types may be superimposed to comprise the contents of an Area.

12 Claims, 13 Drawing Figures