Method of trapping graphical objects in a desktop publishing program

• US 5,666,543 A
• Filed: 03/23/1994
• Issued: 09/09/1997
• Est. Priority Date: 03/23/1994
• Status: Expired due to Term

• Current Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Gartland, Richard A.
• Primary Examiner(s): Feild, Joseph H.
• Application Number:
  US08/216,729
• Time in Patent Office: 1,266 Days
• Field of Search: 395/145-148, 395/131, 395/133-135, 395/116-117, 395/109, 395/779, 395/780, 395/782, 395/783, 395/784, 395/785, 395/787, 395/788-790, 345/115, 345/136, 345/149-150, 345/185-191
• US Class Current: 715/205
• CPC Class Codes: G06F 40/103 Formatting, i.e. changing of presentation of documents automatic justification G06F40/189; automatic line break hyphenation G06F40/191
• CPC Class Codes: G06K 15/1826 Object trapping

Abstract

The publication prolog of a PostScript page description language (PDL) or other PDL file is modified to create traps within an interpreter or raster image processor (RIP). The publication prolog is modified to provide the trapping instructions to the RIP, while the script is sent unmodified to the RIP. In a preferred embodiment, modification of the publication prolog to instruct the RIP includes creating a directory of the color objects in the publication, and trapping the color objects in the publication using the directory. Thereafter, the modified publication prolog and script are sent to the RIP and trap areas are created as the publication is rendered.

Claims

1. A method in a raster image processor to trap page objects, comprising:

receiving a page prolog, comprising page description language (PDL) instructions executable by a raster image processor (RIP) to trap page objects;

receiving a page script, comprising PDL instructions describing a plurality of page objects and executable by the RIP; and

executing the prolog PDL instructions to trap an object described by the script PDL instructions.

2. The method of claim 1, further comprising executing the prolog PDL instructions to trap each object described by the script PDL instructions.

3. The method of claim 1, further comprising:

executing script PDL instructions by the RIP to draw a current object; and

executing prolog PDL instructions by the RIP to;

store the current object to an object directory;

retrieve an object from the object directory as a background object; and

evaluate trapping criteria to determine whether to trap the current object against the background object, and if the current object is to be trapped against the background object, determine a color and position for a trap and draw the trap.

4. A computer program stored on a computer-readable medium, comprising instructions for causing a raster image processor to trap page objects, comprising:

a page prolog, comprising page description language (PDL) instructions executable by a raster image processor (RIP),

wherein a RIP receives the page prolog and a page script, the page script comprising PDL instructions describing a plurality of page objects and executable by the RIP, and executes the prolog PDL instructions to trap an object described by the script PDL instructions.

5. The computer program of claim 4, wherein the prolog PDL instructions further cause the RIP to:

execute script PDL instructions to draw a current object; and

execute prolog PDL instructions to;

store the current object to an object directory;

retrieve an object from the object directory as a background object; and

evaluate trapping criteria to determine whether to trap the current object against the background object, and if the current object is to be trapped against the background object, determine a color and position for a trap and draw the trap.

6. A computer program stored on a computer-readable medium, comprising instructions for causing a computer to:

send a page prolog to a raster image processor (RIP); and

send a page script to the RIP, the page script comprising page description language (PDL) instructions describing a plurality of page objects, wherein the page prolog comprises page description language (PDL) instructions for causing the RIP to trap a page object described by the script PDL instructions.

7. The computer program of claim 6, wherein the prolog PDL instructions further cause the RIP to:

execute script PDL instructions to draw a current object; and

execute prolog PDL instructions to;

store the current object to an object directory;

retrieve an object from the object directory as a background object; and

evaluate trapping criteria to determine whether to trap the current object against the background object, and if the current object is to be trapped against the background object, determine a color and position for a trap and draw the trap.