US 5,542,052 A · Applying traps to a printed page specified in a page description language format

Abstract

A trapping technique that accepts a Postscript or other page description language (PDL) file and outputs a file in PDL format having the correct traps. The input page is first divided into subportions, or tiles, and the tiles are individually processed by evaluating the input file in a corresponding dipping window. Each tile is then analyzed to determine the presence of boundaries or intersections between page objects or color regions. A trapping analyzer generates trap vectors in accordance with a set of desired trapping rules which take into account existing traps and the proximity of other page objects. In a preferred embodiment, the trap vectors are then convened to PDL form.

Claims17

Dependent claims

A method of electronically trapping a printed color page including a plurality of color regions, the method comprising the steps of:

(a) creating, according to a set of trapping rules, a proposed trap area for a color region of interest;
(b) determining a cutout from the proposed trap area if one or more color regions that do not overlap the proposed trap area are in such close proximity to the color region of interest that an undesirable trap would result without the modification;
and
(c) creating a resultant trap area for the color region of interest which is equivalent to the proposed trap area less the cutout.

1 more element

A method of electronically trapping a printed color page including a plurality of color regions, wherein some of the color regions include existing trap areas that were generated prior to determining a trap for a color region of interest, the method comprising the steps of:

(a) creating, according to a set of trapping rules, a proposed trap area for the color region of interest;
(b) comparing the proposed trap area to color regions to determine if there are any intersections between the proposed trap area and the color regions and, if one or more intersections are present, modifying the proposed trap area to exclude the color region or regions from the proposed trap area;
(c) comparing the proposed trap area to existing trap areas to determine if there are any intersections between the proposed trap and existing trap areas and, if one or more intersections are present, modifying one of the trap areas;
(d) creating a proximity area adjacent the proposed trap area for determining the proximity of color regions and comparing the proximity area to the color regions;
(e) further modifying the proposed trap area, based upon the proximity area, if one or more color regions are in such close proximity to the color region of interest that an undesirable trap would result without the modification;
and
(f) creating an existing trap area for the color region of interest which is equivalent to the proposed trap area less any modifications made to the proposed trap area.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application

08/188,246Filed 26 Jan 1994 · continuation in part

Priority

4 Mar 1991

Granted

30 Jul 1996

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

G06K 15/00
Arrangements for producing a permanent visual presentation of the output data
G06K 15/02
Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printers: using printers
G06K 15/129
By photographic printing , e.g. by laser printers: colour printing
G06K 15/1826
Adapting the print data to an output condition, e.g. object trapping: object trapping

Applying traps to a printed page specified in a page description language format

Life of this patent

Applying traps to a printed page specified in a page description language format

Life of this patent

Abstract

Claims17