Automatic trapping of drop shadows

Abstract

Methods, program products and systems for automatically trapping drop shadows. For at least one segment incident to an atomic region which includes a drop shadow, and for each side of the segment, determining a first flattened color of the side's incident atomic region, and if the atomic region includes a drop shadow, additionally determining a second flattened color omitting the color of the drop shadow. An effective neutral density from the side's first flattened color is determined and, if the side has a second flattened color, the side's second flattened color. The two atomic regions incident to the segment are trapped based upon the effective neutral densities for the respective sides.

Description

technical field [0001] The present disclosure relates to automatically determining printing traps. Background technique [0002] Computer graphics illustrations are often composed of various types of primitives. Types of primitives include: rasterized graphics, glyphs, vector strokes, vector fills, image masks, soft masks, and gradients. Primitives typically include paths that define the boundaries of the primitive. Primitives can interact with each other (eg, through shading). Thus, unless otherwise indicated, any illustrations discussed are computer graphics illustrations. [0003] When printing an illustration, a printing device may use multiple printing units (eg, individual printing plates in a multi-plate printing apparatus) to print the colors in the illustration. If the printing unit is not properly aligned, it is characteristic that a colorless gap will appear between adjacent parts of the illustration having different colors. The gap may also grow if during th...

AI Technical Summary

Problems solved by technology

In some cases, such as for diagrams that include cast shadows, previous automatic trapping techniques produced undesired results

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