Represents the "XStep" entry of the type 1 pattern dictionary object.

It is a required entry defined as part of the PDF 1.0 specification.

It contains a double representing a PDF numeric object.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 75, page 175.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 74, page 218.

XStep defines the horizontal offset in pattern space between successive repetitions of the pattern cell. It may differ from the width of the BBox; if larger, a gap appears between tiles; if smaller, tiles overlap.