Represents the "RD" entry of the free text annotation object.

It is an optional entry defined as part of the PDF 1.6 specification.

It contains a RectangleElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 174, page 397.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 177, page 481.

The rect difference array contains four numbers specifying insets from the annotation Rect: left, top, right, and bottom. Text is rendered within the inset rectangle, leaving the outer margin for border and callout drawing.