Represents the "Descent" entry of the font descriptor object.

It is 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: 122, page 282.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 120, page 342.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 124, page 285.

Descent is measured from the baseline downward and is typically a negative number in glyph space. It gives the maximum depth of descending glyphs such as lowercase g, p, or y.

Together with Ascent and Leading, Descent determines the total vertical space a line of text occupies.