Represents the "Ascent" 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 341.

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

Ascent is measured from the baseline upward in glyph space. It gives the maximum height of glyphs above the baseline, typically the top of a capital letter.

This value is used to calculate line spacing and to position text vertically within a layout region.