9.3 Font Metrics
- Ascent.
The distance from the baseline to the top of most characters.
Note that in some cases characters may extend above the ascent.
- Descent.
The distance from the baseline to the bottom of most characters. Note that
in some cases characters may extend below the descent.
- Leading.
The amount of space, in pixels, to leave between the descent of one line of
text and the ascent of the next line. This metrics is not specified in the
current file format; instead, the font rendering engine calculates a
reasonable leading value based on the other font metrics.
- Horizonal leading.
The amount of space, in pixels, to leave horizontally between the left and
right edges of two adjacent glyphs. The device width field determines
the effective leading value that is used to render the font.
An illustration of how the various font metrics apply to characters.