8.5.3 Computing Character String Sizes
Xlib provides functions that you can use to compute the width,
the logical extents,
and the server information about 8-bit and 2-byte text strings.
The width is computed by adding the character widths of all the characters.
It does not matter if the font is an 8-bit or 2-byte font.
These functions return the sum of the character metrics, in pixels.
To determine the width of an 8-bit character string, use
XTextWidth().
To determine the width of a 2-byte character string, use
XTextWidth16().
Christophe Tronche, ch@tronche.com