<summary>
Gets common metrics for the font in design units.
These metrics are applicable to all the glyphs within a font,
and are used by applications for layout calculations.
</summary>
<param name="fontMetrics">Metrics structure to fill in.</param>
<summary> Gets common metrics for the font in design units. These metrics are applicable to all the glyphs within a font, and are used by applications for layout calculations. </summary> <param name="fontMetrics">Metrics structure to fill in.</param>