The PangoGlyphUnit type is used to store dimensions within Pango. Dimensions are stored in 1/PANGO_SCALE of a device unit. (A device unit might be a pixel for screen display, or a point on a printer.) PANGO_SCALE is currently 1024, and may change in the future (unlikely though), but you should not depend on its exact value. The PANGO_PIXELS() macro can be used to convert from glyph units into device units with correct rounding.