Interface Metrics

The font's ascent above the baseline in whole px at the measured size — GDI's tmAscent, which is what Excel lays text out with (the OS/2 winAscent, hinted where the font has a VDMX table).

The baseline's offset from the top of a lineHeight box, in px: where a renderer that paints the line as a box (a CSS line box) puts the alphabetic baseline.

The font's descent below the baseline in whole px — GDI's tmDescent (OS/2 winDescent).

The leading in px: the room in lineHeight beyond the ascent and descent.

The line pitch in px — what a line of this text advances by: ascent plus descent plus lineGap.