, the ascenders and descenders and the distances between the text lines are specified. The unit originates from classical typesetting and has been adopted, slightly modified, in electronic typesetting. One Didot point (1dp) is equal to 1/2660 m or 0.3759 mm. 1 mm is therefore 2.66 dp. In electronic typesetting, the "dot" is based on the inch
and is abbreviated "pt" or "bp". One point (1pt) is equal to 1/72 inch or 0.3527 mm. 1 mm is therefore 2.835 pt.In addition to the unit didot point, classical typesetting also used the cicero, which corresponds to 12 didot points
. The cicerois not used in electronic typesetting. The
English unit of measurement pica is also used, which is also used for the type width. One pica is equal to 12 pica points, 1/6 inch or 0.351 mm.
Another unit used in typesetting that is based on the didot point is the twip (twentieth of a point). A twip is equal to 1/20 Didot point, 1/1440th (72 x 20) of an inch, or 1/567th of a centimeter.