relative to the current line of glyph from which a line leading ray such as the line leading ray 902 of fig9 can originate this same vertical position also is the vertical position at which a line leading ray originating from an immediately preceding line of glyphs ends that is a line leading ray representing the distance between current and immediately preceding lines originates at the line leading measure point of the immediately preceding line of glyphs and ends at the line leading measure point of the current line of glyphs to determine the line leading measure point the system uses the line leading metric and the line height calculated the system calculates the line leading measure point by locating the largest embox in the current line of glyphs and then determining the vertical position of this largest embox relative to the current line of glyphs the embox position depends on the dtp convention being used for roman dtp line definitions the top line of a current line of glyphs coincides with the base line of the emboxes in the immediately preceding line of glyphs and the bottom line of the current line of glyphs coincides with the baseline of the emboxes in the.