The routine gSetInterlineSpace() sets the current inter-line spacing factor for text blocks. Text blocks are positioned using gStartTextBlock(), and new lines are started by either calling gMoveToNextLine() or using the *N escape sequence within any of the string output routines.
The argument drpfac is a factor of the current character height (set by gSetCharSize()) by which each line of a text block is placed below the preceding line. The default drpfac of 2.0 sets each line to be positioned 2.0 * character height below the preceding line.
drpfac can be any real value, positive, negative or zero with the corresponding effect on the line spacing.
