-ADD_INTERFACE(Line_interface, "line-interface",
- "Generic line objects. Any object using lines supports this. ",
+ADD_INTERFACE (Line_interface, "line-interface",
+ "Generic line objects. Any object using lines supports this. Normally,"
+ "you get a straight line. If @code{dash-period} is defined, a dashed line is "
+ "produced; the length of the dashes is tuned with "
+ "@code{dash-fraction}. If the latter is set to 0, a dotted line is "
+ "produced. If @code{dash-fraction} is negative, the line is made "
+ "transparent.",
+