18.30.1  Example 

     CALL TDTEXT('TOP','My graph',' ')
Puts a title at the top of the graph.
     CALL TDTEXT('BOTTOM','X Axes',' ')
Puts a title at the bottom of the graph.
     CALL TDTEXT(' ','More on the bottom',' ')
Then puts another line ender the previous one.
     CALL TDTEXT('DATA','This is at location 5,1.8',' ',5.,1.8)
Puts a title left justified at the data locations 5.0,1.8
     CALL TDTEXT('DATA,CENTER','This is at location 5,1.8',' ',5.,1.8)
Puts a title centered at the data locations 5.0,1.8