Page:FORTRAN IV enhanced character graphics (IA fortranivenhance5003wolc).pdf/7

 BLOCK DATA

The BLOCK DATA subprogram contains the data to draw the Hershey characters and the plotting symbols. Variables which need to be saved and the initialization of the computer character set are also included in this subprogram.

IV. OPERATION OF THE SUBROUTINE SYMBOL.

The subroutine is accessed by a FORTRAN subroutine call:

CALL SYMBOL (X,Y,HEIGHT,TEXT,THETA,N)

The input string TEXT may contain the 47 FORTRAN characters for text and 11 non-FORTRAN characters which are used for control information. The control characters may be varied at implementation time by changing the associated data card in the BLOCK DATA subprogram. The current significance of the control characters is as follows: