Page:FORTRAN IV enhanced character graphics (IA fortranivenhance5003wolc).pdf/8

 Mathematical and special symbols are accessed by the control code !^. Since there are no italic greek characters this region of the table has been used to provide the 48 special characters and mathematical symbols.

If no control information is provided in the input string, the default options of simplex upper case letters is supplied so that the program is 'downward compatible'. Up to six backspaces are allowed for that aligned subscripts and superscripts can be in the program so generated.

V. GRAPHICAL OUTPUT. The output of the test program is shown in Figs. 1. and 2. These figures show the range of characters and plotting symbols available. The program listings are in Appendix I. In Appendix II a special Fortran V version suitable for the UNIVAC 1100 is given.

For information on how to produce a desired character, reference should be made to the character repertory of Fig. 1. Each of the characters in the lines starting with numerics are produced by the corresponding FORTRAN character preceded by the appropriate control character (s) as shown to the right of the line. Characters in the lines beginning with alphabetic characters or mathematical and special symbols are produced by the control characters to the right of the line followed by the corresponding sequential alphabetic character. Thus for example the graphic sequence Σ Θ is produced by the string arugment to SYMBOL of '!^S^T', since S and T are the 19th and 20th letters of the alphabet and Σ and Θ are the 19th and 20th graphics in the line governed by control code !^. Reference to the test program in Appendix I, which produced Figs. 1 and 2, will show in detail the calling sequence for the graphic and plotting symbols shown in the figures.

VI. STEPS FOR IMPLEMENTATION.

(1) Install the appropriate version of the function IFLD at line SYM00800 of SYMBOL and at line TST00090 of the test program. Univac 1100 machines have one's complement arithmetic, while the IBM 360/370, and DEC PDP-10 and PDP-11 have two's complement arithmetic.

(2) Install the selected special characters at line DAT0830 of BLOCK DATA.

(3) Change the DATA statement at line DAT00840 of BLOCK DATA. appropriate to the computer in use. (IOUT is the Fortran unit for line printer output.) NWORD and NCHAR are in general the number of bits per word and number of bits per character respectively.

(4) Provide a subroutine PLOT to generate plotter output for your plotting device.

The following versions of the program have been tested and are included to assist user implementation.

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