Page:NBS Technical Note 11176 (1983) (IAutilityprogramsf1176dick).djvu/16

 Lines 1000-1460: HERSHEY VECTOR INPUT

This section contains the routines to input a character using the vectors listed by Holcott and Nilsenrath. Initially, however, the user is given the choice to input these vectors or to enter the character using the character edit routines of the 5000 section. The directions given for the Hershey coordinate input indicate the procedure to follow to enter the data. Line 1100 is used to eliminate the initialization of the character number, L, if the font is being edited or modified. Line 1120 branches to the subroutine that draws the hires graphics that illustrates the character as it is input. The appropriate x- and y-offsets are entered using the GET command of Applesoft to input a character string. Inclusion in the string of the left arrow requires the re-entry of the entire string. Entering a space for the horizontal input signals a change of pen position for the following coordinate move only (the equivalent of:-64 0: in the Wolcott notation). Entering the symbol, /, for the horizontal coordinate signals the end of the character (:-64 -64:), and enters the appropriate vectors to advance the pen to the location of the right marker. The first two vectors input indicate the left and right markers respectively, and are used to determine the character width, W, in line 1350. The previous x and y coordinates are stored in the variables XT and YT and are used in line 1370 to determine the current x and y deflections. Line 1400 generates the string by concatenating the current values to the string X$(L). The rest of this section increments the character number, L, and continues the input process. These routines are terminated in one of two fashions; if the horizontal coordinate is entered as E, then the current string is set equal to "EOF", and the user may write the font to the disk or return to the main menu (lines 1230-1250); if the routine has been called by the EDIT or MODIFY routines, after the insertion of a single character, control is returned to the calling routine (line 1160). - 7 -