Star Micronics SG-10, SG-15 user manual 140 ’

and SG-IO/15 plotting the output, you can come up with some terrific business graphs, charts, and mathematical function plots.

The best way to do this is to set up an array in memory. This is your “graph paper.” The first thing to do is to determine how big you want your output to be; this will determine the size of your array. (If you have grandiose plans to fill an entire page with plotter output, you better have lots of memory in your computer. With 60 dots per inch horizontally and 72 dots per inch vertically, it takes at least 540 bytes of memory for each square inch of plotted area. That doesn’t sound so bad-but an area 8 inches square requires over 32K!)

Your array should be two-dimensional (just like graph paper) where one dimension will be the number of columns of dots and the other dimension is the number of printing lines (remember that you can have up to eight rows of dots per printed line).

Here’s a program that will use calculated-shape graphics to plot a circle. As you’ll see, by changing a few lines it can be used to plot virtually any shape.

10' General purpose for plotting program

20	’
30	'Set program constants.
40	MAXCOL% = 75	: MAXROW% = 14
50 DIM BIT%(MAXCOL%, MAXROW%)
60	MASK%(l) = 64	: MASK%(4) = 8
70 MASK%(2) = 32		: MASK%(5) = 4
80	MASK%(3) = 16	: MASK%(G) = 2
90	LX = 20	: LY = 20
100 LXFAC = 72/LX		: LYFAC = 87/LY
110 '

120'Plot curve.

130GOSUB 600

140’

150'Send bit image map to printer.

169)LPRINT CHR$(27) "A" CHRS(6)

170FOR ROW% = 0 TO MAXROW%

180A$ = ""

190LPRINT CHR$(27) "K" CHR$(MAXCOL%) CHR$(fl);

200FOR COL% = 1 TO MAXCOL%

214)A$ = A$ + CHR$(BIT%(COL%,ROW%>> 220 NEXT COL%

230 LPRINT A$ " "

240 NEXT ROW%

250 LPRINT CHR$(27) "2"

260 END

111