270 '
280'Subroutine to draw a line from Xl,Yl to X2,Y2.
290’
300 | XL = X2 - Xl | : YL = Y2 - Yl |
310 | Nx = ABS(XL"LXFAC) : NY = ABS(YL$cLYFAC) | |
320 | IF NX < NY THEN NX = NY | |
330 | NS% = INT(NX+l) |
|
340 | DX = XL/NS% | : DY = YL/NS% |
354)FOR 1% = 1 TO NS% |
| |
364)xl = Xl + DX | : Yl = Yl + DY | |
370 | GOSUB 400 |
|
384)NEXT 1% |
| |
390 | RETURN |
|
400’
410'Subroutine to plot a point at Xl,Yl.
424)’
430 XX = Xl * LXFAC : YY = Yl ;:LYFAC- 440 COL% = INT(XX) + 1
454)ROW% = INT(YY/b)
460 XIT% = IST(YY -
470BIT?(COL%,ROW%) = BIT?'(COLP,ROWZ)OR ?lASK%(XITZ)
480RETURN
600’
61g ’ Subroutine to plot a circle.
620’
634)KAD = 9
644)Xl = 19: Yl = 10
650 FOR ANG? = 0 TO 360 STEP 10
660 RANG = ANGb"6.28/360
670 x2 =
699)NEXT ANG%
700 RETURN
If you are using with the IBM mode, change the following lines to the program given above.
160 LPRINT CHR$(27) "A" CHR$(6) CHR$(27) "2" 250 LPRINT CHR$(27) "A" CHR$(12) CHR$(27) "2"
H How the program works
In the program above, we’ve created an array called BIT%, which is dimensioned in line 50. You’ll note that instead of using numeric constants to dimension the array, we used the variables MAXCOL% and MAXROW%. This way, if your computer has enough memory and you want to plot a larger image. all
-
-
-
-
-
112
