williams-et-al-1983-apple-ii-computer-graphics

CHAPTER 6-TEXT AND LOW-RES 4960 REM70 IF PF THEN PLOT X ,Y:PF = 080 IF C$ = "J" AND X > 0 THEN X X-1:GOTO 19090 IF C$ = "I" AND Y > 0 THEN Y Y-1:GOTO 190100 IF C$ = "K" AND X < 39 THEN X X + 1:GOTO 190110 IF C$ = "M" AND Y < 39 THEN Y Y + 1:GOTO 190120 IF C$ = "U" AND X > 0 AND Y > 0 THENX = X-l :Y = Y-1: GOTO 190130 IF C$ = "0" AND X < 39 AND Y > 0 THENX = X + l :Y = Y-1: GOTO 190140 IF C$ = " , " AND X < 39 AND Y < 39 THENX = X + 1: Y = Y + 1: GOTO 190150 IF C$ = "N" AND X > 0 AND Y < 39 THENX = X-l :Y = Y + 1: GOTO 190160 IF C$ "P" THEN PF = 1: GOTO 190170 IF C$ = "Q" THEN GOTO 280180 IF C$ = "C" THEN GOSUB 230190 GOTO 40 : REM BACK TO TOP OF LOOP200 REM210 REM SET COLOR220 REM230 VTAB (24) : INPUT "NUMBER FOR NEWCOLOR:?";CN$240 CN = VAL (CN$ ) : IF CN < 0 OR CN > 15THEN PRINT CHR$ (7) : GOTO 230250 PRINT : PRINT : PRINT : PRINT"COLOR = "; CN260 COLOR = CN270 RETURN28i;l REM290 REM300 PRINT "QUIT? (Y/N) "; : GET R$310 IF R$ < > "Y" GOTO 40320 ENDListing 6-4. Low-Res editor.This editor is not elaborate, but it does give you the fu nctions necessaryto plot and edit pictures on the Low-Res screen, and it is easily modified tosuit your individual requirements.When you run the editor, you will fi rst be asked to enter the number ofthe color to be plotted. The computer will ask:NUMBER FOR NEW COLOR :?