DRAWING PACKAGE

by Nick Harmer and Jonathan Baggaley

When we carried the listing for the Plot Routine by Lawrence Simons (a clever little program to switch pixels on or off) it was predicted (hat we would see some ingenious applications over the coming months. And sure enough this is one the best of the flood of programs all based round this utility.

It's a drawing package that allows you to produce effective and quite accurate graphics on screen. Run the program and the screen goes blank except for a tiny dot in the centre. You can move this dot in any direction using the keys W - Up, Z - down, A - left and S - right, a quite sensible group of keys at the far left of the key board. This will produce a straight line which can be positioned very accurately.

If you want a thicker line press 2 for double thickness and 1 to take you back to the thin line. Make a mistake and you just press E for erase which will remove every pixel you cross until you press I for ink. If you want to move to another part of the screen without leaving a line, press U for brush up and D for brush down starts the flow of 'paint' again. Finally you can add text anywhere you want by simply pressing T for text. When you press return you will return to the normal mode.

As the cursor is normally not shown (except in text mode) it is possible to lose yourself on the screen. At this point chose F and the pixel where the cursor is positioned will flash on and off for a few seconds.

When you are totally delighted with the results you can, of course, get a hard copy of the drawing by pressing [EXTRA] and [PTR] at the same time.

As the program is based on the Plot Routine printed in our August edition any Listings Plus devotees who have already typed this in can save themselves a lot of trouble by merging the lines from 50000 on with new program.

Wie aus dem Artikel zu ersehen ist, wird nach Aufruf des Programms in der Mitte des Bildschirms ein weißer Punkt zu erkennen sein. Dies ist der Ausgangspunkt für die zu erstellende Zeichnung. Folgende Kommandos können dabei verwendet werden:

W: Bewegt Punkt nach oben
Y: Bewegt Punkt nach unten

war im Original Z

A: Bewegt Punkt nach links
S: Bewegt Punkt nach rechts
2: Verdoppelt die Strichstärke
1: Strichstärke auf normal
E: Punk löschen
I: Tinte aktivieren
U: Stift anheben
D: Stift absenken
T: Text eingeben
L: Löschen des Schirms
F: Flackern des Punktes zum Ermitteln des Cursors
Q: Beenden des Programms - neues Kommando

10 GOSUB 50000                                                                         04A0
20 PRINT CHR$(27)+"H";CHR$(27)+"E";CHR$(27)+"f"                                        0BC8
30 X%=360: REM X POS                                                                   0636
40 W%=0: REM BRUSH SIZE                                                                085E
50 Y%=128: REM Y POS                                                                   063D
60 P%=1:REM BRUSH POSITION (DOW/UP)                                                    0E2F
70 F%=1: REM BRUSH STATE (INK/ERASE)                                                   0CE5
80 LET C$=INKEY$                                                                       06E8
90 IF C$="A" OR C$="a" AND X%>0 THEN LET X%=X%-1                                       0DC9
100 IF C$="S" OR C$="s" AND X%<718 THEN LET X%=X%+1                                    0E9D
110 IF C$="W" OR C$="w" AND Y%<256 THEN LET Y%=Y%+1                                    0EC1
120 IF C$="Z" OR C$="z" AND Y%<8 THEN LET Y%=Y%-1                                      0F92
130 IF C$="I" OR C$="i" THEN LET F%=1: REM INK ON                                      100D
140 IF C$="E" OR C$="e" THEN LET F%=0: REM INK ERASE                                   11BD
150 IF C$="C" OR C$="c" THEN PRINT CHR$(27)+"H";CHR$(27)+"E"                           1089
160 IF C$="D" OR C$="d" THEN LET P%=1                                                  0B7D
170 IF C$="U" OR C$="u" THEN LET P%=0                                                  0BF4
180 IF C$="T" OR C$="t" THEN GOSUB 260                                                 0C53
190 IF C$="2" THEN W%=1                                                                0681

200 IF C$="1" THEN W%=0                                                                0668
210 IF C$="F" OR C$="f" THEN 360                                                       08E4
220 IF P%=0 THEN GOTO 80                                                               0815
230 CALL PLOT (X%,Y%,F%)                                                               07AC
240 IF W%=1 THEN 290                                                                   06A7
250 GOTO 80                                                                            036C
260 A%=X%/8:B%=INT((256-Y%)/8):PRINT CHR$(27)+"e";                                     0D57
270 PRINT CHR$(27)+"Y"+CHR$(32+B%)+CHR$(32+A%);:INPUT "",T$:PRINT CHR$(27)+"f";        16AA
280 RETURN                                                                             03C2
290 A%=X%-1:B%=X%+1:C%=Y%-1:D%=Y%+1                                                    08BC
300 IF X%>0 THEN CALL PLOT (A%,Y%,F%)                                                  0C3D
310 IF X%<718 THEN CALL PLOT (B%,Y%,F%)                                                0BF4
320 IF Y%<255 THEN CALL PLOT (X%,D%,F%)                                                0C4A
330 IF Y%>0 THEN CALL PLOT (X%,C%,F%)                                                  0C09
340 GOTO 80                                                                            036B
350 G%=F%                                                                              01DD
360 FOR Z=1 TO 25                                                                      059A
370 G%=(G%+1) AND 1                                                                    03B3

380 CALL PLOT (X%,Y%,G%)                                                               07BC
390 FOR Y=1 TO 50:NEXT Y                                                               08A4
400 NEXT Z                                                                             0367
410 GOTO 80                                                                            0366
50000 MEMORY &HBFFF:PLOT=&HC000:A=PLOT:E=0                                             0F5F
50010 RESTORE 50120                                                                    05C2
50020 FOR F=0 TO 14                                                                    0537
50030 S=0                                                                              024B
50040 FOR G=0 TO 7                                                                     052C
50050 READ X$:X=VAL("&H"+X$)                                                           0789
b3C50060 S=S+X:POKE A,X:A=A+1:NEXT                                                     0B3C
50070 READ X$:IF S<>VAL("&H"+X$) THEN E=E+1:PRINT "ERROR IN LINE ";10*(F+5012)         19E8
50080 NEXT                                                                             02D2
50090 IF E=0 THEN RETURN                                                               0922
50100 PRINT E; "ERROR";:IF E=1 THEN PRINT ELSE PRINT "S"                               12FD
50110 STOP                                                                             02C6
50120 DATA 0A,32,7C,C0,4E,23,46,21,250                                                 0887
50130 DATA CF,02,A7,ED,42,D8,ED,43,4AF                                                 09B1

50140 DATA 78,C0,EB,5E,23,56,7A,A7,41B                                                 0994
50150 DATA C0,93,3D,5F,ED,53,7A,C0,469                                                 094F
50160 DATA F3,ED,73,7D,C0,31,9D,C0,51E                                                 095C
50170 DATA 01,36,C0,CD,5A,FC,E9,00,403                                                 0953
50180 DATA ED,7B,7D,C0,FB,C9,2A,7A,50D                                                 09F3
50190 DATA C0,29,11,00,B6,19,5E,23,24A                                                 0823
50200 DATA 56,7B,E6,F8,CB,27,CB,12,47E                                                 08FC
50210 DATA 47,7B,E6,07,B0,5F,2A,78,360                                                 08CD
50220 DATA C0,45,7D,E6,F8,6F,EB,19,4D3                                                 0955
50230 DATA 78,E6,07,3C,47,AF,37,1F,2ED                                                 09C0
50240 DATA 10,FD,47,3A,7C,C0,A7,20,391                                                 08E7
50250 DATA 05,78,2F,A6,77,C9,3D,78,347                                                 0926
50260 DATA 20,03,B6,77,C9,AE,77,C9,407                                                 091B

[BASIC-Original-Listing], [BASIC-Listing] und [Assembler-Listing]