'PYTA.BAS
SCREEN 13, 15
INPUT "Depth? (1-13) ", Diepte
IF Diepte < 1 THEN RUN
IF Diepte > 13 THEN RUN
CLS
DIM maxel(20), maxelxl(20), maxelxr(20), maxelxm(20)
DIM maxelyl(20), maxelyr(20), maxelym(20)
R = 0: REM r (rij =0)
REM: posities van de wortel:
maxelxl(R) = 272: maxelxm(R) = 368
maxelyl(R) = 430: maxelym(R) = 430
REM
REM: start doorlopen
GOSUB links
FOR i = 1 TO 10000
GOSUB boven
NEXT i
Key$ = INPUT$(1)
END

links: REM doorloop linkertakken en ga 1 naar rechts
curr = R + 1
FOR R = curr TO Diepte
maxel(R) = maxel(R) + 1: tak$ = "links": GOSUB teken
NEXT R
REM: Ga na de linkertakken 1 maal naar rechts.
R = R - 1: GOSUB rechts1
RETURN


rechts1: REM ga naar de rechter tak en doorloop de linker takken to max. diepte
maxel(R) = maxel(R) + 1: tak$ = "rechts": GOSUB teken
IF R <> Diepte THEN GOSUB links
RETURN

boven: REM ga 1 stap naar boven en naar rechts als vorige niet 1/2 van volgende
GOSUB vorige
IF sw1 = 1 AND sw2 = 0 THEN GOSUB rechts1
IF sw1 = 1 AND sw2 = 1 THEN GOSUB boven
RETURN

vorige: REM ga naar vorige rij
sw1 = 0: sw2 = 0: R = R - 1
IF R = 1 THEN a$ = INPUT$(1): END
IF maxel(R + 1) = 2 * maxel(R) THEN sw1 = 1
IF maxel(R) = 2 * maxel(R - 1) THEN sw2 = 1
RETURN

teken: REM bereken de punten, teken de figuur en bewaar linker en rechter element.
IF tak$ = "links" THEN GOSUB haalbasisl
IF tak$ = "rechts" THEN GOSUB haalbasisr
GOSUB bepricht
ON richt GOSUB richt1, richt2, richt3, richt4, richt5, richt6, richt7, richt8
GOSUB slacordop

GOTO spr1
IF tak$ = "rechts" THEN GOSUB printcord
spr1:
GOSUB tekenfig
GOTO spr2
IF tak$ = "rechts" THEN INPUT a$
spr2:
RETURN

haalbasisl: REM Haal posities van basislijn
X1 = maxelxl(R - 1): Y1 = maxelyl(R - 1)
X2 = maxelxm(R - 1): Y2 = maxelym(R - 1)
RETURN

haalbasisr: REM Haal posities van basislijn
X1 = maxelxm(R - 1): Y1 = maxelym(R - 1)
X2 = maxelxr(R - 1): Y2 = maxelyr(R - 1)
RETURN

bepricht: REM Bepaal de richting van de tak.
IF X1 < X2 AND Y1 = Y2 THEN richt = 1
IF X1 < X2 AND Y1 > Y2 THEN richt = 2
IF X1 = X2 AND Y1 > Y2 THEN richt = 3
IF X1 > X2 AND Y1 > Y2 THEN richt = 4
IF X1 > X2 AND Y1 = Y2 THEN richt = 5
IF X1 > X2 AND Y1 < Y2 THEN richt = 6
IF X1 = X2 AND Y1 < Y2 THEN richt = 7
IF X1 < X2 AND Y1 < Y2 THEN richt = 8
RETURN

richt1: REM richting Noord
X3 = X2: Y3 = Y2 - (X2 - X1)
X4 = X1: Y4 = Y3
XM = INT((X3 + X4) / 2): YM = Y3 - INT((X3 - X4) / 2)
RETURN

richt2: REM richting Noord - West
X3 = X1: Y3 = Y2 - (Y1 - Y2)
X4 = X1 - (X2 - X1): Y4 = Y2
XM = X4: YM = Y3
RETURN

richt3: REM richting West
X3 = X2 - (Y1 - Y2): X4 = X3
Y3 = Y2: Y4 = Y1
XM = X4 - INT((Y4 - Y3) / 2): YM = INT((Y4 + Y3) / 2)
RETURN

richt4: REM richting Zuid-West
X3 = X2 - (X1 - X2): X4 = X2
Y3 = Y1: Y4 = Y1 + (Y3 - Y2)
XM = X3: YM = Y4
RETURN

richt5: REM richting Zuid
X3 = X2: X4 = X1
Y3 = Y2 + (X1 - X2): Y4 = Y3
XM = INT((X3 + X4) / 2): YM = Y3 + INT((X4 - X3) / 2)
RETURN

richt6: REM richting Zuid - Oost
X3 = X1: X4 = X1 + (X1 - X2)
Y3 = Y2 + (X1 - X2): Y4 = Y2
XM = X4: YM = Y3
RETURN

richt7: REM richting Oost
X3 = X2 + (Y2 - Y1): Y3 = Y2
X4 = X3: Y4 = Y1
YM = Y4 + INT((Y3 - Y4) / 2): XM = X3 + (YM - Y4)
RETURN

richt8: REM richting Noord-Oost
X3 = X2 + (X2 - X1): Y3 = Y1
X4 = X2: Y4 = Y1 - (Y2 - Y1)
XM = X3: YM = Y4
RETURN

RETURN

slacordop: REM Sla de berekende coordinaten op
maxelxl(R) = X4: maxelyl(R) = Y4
maxelxm(R) = XM: maxelym(R) = YM
maxelxr(R) = X3: maxelyr(R) = Y3
RETURN

tekenfig: REM verbind x1y1,x2y2,x3y3,x4y4 en xmym met elkaar
CLR = R + 40
X1 = X1 / 2.5
X2 = X2 / 2.5
X3 = X3 / 2.5
X4 = X4 / 2.5
Y1 = Y1 / 2.5
Y2 = Y2 / 2.5
Y3 = Y3 / 2.5
Y4 = Y4 / 2.5
XM = XM / 2.5
YM = YM / 2.5
LINE (X1, Y1)-(X2, Y2), CLR
LINE (X2, Y2)-(X3, Y3), CLR
LINE (X3, Y3)-(X4, Y4), CLR
LINE (X4, Y4)-(X1, Y1), CLR
LINE (X3, Y3)-(XM, YM), CLR
LINE (X4, Y4)-(XM, YM), CLR
PAINT ((X4 + X2) / 2, (Y1 + Y3) / 2), CLR
xp = (X4 + X3) / 2
xp = (XM + xp) / 2
yp = (Y4 + Y3) / 2
yp = (YM + yp) / 2
PAINT (xp, yp), CLR
LINE (X1, Y1)-(X2, Y2), 0
LINE (X2, Y2)-(X3, Y3), 0
LINE (X3, Y3)-(X4, Y4), 0
LINE (X4, Y4)-(X1, Y1), 0
LINE (X3, Y3)-(XM, YM), 0
LINE (X4, Y4)-(XM, YM), 0
X1 = X1 * 2.5
X2 = X2 * 2.5
X3 = X3 * 2.5
X4 = X4 * 2.5
Y1 = Y1 * 2.5
Y2 = Y2 * 2.5
Y3 = Y3 * 2.5
Y4 = Y4 * 2.5
XM = XM * 2.5
YM = YM * 2.5

RETURN

printcord: REM print coordinaten
PRINT "rij = "; R; " element = "; maxel(R)
PRINT "x4,y4 = "; maxelxl(R), maxelyl(R)
PRINT "xm,ym = "; maxelxm(R), maxelym(R)
PRINT "x3,y3 = "; maxelxr(R), maxelyr(R)
RETURN