'****************************************************************************
'Copyright 30-9-1998 Luberth Dijkman Bangert 23 1619 GJ Andijk Nederland 
'Qbasic plotter -> more @ http://home.wxs.nl/~luberth/
'Program read a HPGL file and Control's stepper motors connected on parallel port
'this time using 5804 ic's
'Send me a e-mail if u like or use it!?  to luberth@wxs.nl
'Please Send me a copy of your program if you make any changes
'Use @ own risk
'Don't blame me if you blown your dad's brand new computer skyhigh!
'This file is not to be sold or to be part of a commercial product without
'prior written permission from Luberth Dijkman
'All rights reserved.
'****************************************************************************
'                   HPGL file read and display made by James
'****************************************************************************
'Have fun!



SCREEN 12: CLS          'screen12 and clear screen
scale = 5               'The larger the number, the smaller the drawing on SCREEN
OUT (&H378), 0
INPUT " Tell me Path & Name of HPGL plot File  "; f$
IF f$ = "" THEN END
OPEN f$ FOR BINARY AS #1

MotorX(0) = 1: MotorX(1) = 3: MotorX(2) = 2: MotorX(3) = 6: MotorX(4) = 4: MotorX(5) = 12: MotorX(6) = 8: MotorX(7) = 9
MotorY(0) = 16: MotorY(1) = 48: MotorY(2) = 32: MotorY(3) = 96: MotorY(4) = 64: MotorY(5) = 192: MotorY(6) = 128: MotorY(7) = 144
'above lines are output valeus (step coil firing sequence)

xold = 0
yold = 0

DO WHILE NOT EOF(1)
   
	a$ = INPUT$(1, 1)                                   'read file 1 character
	B$ = B$ + a$
   
IF a$ = ";" THEN
	   
	cmd$ = LEFT$(B$, 2)
	IF cmd$ = "PU" THEN mode$ = "M"     'Move
	IF cmd$ = "PD" THEN mode$ = "D"     'Draw
	   
	l = LEN(B$)
	IF l > 3 THEN
		IF cmd$ = "PA" OR cmd$ = "PU" OR cmd$ = "PD" THEN
			comma = INSTR(B$, ",")
	   
			x$ = MID$(B$, 3, comma - 3)
			x = VAL(x$)
			xscreen = VAL(x$) / scale
	   
			y$ = MID$(B$, comma + 1, l - LEN(x$) - 4)
			y = VAL(y$)
			yscreen = VAL(y$) / scale
	   
			IF mode$ = "M" THEN PSET (5 + xscreen, 475 - yscreen), 0
			IF mode$ = "D" THEN LINE -(5 + xscreen, 475 - yscreen), 15
		END IF
	END IF
	B$ = ""
END IF
   
	xnew = x
	ynew = y
   
	
	
	IF xnew < xold THEN xi = xold - xnew ELSE xi = xnew - xold   'this
	IF ynew < yold THEN yi = yold - ynew ELSE yi = ynew - yold   'part
								 'of
	IF xi <= 0 THEN xi = yi                                      'the
	IF yi <= 0 THEN yi = xi                                      'code
								 'is
	IF xi > yi THEN                                              'for
	add2x = 1                                                'lines
	add2y = yi / xi                                          'under
	END IF                                                       'an
								 'angle
	IF yi > xi THEN                                              'other wise
	add2x = xi / yi                                          'the
	add2y = 1                                                'plotter
	END IF                                                       'would
								 'draw
	IF yi = xi THEN                                              'lines
	add2x = 1                                                'other
	add2y = 1                                                'then straight
	END IF                                                       'or 45 degree
								 'lines wrong

REM IF mode$ = "M" THEN OUT (&H378 + 2), 1 XOR 11    'if move then penup activate "strobe" pin1 parallel port
REM IF mode$ = "D" THEN OUT (&H378 + 2), 0 XOR 11    'if pendown then output = off
						 ' the xor 11 is because of inverted state of strobe, init, slct in
						 ' autofeed is not inverted



 IF xnew > xold THEN xdirection = 16 ELSE xdirection = 0  'data 6 -> pin 7
 IF ynew < yold THEN ydirection = 32 ELSE ydirection = 0  'data 7 -> pin 8

 IF xnew = xold THEN xdirection = oldxdirection
 IF ynew = yold THEN ydirection = oldydirection

 oldxdirection = xdirection
 oldydirection = ydirection


acceleratie = 230                       'stepdelay   


stap:
  
  IF INKEY$ = CHR$(27) THEN GOTO theend          'if <escape> is pressed then end program
 
  IF CINT(u) < x THEN u = u + add2x
  IF CINT(u) > x THEN u = u - add2x
  IF CINT(v) < y THEN v = v + add2y
  IF CINT(v) > y THEN v = v - add2y

ValeuX = CINT(u) MOD 8          'used for uln2803 & 5804
ValeuY = CINT(v) MOD 8          'see next lines why for 5804
	 
IF ValeuX <> StoreValeuX THEN stepx = 1 ELSE stepx = 0      'data 1 -> pin 2
IF ValeuY <> StoreValeuY THEN stepy = 2 ELSE stepy = 0      'data 2 -> pin 3

StoreValeuX = ValeuX
StoreValeuY = ValeuY
		
	   OUT (&H378), 0
	   FOR t = 1 TO 1: NEXT t
	   OUT (&H378), (xdirection + ydirection)
	   FOR t = 1 TO 1: NEXT t
	   OUT (&H378), 0
	   FOR t = 1 TO 1: NEXT t
	   OUT (&H378), (xdirection + stepx + ydirection + stepy)
	   FOR t = 1 TO 1: NEXT t
	   OUT (&H378), 0


REM     OUT (&H378), (MotorX(ValeuX)) + (MotorY(ValeuY))       'for uln2803 output
	
	
	
  xi = xi - add2x
  yi = yi - add2y

	IF xi > yi THEN
		IF xi < 20 THEN acceleratie = acceleratie + 2.5
	ELSE IF yi < 20 THEN acceleratie = acceleratie + 2.5
	END IF
	
	 IF acceleratie > 230 THEN acceleratie = 230
	 IF acceleratie < 50 THEN acceleratie = 50
	
	 FOR N = 1 TO acceleratie: NEXT N
	 acceleratie = acceleratie - 1.5
	 
	 IF xnew <> CINT(u) OR ynew <> CINT(v) THEN GOTO stap
	 
xold = x
yold = y

LOOP

theend:

OUT (&H378), 0                          'turn all bits off
OUT (&H378 + 2), 0 XOR 11
CLOSE

END