C
C==========================================================================
C
C	Tektronix 4010 graphics driver
C
C	8.0" x 6.0"  (1024 x 780)
C
C==========================================================================
C
	JDEV = JDEV - 1
	IF (JDEV .NE. 0) GOTO 1999
C
	IF ((IMODE .LT. -5) .OR. (IMODE .GT. 6)) RETURN
	GOTO (1000,1005,1010,1020,1030,1040,1050,1060,1070,1090,1095,1100),
	1						IMODE+6
C
C	mode -5: we exist
C
1000	X = 1.0
	GOTO 90
C
C	mode -4: initialize
C
1005	CALL GTATT(LUNGRP)		! attach the terminal, set up the loon
	GOTO 90
C
C	mode -3: return screen size
C
1010	X = 8.0
	Y = 6.0
	GOTO 90
C
C	mode -2: alpha cursor position
C
1020	CALL GTTEKI(IX,IY,I,2)		! request alpha cursor position
	X = IX / 127.875
	Y = IY / 130.000
	GOTO 90
C
C	mode -1: graphics cursor position
C
1030	CALL GTTEKI(IX,IY,I,1)		! request graphics cursor position
	X = IX / 127.875
	Y = IY / 130.000
	XT = XTLAST			! get where we were ...
	YT = YTLAST
	GOTO 1050			! and put us back there
C
C	mode 0: initialize and clear screen
C
1040	CALL GT(ESCAPE)			! clear screen: <esc> <formfeed>
	CALL GT("14)
	CALL GTF			! flush the buffer (do it)
	GOTO 90
C
C	mode 1: unwritten vector
C
1050	CALL GT("35)			! <GS> invokes graphics; dark vect 1st
	GOTO 1080
C
C	mode 2: written vector
C
1060	GOTO 1080			! must assume in graf mode.  do it.
C
C	mode 3: point plot
C
1070	CALL GT("34)			! <FS> invokes point plot mode
C
C	modes 1,2,3: send out the X,Y coordinates
C
1080	IX = MIN1(1023.,AMAX1(0.,127.875*XT+0.5))
	IY = MIN1( 779.,AMAX1(0.,130.000*YT+0.5))
	CALL GTTEK(IX,IY)
	GOTO 90
C
C	mode 4: finish the plot
C
1090	CALL GT("35)			! dark vector
	CALL GTTEK(0,779)		!  to the top left corner
	CALL GT("15)			! enter alpha mode
	CALL GTF			! flush the buffer
	CALL GTATT(-LUNGRP)		! deattach the terminal
	CALL CLOSE(LUNGRP)
	GOTO 90
C
C	mode 5: set nibs and linepattern
C
1095	NIBS = X
	LINPAT = Y
	GOTO 90
C
C	mode 6: identify ourself
C
1100	WRITE (LUN,1110)
1110	FORMAT('+	Tektronix 4010 graphics terminal')
	GOTO 90
C
C	and link to the next device
C
1999	CONTINUE