C
C===========================================================================
C
C	Graphics driver for DEC GIGI terminal
C
C	8.35" x 6.45"		(768 x 480)
C
C============================================================================
C
	JDEV = JDEV - 1
	IF (JDEV .NE. 0) GOTO 5999
C
5000	IF ((IMODE .LT. -5) .OR. (IMODE .GT. 6)) RETURN
	GOTO (5001,5005,5010,90,90,5020,5030,5040,5030,5070,5080,5200),
	1						IMODE+6
C
C	mode -5: tell them we exist
C
5001	X = 1.0
	GOTO 90
C
C	mode -4: initialize
C
5005	CALL GTATT(LUNGRP)		! attach the device
	CALL GT(ESCAPE)			! make sure we're in ANSI mode
	CALL GT('<')
	CALL GT(ESCAPE)			! set several graphics defaults
	CALL GT('Pp;S(I0N0A)W(VI4A0S0M1N0P1)P[0,0];')
	CALL GTF			! flush the buffer
	NIBS = 1
	LINPAT = -1
	GOTO 90
C
C	mode -3: return screen size
C
5010	X = 8.35
	Y = 6.45
	GOTO 90
C
C	mode 0: clear screen
C
5020	CALL GT('S(E);')		! clear the screen
	CALL GTF
	GOTO 90
C
C	mode 1,3: unwritten vector, point plot
C
5030	CALL GT('P[')
	GOTO 5050
C
C	mode 2: written vector
C
5040	CALL GT('V[')
C
C	modes 1,2,3: ship out the X,Y coordinates
C
5050	IX = MIN1(767.,AMAX1(0.,91.9760*XT+0.5))
	IY = 479 - MIN1(479.,AMAX1(0.,74.4186*YT+0.5))
	ENCODE(7,5060,BUFFER) IX, IY
5060	FORMAT (I3,',',I3)
	CALL GT(BUFFER,7)
	CALL GT(']')
	IF (IMODE .EQ. 3) CALL GT('V[];') ! point plot
	GOTO 90
C
C	mode 4: finish the plot
C
5070	CALL GT('P[0,0]')		! get to the top left corner
	CALL GT(ESCAPE)			! <esc>
	CALL GT('\')			! return to alpha mode
	CALL GT(ESCAPE)			! make sure we're home
	CALL GT('[H')
	CALL GTF			! flush the buffer
	CALL GTATT(-LUNGRP)		! deattach the device
	CALL CLOSE(LUNGRP)
	GOTO 90
C
C	mode 5: nibs (X; intensity) and line pattern (Y; as is)
C
5080	IY = IFIX(Y) .AND. "377		! 8 bits only for GIGI lines ...
	IF (IY .LE. 0) IY = "377
	IF (LINPAT .EQ. IY) GOTO 5110
	LINPAT = IY
	IF (LINPAT .NE. "377) GOTO 5085	! check for -1: solid line
	CALL GT(';W(P1);')		! set lines of all ones
	GOTO 5110
5085	CALL GT(';W(P')			! GIGI 'writing pattern'
C
	DO 5100 I=7,0,-1
	IX = 2**I
	IF (IX .GT. LINPAT) GOTO 5090
	CALL GT('1')			! set this bit on
	LINPAT = LINPAT - IX
	GOTO 5100
5090	CALL GT('0')			! set this bit off
5100	CONTINUE
	CALL GT(');')
	LINPAT = IY			! restore the line pattern
C	intensity
5110	IX = X
	IF (IX .EQ. NIBS) GOTO 5120
	NIBS = IX
	IF (NIBS .LE. 1) CALL GT(';W(I4);') ! half intensity for NIBS = 1
	IF (NIBS .GT. 1) CALL GT(';W(I7);') ! full intensity for NIBS > 1
5120	GOTO 90
C
C	mode 6: identify ourself
C
5200	WRITE (LUN,5210)
5210	FORMAT('+	DEC GIGI graphics terminal')
	GOTO 90
C
C	continue on to the next device
C
 5999	CONTINUE