This program is typed in from the DECUS DTR newsletter vol 4 no 9.
It consists of several files whose intent is to provide a SIXEL
command. This command will convert ReGIS files to SIXEL files for
dumping to printers like LN03.
        DTR graphics can be plotted onto ReGIS files with commands
like

DTR>READY YACHTS
DTR>PLOT X_Y LOA,PRICE OF YACHTS ON YACHTS.SLO
DTR>EXIT

The YACHTS.SLO file is a ReGIS file. While DECSlide will do the conversion,
it's expensive.

SIXEL can run interactively, using output logical DISPLAY$DEVICE which
defaults to TT:. It must be able to allocate DISPLAY$DEVICE.


[File SIXEL.CLD]

        DEFINE VERB SIXEL
        IMAGE "APPLICATIONS$DISK:CONVERT_TO_SIXEL"
        PARAMETER P1
                LABEL = REGIS_FILE
                VALUE (TYPE = $FILE, REQUIRED)
                PROMPT = "ReGIS Input File"
        PARAMETER P2
                LABEL = SIXEL_FILE
                VALUE (DEFAULT = "SIXEL.SLS")
        QUALIFIER LOCAL
                NONNEGATABLE
                PLACEMENT = GLOBAL
        QUALIFIER RESET
                NONNEGATABLE
                PLACEMENT = GLOBAL
        QUALIFIER GRAPH_TYPE
                VALUE (TYPE=GRAPH_KEYWORDS)
                NONNEGATABLE
                PLACEMENT = GLOBAL
        DISALLOW SIXEL_FILE AND LOCAL
        DEFINE TYPE GRAPH_KEYWORDS
                KEYWORD COMPRESSED
                KEYWORD EXPANDED
                KEYWORD ROTATED
[END OF SIXEL.CLD]

        To use to create a SIXEL file from a ReGIS file you'd give
a command like

$SIXEL YACHTS.SLO YACHTS.SLS
which uses the default VT240 ReGIS setup.

To make a rotated graph use the command
$SIXEL/GRAPH_TYPE=ROTATED YACHTS.SLO YACHTS.SLS

GRAPH_TYPE=EXPANDED or GRAPH_TYPE=COMPRESSED
can be used by instructing the VT240 to do expanded or compressed
graphs.

The following is an example of use:

$! Make sixel file for print...
$!1st, create the ReGIS file.
$DTR
        Ready YACHTS
        Plot X_Y LOA,price of YACHTS on YACHTS.SLO
        Exit
$!
$ DEFINE DISPLAY$DEVICE _TTA6:          ! TTA6: IS A VT240
$ SIXEL/GRAPH=EXPANDED YACHTS.SLO MY_GRAPH.SIX
$ PRINT MY_GRAPH.SIX

Note that a real VT240 is needed since the ReGIS to SIXEL conversion
is done in hardware on that.

        Note that the command

$SET HOST 0/log=logfile

could be used to capture characters sent to a VT240 in logfile if a
ReGIS plot package that has no file output provisions is used.

[file SIXEL.FOR]
        PROGRAM CONVERT_TO_SIXEL
C       VERSION 1.0
C
C       Functional description:
C
C	This program will convert a ReGIS graphics file (such as one produced
C by DTR) and produce a SIXEL graphics file suitable for printing on an
C appropriate printer (LA50, LA100, LN03, etc.). It was written  by
C Donald E. Stern mainly to get around the need for DECSlide to create
c Sixel files because DECslide isn't cheap, and DECSlide can't be used from batch.
c
c Since the sixel conversion is a hardware function of a graphics
c terminal, the program requires use of a ReGIS terminal. This device
c is defined by the logical DISPLAY$DEVICE. For an interactive terminal
c one must make a definition like
c  DEFINE DISPLAY$DEVICE TT:
C
c If there is no translation for DISPLAY$DEVICE, this definition will
c be assumed. In addition the device should be set to REGIS and the
c program will abort if this is not done.
c
c The specified ReGis file is opened and sent to display$device and
c then the required sequences which set graphics to host are sent,
c followed by commands to enter REGIS and initiate hardcopy output.
c
c The appropriate terminal characteristics are set and successive QIOs
c are issued to read the SIXEL data which returns a byte at a time.
c The end is signalled by receipt of the byte after the 3rd
c <esc> character is detected. The sixel data is collected in a 255
c character buffer which is written to disk when full. Thus the
c sixel file can be edited with a standard text editor if desired.
c
c Input comes from the commandline interpreter, specifically
c cli$get_value and cli$present. The SIXEL.CLD file [above] contains
c the necessary information to define the SIXEL command.
c
c Switches /graph_type, /reset, and /local are optional. If /graph_type
c is EXPANDED the sixel output is about 12 by 8 inches, ROTATED gives about
c 8 x 12 inches, and rotated 90 degrees (fits on normal 8.5 by 11 paper).
c COMPRESSED gives a plot about 6 by 3 inches.
c
c If /local is set, sixel output goes to a printer attached directly
c to display$device and no sixel-file-sopec is allowed.
c
c If /reset is specified, display$device will be set to COMPRESSED mode
c before exiting; otherwise it's left in the mode set by GRAPH_TYPE
c options.
c
c Created 1986 Warner-Lambert Co.
c	Consumer Health Products Grp.
c	Milford, Conn. 06460
c
c Author: Donald E. Stern, Jr. 2/4/86
c
c Execution environment: VMS V4.2 or later
c
c Functions called
c
c	GET_TERMINAL_CHARACTERISTICS	- Internally developed routine to
c						get terminal characs.
c
c	SET_TERMINAL_CHARACTERISTICS	- Internally developed routine to
c						set terminal characs.
c	SYS$QIOW			- SYNCH. QIO
C 	SYS$ASSIGN			- Assign chnl # to device
c	cli$present			- RTL CLI arg detect
c	cli$get_value			- RTL CLI arg fetch
c 	lib$sys_trnlog			- translate logical name
c	li$set_logical			- create logical name
c	lib$getdvi			- get device info
c
c sys$qio structures
	INTEGER*2 INPUT_CHAN	! I/O CHANNEL
	INTEGER CODE,	! TYPE OF I/O OP
     1  INPUT_BUFFER_SIZE,  ! INPUT BUF SIZE, BYTES
     2  INPUT_SIZE  ! SIZE OF INPUT AS READ
	PARAMETER (INPUT_BUFFER_SIZE=1)
C
C TERM CHARAC BUFFER

	BYTE CLASS,
     1  TYPE
	INTEGER*2 WIDTH
	INTEGER*4 BASIC,EXTENDED
	INTEGER*4 OLD_BASIC,OLD_EXTENDED ! OLD TERM CHARACS
C
C I/O OP DEFS
C
	INCLUDE '($IODEF)'
C
C TERM I/O OP MODIFIERS
C
	INCLUDE '($TTDEF)'
	INCLUDE '($TT2DEF)'
C
C SYS SERVICE DEFS
C
	INCLUDE '($SSDEF)'
C
C DEVICE INFO DEFS
C
C
	INCLUDE '($DVIDEF)'
	INCLUDE '($DCDEF)'
C
C QIO STAT BLK
	STRUCTURE /IOSTAT_BLOCK/
	INTEGER*2 IOSTAT,  ! RETURN STATUS
     1  TERM_OFFSET,       ! LOCATION OF LINE TERMINATOR
     2  TERMINATOR,        ! VALUE OF TERMINATOR
     3  TERM_SIZE          ! SIZE OF TERMINATOR
	END STRUCTURE
	RECORD /IOSTAT_BLOCK/ IOSB
C
C SUBPROGRAMS
C
	INTEGER*4 SYS$ASSIGN, SYS$QIOW, CLI$PRESENT,
     1  CLI$GET_VALUE,LIB$SYS_TRNLOG,LIB$SET_LOGICAL,
     2  LIB$GETDVI

	INTEGER*4 STATUS   ! RETURN STATUS
	INTEGER*4 DEVICE_CLASS  ! CLASS RETURNED BY GETDVI
C
	BYTE ENTER_REGIS(4) ! ESC SEQ TO ENTER REGIS MODE
	BYTE EXIT_REGIS(2)  ! EXIT REGIS
	BYTE LOCK_KEYBOARD(4) ! LOCK KEYBOARD
	BYTE UNLOCK_KEYBOARD(4)
	BYTE GRAPHICS_TO_HOST(5)
	BYTE GRAPHICS_TO_PRINTER(5)
	BYTE EXPANDED_PRINT(6)
	BYTE ROTATED_PRINT(6)
	BYTE COMPRESSED_PRINT(6)

	INTEGER*2 NR,   ! # CHARS IN REGIS_FILE
     1  NS,             ! # CHARS IN SIXEL-FILE
     2  NG,             ! # CHARS IN QUALIFIER
     3  NT              ! # CHARS IN TRANSLATION

	CHARACTER*2 EXIT_GRAPHICS ! SAME AS EXIT_REGIS
	CHARACTER*10 GRAPH_TYPE ! CMD LINE QUALIFIER
	CHARACTER*13 MAKE_HARDCOPY  ! REGIS INST TO MAKE GRAPHICS HARDCOPY
	CHARACTER*255 REGIS_FILE
	CHARACTER*255 SIXEL_FILE
	CHARACTER*255 TRANSLATION ! LOG NAME TRANSLATION
	CHARACTER*256 BUFF ! BUFFER FOR REGIS & SIXEL FILES
C
	LOGICAL QUIT
	EQUIVALENCE (EXIT_REGIS(1),EXIT_GRAPHICS)

	DATA ENTER_REGIS /27,80,49,112/ ! $Plp
	data exit_regis /27,92/ ! $\
	data lock_keyboard /27,91,50,104/ ! $[2h
	data unlock_keyboard /27,91,50,108/ ! $[2l
	data graphics_to_host /27,91,63,50,105/ ! $[?2i
	data graphics_to_printer /27,91,63,48,105/ ! $[?0i
	data expanded_print /27,91,63,52,51,104/ ! $[?43h
	data rotated_print /27,91,63,52,55,104/ ! $[?47h
	data compressed_print /27,91,63,52,51,108/ ! $[43l
	data make_hardcopy /'S(H(P[50,0]))'/
C
C SEE IF THERE'S A TRANSLATION OF DISPLAY$DEVICE AND IF NOT ASSIGN
C TT: TO IT.

	STATUS=LIB$SYS_TRNLOG('DISPLAY$DEVICE',NT,TRANSLATION,,,)
	IF (STATUS .EQ. SS$_NOTRAN)
     1   STATUS= LIB$SET_LOGICAL('DISPLAY$DEVICE','TT:',,,)
	IF (.NOT. STATUS)
     1  STOP 'Error translating or defining DISPLAY$DEVICE'
C
C ENSURE DISPLAYDEVICE IS A TERMINAL
	CODE=DVI$_DEVCLASS
	STATUS=LIB$GETDVI(CODE,,'DISPLAY$DEVICE',DEVICE_CLASS,,)
	IF (STATUS.EQ.SS$_NOSUCHDEV)
     1  STOP 'Error - DISPLAY$DEVICE is unknown'
	If (.not.status)STOP 'Error getting device information'
	IF (DEVICE_CLASS.NE.DC$_TERM)
     1  STOP 'ERROR- DISPLAY$DEVICE is not a terminal.'
C ASSIGN CHANNEL TO DISPLAY$DEVICE
C GET #

	STATUS=SYS$ASSIGN('DISPLAY$DEVICE',INPUT_CHAN,,)
C STOP ON ERRORS
	IF (.NOT.STATUS) 
     1  STOP 'Error assigning channel to DISPLAY$DEVICE'
C
C GET AND SAVE TERMINAL CHARACTERISTICS
	CALL GET_TERMINAL_CHARACTERISTICS(INPUT_CHAN,CLASS,
     1 TYPE,WIDTH,BASIC,EXTENDED)
	OLD_BASIC=BASIC
	OLD_EXTENDED=EXTENDED
C CHECK REGIS TERM
	IF((EXTENDED.AND.TT2$M_REGIS).EQ.0)
     1  STOP 'DISPLAY$DEVICE must be set to support ReGIS'
C
C USE CLI TO GET INPUTS
	STATUS=CLI$GET_VALUE('REGIS_FILE',REGIS_FILE,NR)
	IF(.NOT.STATUS) CALL LIB$SIGNAL(%VAL(STATUS))
	IF(CLI$PRESENT('SIXEL_FILE'))
     1  STATUS=CLI$GET_VALUE('SIXEL_FILE',SIXEL_FILE,NS)
	IF(.NOT.STATUS) CALL LIB$SIGNAL(%VAL(STATUS))
	IF(CLI$PRESENT('GRAPH_TYPE'))
     1  STATUS=CLI$GET_VALUE('GRAPH_TYPE',GRAPH_TYPE,NG)
	IF(.NOT.STATUS) CALL LIB$SIGNAL(%VAL(STATUS))
C OPEN INPUT FILE

	OPEN(UNIT=1,NAME=REGIS_FILE(1:NR),
     1  ACCESS='SEQUENTIAL',STATUS='OLD',
     2  READONLY,FORM='FORMATTED',RECORDTYPE='VARIABLE',
     3  CARRIAGECONTROL='LIST',ERR=1100)
C ASSOC LUN 7 WITH DISPLAY$DEVICE FOR LARGE RECORDS

	OPEN(UNIT=7,NAME='DISPLAY$DEVICE',RECL=1024,
     1  STATUS='OLD',ERR=1200)
C
C LOCK KEYBOARD
	WRITE(7,18)LOCK_KEYBOARD
18	FORMAT('$',4A1)
C
C READ REGIS CODE AND DISPPAY TO LUN 7
C
20	READ(1,25,END=100,ERR=1300)NC,BUFF(1:NC)
25	FORMAT(Q,A)
	WRITE(7,27)BUFF(1:NC)
27	FORMAT('+',A)
	GOTO 20
C LOOPS TILL EOF
100	CLOSE(UNIT=1)
C
C OPEN NEW FILE FOR SIXEL OUTPUT
	OPEN(UNIT=1,NAME=SIXEL_FILE(1:NS),
     1  ACCESS='SEQUENTIAL',STATUS='NEW',
     2  FORM='UNFORMATTED',RECORDTYPE='VARIABLE',
     3  CARRIAGECONTROL='LIST',ERR=1400)
C
C SET REQUIRED TERMINAL CHARACTERISTICS
C
	BASIC=BASIC.OR.
     1  TT$M_HOSTSYNC .OR. TT$M_NOBRDCST .OR. TT$M_NOECHO .OR.
     2  TT$M_TTSYNC

	BASIC=IBCLR(BASIC,TT$V_WRAP)
	BASIC=IBCLR(BASIC,TT$V_EIGHTBIT) ! USE 7 BIT CODES
	EXTENDED=EXTENDED.OR.TT2$M_PASTHRU .OR. TT2$M_XON
	CALL SET_TERMINAL_CHARACTERISTICS(INPUT_CHAN,CLASS,
     1  TYPE,WIDTH,BASIC,EXTENDED)
C
C SET UP TERMINAL TO PRINT GRAPHICS
C
	IF(GRAPH_TYPE(1:NG) .EQ. 'EXPANDED') THEN
		WRITE(7,102)EXPANDED_PRINT
	MAKE_HARDCOPY(7:7)='0'
	ENDIF
	IF(GRAPH_TYPE(1:NG) .EQ. 'ROTATED') THEN
		WRITE(7,102)ROTATED_PRINT
	MAKE_HARDCOPY(7:7)='0'
	ENDIF
	IF(GRAPH_TYPE(1:NG).EQ.
     1  'COMPRESSED') WRITE(7,102)COMPRESSED_PRINT
101	FORMAT('+',2A1,5A1,4A1,A13,$)
102	FORMAT('+',6A1,$)
103	FORMAT('+',2A1,4A1,A13,$)
104	FORMAT('+',2A1,4A1,$)

	IF(CLI$PRESENT('LOCAL'))THEN ! HARDCOPY TO LOCAL PRINTER
		WRITE(7,103)EXIT_REGIS,ENTER_REGIS,MAKE_HARDCOPY
		WRITE(7,104)EXIT_REGIS,UNLOCK_KEYBOARD
	ELSE
		WRITE(7,101)EXIT_REGIS,GRAPHICS_TO_HOST,
     1  ENTER_REGIS,MAKE_HARDCOPY
		N = 1 ! POSITION IN BUFF
		NESC = 0 ! COUNTER OF ESCS
		QUIT = .FALSE.
		CODE = IO$_READVBLK ! I/O CODE = READ VIRTUAL
200	STATUS=SYS$QIOW(,
     1  %VAL(INPUT_CHAN),  ! DISPLAY$DEVICE
     2  %VAL(CODE),        ! READ VIRT BLK
     3  IOSB,,,            ! I/O STATUS
     4  %REF(BUFF(N:N)),   ! INPUT BUFFER
     5  %VAL(INPUT_BUFFER_SIZE),,,,)  ! BUFFER SIZE 

	IF(.NOT.STATUS)GOTO 1000
	IF(.NOT.IOSB.IOSTAT) GOTO 1000
	IF(QUIT) GOTO 250

C CHECK FOR ESC AND COUNT
	IF(BUFF(N:N) .EQ. CHAR(27))NESC=NESC+1
	IF(NESC.EQ.3) QUIT=.TRUE.
C FLAG QUIT FOR CHAR AFTER 3RD ESCAPE
C
C WRITE BUFFER IF FULL
	IF(N.EQ.255)THEN
		WRITE(1)BUFF(1:255)
		N=0
	ENDIF
	N = N+1
	GOTO 200  ! LOOP FOR WHOLE IMAGE
250	WRITE(1)BUFF(1:N)
	CLOSE(UNIT=1)
	WRITE(7,252)EXIT_GRAPHICS,UNLOCK_KEYBOARD,
     1  GRAPHICS_TO_PRINTER
252	FORMAT('+',A2,4A1,5A1)
	ENDIF
C
C RESET TERMINAL CHARACTERISTICS
	CALL SET_TERMINAL_CHARACTERISTICS(INPUT_CHAN,CLASS,
     1  TYPE,WIDTH,OLD_BASIC,OLD_EXTENDED)
	IF(CLI$PRESENT('RESET'))WRITE(7,102)COMPRESSED_PRINT
	STOP 'Conversion completed'
c The following lines process errors
1000	CONTINUE
	WRITE(7,252)EXIT_GRAPHICS,UNLOCK_KEYBOARD,
     1  GRAPHICS_TO_PRINTER
	CALL SET_TERMINAL_CHARACTERISTICS(INPUT_CHAN,CLASS,
     1  TYPE,WIDTH,OLD_BASIC,OLD_EXTENDED)
	STOP 'ERROR READING SIXEL'
1100	STOP 'ERROR OPENING REGIS FILE'
1200	STOP 'ERROR READING LUN 7'
1300	STOP 'ERROR READING REGIS DATA'
1400	STOP 'ERROR OPENING SIXEL FILE'
	END
        SUBROUTINE GET_TERMINAL_CHARACTERISTICS (CHANNEL,
     1  CLASS, TYPE, WIDTH, BASIC,EXTENDED)
C
C GETS TERMINAL CHARS IN INPUTS BASIC, EXTENDED.
        INTEGER*2 CHANNEL
        BYTE CLASS
        BYTE TYPE
        INTEGER*2 WIDTH
        INTEGER*4 BASIC,EXTENDED
C
C I/O OP DEFS
        INCLUDE '($IODEF)'
C QIO STAT BLK
        STRUCTURE /IOSTAT_BLOCK/
        INTEGER*2 IOSTAT
        BYTE TRANSMIT,RECEIVE,CRFILL,LFFILL,PARITY,ZERO
        END STRUCTURE
        RECORD /IOSTAT_BLOCK/ IOSB
C
C CHARAC. BUFFER
        STRUCTURE /CHARACTERISTICS/
        BYTE CLASS,TYPE
        INTEGER*2 WIDTH
        INTEGER*4 BASIC,EXTENDED
        END STRUCTURE
        RECORD /CHARACTERISTICS/ CHARBUF
C
        INTEGER*4 SYS$QIOW
        INTEGER*4 STATUS
C
C GET CHARACS NOW.
        STATUS=SYS$QIOW(,
     1  %VAL(CHANNEL),
     2  %VAL(IO$_SENSEMODE),
     3  IOSB,,,
     4  CHARBUF,
     5  %VAL(12),,,,) ! 12 BYTE BUFFER
C
        IF(.NOT.STATUS)CALL LIB$SIGNAL(%VAL(STATUS))
        IF(.NOT. IOSB.IOSTAT)CALL LIB$SIGNAL(%VAL(IOSB.IOSTAT))
C
C RETURN TERM CHARACS TO CALLER
        CLASS = CHARBUF.CLASS
        TYPE = CHARBUF.TYPE
        WIDTH = CHARBUF.WIDTH
        BASIC = CHARBUF.BASIC
        EXTENDED = CHARBUF.EXTENDED
        RETURN
        END
        SUBROUTINE SET_TERMINAL_CHARACTERISTICS (CHANNEL,
     1  CLASS, TYPE, WIDTH, BASIC,EXTENDED)
C
C SETS TERMINAL CHARS IN INPUTS BASIC, EXTENDED.
        INTEGER*2 CHANNEL
        BYTE CLASS
        BYTE TYPE
        INTEGER*2 WIDTH
        INTEGER*4 BASIC,EXTENDED
C
C I/O OP DEFS
        INCLUDE '($IODEF)'
C QIO STAT BLK
        STRUCTURE /IOSTAT_BLOCK/
        INTEGER*2 IOSTAT
        BYTE TRANSMIT,RECEIVE,CRFILL,LFFILL,PARITY,ZERO
        END STRUCTURE
        RECORD /IOSTAT_BLOCK/ IOSB
C
C CHARAC. BUFFER
        STRUCTURE /CHARACTERISTICS/
        BYTE CLASS,TYPE
        INTEGER*2 WIDTH
        INTEGER*4 BASIC,EXTENDED
        END STRUCTURE
        RECORD /CHARACTERISTICS/ CHARBUF
C
        INTEGER*4 SYS$QIOW
        INTEGER*4 STATUS
C SET APPROPRIATE CHARACTERISTICS FROM CALLER NOW
        CHARBUF.CLASS = CLASS
        CHARBUF.TYPE = TYPE
        CHARBUF.WIDTH=WIDTH
        CHARBUF.BASIC= BASIC
        CHARBUF.EXTENDED = EXTENDED
C
C GET CHARACS NOW.
        STATUS=SYS$QIOW(,
     1  %VAL(CHANNEL),
     2  %VAL(IO$_SETMODE),
     3  IOSB,,,
     4  CHARBUF,
     5  %VAL(12),,,,) ! 12 BYTE BUFFER
C
        IF(.NOT.STATUS)CALL LIB$SIGNAL(%VAL(STATUS))
        IF(.NOT. IOSB.IOSTAT)CALL LIB$SIGNAL(%VAL(IOSB.IOSTAT))
C
        RETURN
        END