INTRODUCTION
4110 Series raster display terminals can be used for screen editing by placing them in ANSI mode. In ANSI mode, termi-nal's ANSI parser responds to a subset of the ANSI X3.64 command set; the terminal no longer recognizes the 4110 Series command set. DVST terminals do not contain an ANSI parser.
You can put a 4110 Series raster terminal into ANSI mode from TEK mode or TEK mode from ANSI mode with the SELECT-CODE command. You specify the mode to enter by the parameter; 0 specifies TEK mode, and 1 specifies ANSI mode.
Most screen editors include a terminal initialization file. The terminal initialization file should include the TEK mode com-mands to make the dialog area visible and set the dialog area buffer to the correct size to work with your screen editor. It is not necessary to enable the dialog area, Since the ANSI parser automatically directs all commands, includ-ing alphatext, to the dialog area.
PREVIEW
This discussion includes:
• Screen editor basics
• Cursor positioning commands
• Tabulation commands
• Editing commands
CONCEPTS AND DEFINITIONS Screen Editors
A screen editor is a host program that displays a copy of the text that the operator is working on. The operator has the illusion of directly entering and editing the text. Most screen editors do not totally redraw the display each time the oper-ator changes something. Instead, they maintain a copy of the terminal display in a buffer which they update in the same way the terminal updates its display in response to the operator. The only communication between the host and the terminal is the transmission of the commands and char-acters that are changed.
4110 Series terminals implement a large enough subset of the ANSI X3.64 standard commands to allow the use of most purchased screen editors.
Cursor Positioning
The cursor is the marker used by the terminal to show where the next editing command will take place. The cursor posi-tion is the line and column number that define the position of the cursor where (0,0) is the upper left corner of the dialog area.
The cursor positioning commands are:
• CURSOR-FORWARD (CUF) - move the cursor n col-umns to the right on the current line
• CURSOR-BACKWARD (CUB) - move the cursor n col-umns to the left on the current line
• CURSOR-UP (CUU) - move the cursor up the specified number of lines
• CURSOR-DOWN (CUD) - move the cursor down the specified number of lines
• CURSOR-POSITION (CUP) - move the cursor to the specified line and column
• HORIZONTALANDVERTICALPOSITION (HVP) -nearly identical to CURSOR-POSITION
• NEXT-LINE (NEL) - move the cursor to the beginning of the next line
4110 SERIES HOST
OPERATOR INTERFACE
• INDEX (IND) move the cursor down one line and keep the current column position
• REVERSE-INDEX (RI) - move the cursor up one line and keep the current column position
• cR character - obeys the CRLF setting
• FF character - nearly identical to INDEX
• LF character - obeys the LFCR setting
• vT character - nearly identical to INDEX
• HT character - move the cursor to the next horizontal tab stop no wrap-around
• CURSOR-BACKWARD-TAB (CBT) - moves the cursor backward n tab stops on current line with no wrap-around
• CURSOR-HORIZONTAL-TAB (CHT) - moves the cursor forward n tab stops with no wrap around Tabulation Commands
Tabulation commands move the cursor between tab stops and allow you to set and delete tab stops. 4110 Series
ter-minas support only horizontal tabs.
• HORIZONTAL-TAB-SET (HTS) - set a tab stop at the current cursor position
• TABULATION-CLEAR (TBC) - clear tab stops accord-ing to the parameter settaccord-ing: 1 - clear the tab stop at current position 2 - clear all tab stops in the active line (same as 3) 3 - same as 2
• HT character - move the cursor to the next tab stop in current line
• CURSOR-BACKWARD-TAB (CBT) - moves the cursor backward n tab stops on current line with no wrap-around
• CURSOR-HORIZONTAL-TAB (CHT) --'- moves the cursor forward n tab stops no wrap around
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OPERATOR INTERFACE
Editing Commands
Editing commands are of three types: insertion, deletion, and erase. Insertion commands, as their name implies insert blanks at and to the right of the cursor. Text after the cursor is moved to give room for the insertion. Deletion commands remove text from the vicinity of the cursor, and remaining text is pulled in to close the gap. Erasing commands are similar to deletion commands, but the gap is not closed.
Erased text is replaced by blanks.
The 4110 ANSI mode editing commands are:
• INSERT-CHARACTER (ICH) - shifts characters at and to the right of the cursor n positions to the right
• INSERT-LINE - inserts n blank lines at the cursor position
• DELETE-CHARACTER (DCH) - deletes n characters from the line to the right of the cursor
• DELETE-LINE (DL) - deletes n lines beginning at the cursor
• ERASE-CHARACTER (ECH) - erase n characters leav-ing blanks does not move text wraps to next line
• ERASE-IN-DISPLAY (ED) - deletes characters accord-ing to the parameter:
0 - from cursor through end of scroll, including cursor 1 - from beginning through and including cursor 2 - erases entire scroll buffer
Display Control Commands
• SAVE-CURSOR (TEKSC)...,- terminal saves current cursor position and graphic rendition, or text style
• RESTORE-CURSOR (TEKRC) - Restores cursor posi-tion and graphic rendiposi-tion saved with SAVE-CURSOR command
• SCROLL-DOWN (SD) - moves scroll buffer down n lines within dialog area does not move cursor - cursor may move out of view
• SCROLL-UP (SU) - moves scroll buffer up n lines within dialog area does not move cursor - cursor may move out of view
• SELECT-CHARACTER-SET (SCS) - no-op, included for compatibility with other terminals
• SELECT-GRAPHIC-RENDITION (SGR) - selects the style(s) for displaying text characters
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Terminal Control Commands
• ANSI/VT52-MODE (TECKANM) - 4110 Series termi-nals do not include this mode. The command is a no-op for compatibility with some editors.
• DISABLE-MANUAL-INPUT (DMI) - locks the terminal keyboard and prevents operator from sending any characters
• ENABLE-MANUAL-INPUT (EMI) - unlocks terminal keyboard
• SET-MODE (SM) - sets the terminal mode selected by the parameter(s)
• RESET-MODE (RM) - resets the terminal mode se-lected by the parameter(s)
• RESET-TO-INITIAL-STATE (RIS) - causes terminal to perform a power-up reset. The effect is the same as pressing the MASTER RESET key or issuing the T4100 RESET command.
Communications
• DEVICE-STATUS-REPORT (DSR) - causes the termi-nal to send a device status report of the current cursor position se-lected by the parameter(s)
The modes affected by the SET-MODE and RESET-MODE commands are: