Table of Contents

CTerm

CTerm is the ANSI parsing code maintained as part of ciolib (and used by SyncTERM). This page is basically a pretty version of the cterm.txt file in git, as of 7a8edde4c8ccdedd1556895eec3ed265a4f615bf

The text file is still the normative reference, but this may serve as a friendlier source.

CTerm terminal characteristics

End of line behaviour (wrapping)

The cursor is moved to the first character of the next line as soon as a character is written to the last column of the current line, not on the next character. A tab will wrap to the next line only if the current cursor position is the last character on the line. This behavior is often surprising to people who are used to VT emulators which implement the LCF as documented in STD-070, who expect the cursor to “stick” in the last column until the next character is received.

There are two settable flags that will impact the default behaviour.

CSI ? 7 l will disable wrapping at the end of line completely, and any characters written to the last column will not move the cursor at all, overwriting the existing charater. Default behaviour can be restored with CSI ? 7 h.

If the CSI = 4 h sequence is received, CTerm will enable LCF mode as documented in STD-070, and CSI = 4 l will restore default behaviour. CSI = 5 h will set LCF mode and disable CSI = 4 l, as well as cause LCF to remain enabled across an ESC c (RIS).

Specifically, the LCF will be set when displaying a printable character advances the cursor to the right margin, and cleared by any of the following being received: CSI ? 6 h, CSI ? 6 l, CSI ? 7 l, CSI @, CSI A, CSI B, CSI a, CSI j, CSI H, CSI f, CSI I, CSI Y, CSI J, CSI K, CSI P, CSI X, CSI r, ESC E, ESC M, CR, LF, BS, TAB, Any normal printable character when the cursor is at the right margin (of the screen or scrollable area).

Control Characters

Name Hex Description
NUL 0x00 No action is taken unless doorway mode is enabled. In doorway mode, indicates that the next character is a literal character. The IBM CP437 character will be displayed. This allows ESC and other control characters to be placed on the screen.
BEL 0x07 Terminal will beep
BS 0x08 Non-destructive backspace. Moves cursor position to the previous column unless the current column is the first, in which case no operation is performed.
HT 0x09 Moves to the next horizontal tab stop. Does not overwrite any characters in between. If there are no tab stops left in the line, moves to the first position of the next line. If the starting position is on the last line, will perform a scroll, filling the new line at bottom with the current attribute.
LF 0x0A Move cursor position to same column of the next row. If current row is the last row, scrolls the screen up and fills the new row with the current attribute.
CR 0x0D Move cursor position to column 1 of the current line
ESC 0x1B Introduces a control code. The ESC and the next byte together form the control code. If the control code is not valid, the ESC is ignored.

Control Codes

Control codes are in the following format: ESC {'0' (ZERO) to '~'} Legal combinations which are not handled are silently dropped.

Mnemonic Name Sequence Description
NEL Next Line ESC E Moves to the line home position of the next line. (Same as CR LF)
HTS Set Tab ESC H Sets a tab stop at the current column. ECMA-048
RI Reverse Line Feed ESC M Move up one line. ECMA-048
DCS Device Control String ESC P Begins a string consisting of the characters 0x08 - 0x0d and 0x20-0x7e, terminated by a String Terminator (ST)
SOS Start of String ESC X As the above strings, but may contain any characters except a Start Of String sequence or a String Terminator sequence. The string is currently ignored.
CSI Control Sequence Introducer ESC [ Introduces a control sequence. If the control valid, but not supported the CSI is ignored. If the control sequence is not valid, it is displayed
ST String Terminator ESC \ Ends a string sequence
OSC Operating System Command ESC ] Begins a string consisting of the characters 0x08 - 0x0d and 0x20-0x7e, terminated by a String Terminator (ST)
PM Privacy Message ESC ^ Begins a string consisting of the characters 0x08 - 0x0d and 0x20-0x7e, terminated by a String Terminator (ST) The string is currently ignored.
APS Application Program String ESC _ Begins a string consisting of the characters 0x08 - 0x0d and 0x20-0x7e, terminated by a String Terminator (ST)
RIS Reset to Initial State ESC c Resets all the terminal settings, clears the screen, and homes the cursor.

Supported DCS string values

CTerm loadable font

Sequence: DCS CTerm:Font:p1:<b64> ST
Indicates the string is a loadable font. (CTerm 1.213)

p1 is a font slot number, which must be higher than the last default defined font (See CSI sp D for list of predefined fonts). <b64> is the base64 encoded font data. Font size is deduced from the size of the data. This replaces the now deprecated CSI = Ps1 ; Ps2 {

Sixel Sequence

Sequence: DCS [ p1 [ ; p2 ] ] q ST
Defaults: p1 = 0 p2 = 0
Indicates the string is a sixel sequence.

p1 selects the vertical height of a single pixel. This may be overridden by the raster attributes command, and is deprecated.

Supported values

Value Vertical Size
0,1,5,6 2 pixels
2 5 pixels
3,4 3 pixels
7,8,9 1 pixel

p2 indicates if unset sixels should be set to the current background colour. If p2 is 1, positions specified as 0 remain at their current colour.

Any additional parameters are ignored.

The rest of the string is made up of sixel data characters and sixel control functions. Sixel data characters are in the rage of '?' (0x3f) to '~' (0x7e). Each sixel data character represents six vertical pixels. The data is extracted by subtracting 0x3f from the ASCII value of the character. The least significant bit is the topmost pixel.

Sixel Control Functions
String Name Description
! Pn X Graphics Repeat Introducer The character X is repeated Pn times.
p1 ; p2 [ ; p3 [ ; p4 ] ] Raster Attributes p1 indicates the vertical size in pixels of each sixel.
p2 indicates the horizontal size in pixels.
p3 and p4 define the height and width (in sixels) respectively of a block to fill with the background colour. This block may not extend past the current bottom of the screen. If any pixel data characters proceed this command, it is ignored.
# p1 Colour Select Selects the current foreground colour from the sixel palette.
# p1 ; p2 ; p3 ; p4 ; p5 Palette map Defines sixel palette entry p1 and sets it as the current foreground colour. p2 specifies the colour space to define the colour in, the only supported value is 2. p3, p4, and p5 specify the red, green, and blue content as a percentage (0-100).
$ Graphics Carriage Return Returns the active position to the left border of the same sixel row. Generally, one pass per colour is used. In passes after the first one, sixels with a value of zero are not overwritten with the background colour.
- Graphics New Line Moves the active position to the left border of the next sixel row.

Request Status String (DECRQSS)

Sequence: DCS $ q pt ST
pt is the intermediate and/or final characters of a control function to query the status of. The terminal will send a response in the format DCS p1 $ r pt ST

p1 is 1 if the terminal supports querying the control function and 0 if it does not.

pt is the characters in the control function except the CSI characters.

Currently supported values of p1:

Value Description
m Request SGR parameters
r Request top and bottom margins
s Request left and right margins
t Request height in lines
$| Request width in columns
*| Request height in lines

Define Macro (DECDMAC)

Sequence: DCS p1 [ ; p2 [ ; p3 ] ! z ST
Defaults: p2 = 0 p3 = 0
Sets a macro to be replayed using CSI Pn * z

p1 is the macro number to set, and make be between 0 and 63 inclusive.

If p2 is zero, the macro numbered p1 will be deleted. If p2 is one, all macros are deleted.

If p3 is zero, the macro is defined using ASCII characters (0x20 - 0x7e and 0xa0 - 0xff only) if p3 is one, the macro is defined using hex pairs.

When the macro is defined using hex pairs, a repeat sequence may be included in the format of ! Pn ; D..D ;. Pn specifies the number of repeats (default of one instance) D..D is the sequence of pairs to send Pn times. The terminating ; may be left out if the sequence to be repeated ends at the end of the string.

Supported OSC string values

Palette Redefinition

Sequence: OSC 4;(pX;pY)... ST
Specifies one or more palette redefinitions. pX is the palette index, and pY is the colour definition Color format: rgb:R/G/B Where R, G, and B are a sequence of one to four hex digits representing the value of the red, green, and blue channels respectively.

Supported APS string values

SyncTERM implements the following APS commands:

Store File

Sequence: APS SyncTERM:C;S Ps1 Ps2 ST
Where Ps1 is a filename and Ps2 is the base64 encoded contents of the file. The named file is stored in the cache directory for the current connection.

List Files in Cache

Sequence: APS SyncTERM:C;L Ps ST
List files in cache. SyncTERM responds with an APS string with lines separated by newlines. The first line is always “SyncTERM:C;L\n” and for each matching file, a line in the form <Filename> TAB <MD5 sum> LF is sent (ie: “coolfont.fnt\t595f44fec1e92a71d3e9e77456ba80d1\n”)

And additional argument can be specified as a glob(3) pattern (defaults to “*”) in APS SyncTERM:C;L;Ps ST.

Set Font

Sequence: APS SyncTERM:C;SetFont Pn Ps ST
Where Pn is a font slot number (max 255) and Ps is a filename in the cache. This sets font slot Pn to use the specified font file.

Draw PPM

Sequence: APS SyncTERM:C;DrawPPM Ps... Ps2 ST
Draws a PPM from the cache directory on the screen. Ps2 is the filename and is required. Arguments for Ps are optional. The following options can be included (separated by semi-colons):

Option Description
SX=# Sets the left X position in the specified image to copy from. Default = 0.
SY=# Sets the top Y position in the specified image to copy from. Default = 0.
SW=# Sets the width of the portion of the image to copy. Default = Image width - SX
SH=# Sets the height of the portion of the image to copy. Default = Image height - SH
DX=# Sets the X position on the screen to draw the image at. Default = 0.
DY=# Sets the Y position on the screen to draw the image at. Default = 0.
MX=# Sets the X position in the mask to start applying from. Default = 0.
MY=# Sets the Y position in the mask to start applying from. Default = 0.
MW=# Sets the overall width of the mask (not the width to apply). If MFILE is not specified, and a mask is (ie: using MASK=), this is required. If MFILE is specified, the width is read from the file.
MH=# Sets the overall height of the mask (not the height to apply). If MFILE is not specified, and a mask is (ie: using MASK=), this is required. If MFILE is specified, the width is read from the file.
MFILE=<filename> Specifies a filename in the cache directory of a PBM file specifying a mask of which pixels to copy. Any pixel set to black (ie: 1) in the PBM will be drawn from the source image. Pixels set to white (ie: 0) will be left untouched.
MASK=<maskbits> Specifies a base64-encoded bitmap, each set bit will be drawn from the source image, cleared bits will not be drawn. Requires MW= and MH= to be specified.
MBUF Uses the loaded mask buffer.

The PPM file may be raw (preferred) or text. SyncTERM does not support more than 255 values per colour channel and assumes it is correctly using the BT.709 gamma transfer.

Load PPM

Sequence: APS SyncTERM:C;LoadPPM Ps... Ps0 ST
Loads a PPM to a buffer. Ps0 is the filename

B=# Selects the buffer (0 or 1 only) to paste from.

Load PBM

Sequence: APS SyncTERM:C;LoadPBM Ps... Ps0 ST
Loads a PBM to a buffer. Ps0 is the filename

Copy

Sequence: APS SyncTERM:P;Copy Ps... ST
Copies a portion of the screen into an internal buffer for use with the Paste function. Defaults to copying the entire screen.

B=# Selects the buffer (0 or 1 only) to copy to.
X=# Sets the left X position on the screen to start copying at. Default = 0.
Y=# Sets the top Y position on the screen to start copying at. Default = 0.
W=# Sets the width to copy. Default = Screen width - X.
H=# Sets the height to copy. Default = Screen height - X.

Paste

Sequence: APS SyncTERM:P,Paste Ps... ST
Pastes from the copied buffer. Supports the same options as the Cache DrawPPM command except for the filename, and adds the B= option.

B=# Selects the buffer (0 or 1 only) to paste from.

Control Sequences

Control sequences are in the following format: CSI {'0' (ZERO) to '?'}{SPACE to '/'}{'@' to '~'} There may be multiple characters from the {'0' (ZERO) to '?'} and {SPACE to '/'} before the terminating {'@' to '~'} character.

Legal combinations not handled are silently dropped. Illegal combinations are displayed.

Sequence Parameters

Parameters are expressed by the {'0' (ZERO) to '?'} character set. Sequences which use parameters use decimal parameters separated by a ';'. The use of a ':' from the set is reserved. If the parameter string begins with '<', '=', '>', or '?' then this is a non-standard extension to the ANSI spec.

Pn Indicates a single numeric parameter
Pn1 ; Pn2 Two numeric parameters
Pn... Any number of numeric parameters
Ps Single selective parameter
Ps1 ; Ps1 Two selective parameters
Ps... Any numer of selective parameters

If a default is defined, the parameter is optional

Insert Character(s) (ICH)

Sequence: CSI Pn @
Defaults: Pn = 1
Moves text from the current position to the right edge Pn characters to the right, with rightmost characters going off-screen and the resulting hole being filled with the current attribute.

Scroll Left (SL)

Sequence: CSI Pn SP @
Defaults: Pn = 1
Shifts the contents of the screen left Pn columns(s) with leftmost columns going off-screen and the resulting hole being filled with the current attribute.

Cursor Up (CUU)

Sequence: CSI Pn A
Defaults: Pn = 1
Moves the cursor position up Pn lines from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Scroll Right (SR)

Sequence: CSI Pn SP A
Defaults: Pn = 1
Shifts the contents of the screen right Pn columns(s) with rightmost columns going off-screen and the resulting hole being filled with the current attribute.

Cursor Down (CUD)

Sequence: CSI Pn B
Defaults: Pn = 1
Moves the cursor position down Pn lines from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Cursor Right (CUF)

Sequence: CSI Pn C
Defaults: Pn = 1
Moves the cursor position right Pn columns from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Cursor Left (CUB)

Sequence: CSI Pn D
Defaults: Pn = 1
Moves the cursor position left Pn columns from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Font Selection (FNT)

Sequence: CSI Ps1 ; Ps2 SP D
Defaults: Ps1 = 0, Ps2 = 0
Sets font Ps1 to be the one indicated by Ps2. Currently four fonts are supported. Ps2 must be between 0 and 255. Not all output types support font selection. Only X11 and SDL currently do.

Supported Ps1 values:

0 Default font
1 Font selected by the high intensity bit when CSI ? 31 h is enabled
2 Font selected by the blink intensity bit when CSI ? 34 h is enabled
3 Font selected by both the high intensity and blink bits when both CSI ? 31 h and CSI ? 34 h are enabled

Currently included fonts are:

0 Codepage 437 English
1 Codepage 1251 Cyrillic, (swiss)
2 Russian koi8-r
3 ISO-8859-2 Central European
4 ISO-8859-4 Baltic wide (VGA 9bit mapped)
5 Codepage 866 © Russian
6 ISO-8859-9 Turkish
7 haik8 codepage (use only with armscii8 screenmap)
8 ISO-8859-8 Hebrew
9 Ukrainian font koi8-u
10 ISO-8859-15 West European, (thin)
11 ISO-8859-4 Baltic (VGA 9bit mapped)
12 Russian koi8-r (b)
13 ISO-8859-4 Baltic wide
14 ISO-8859-5 Cyrillic
15 ARMSCII-8 Character set
16 ISO-8859-15 West European
17 Codepage 850 Multilingual Latin I, (thin)
18 Codepage 850 Multilingual Latin I
19 Codepage 885 Norwegian, (thin)
20 Codepage 1251 Cyrillic
21 ISO-8859-7 Greek
22 Russian koi8-r ©
23 ISO-8859-4 Baltic
24 ISO-8859-1 West European
25 Codepage 866 Russian
26 Codepage 437 English, (thin)
27 Codepage 866 (b) Russian
28 Codepage 885 Norwegian
29 Ukrainian font cp866u
30 ISO-8859-1 West European, (thin)
31 Codepage 1131 Belarusian, (swiss)
32 Commodore 64 (UPPER)
33 Commodore 64 (Lower)
34 Commodore 128 (UPPER)
35 Commodore 128 (Lower)
36 Atari
37 P0T NOoDLE (Amiga)
38 mO'sOul (Amiga)
39 MicroKnight Plus (Amiga)
40 Topaz Plus (Amiga)
41 MicroKnight (Amiga)
42 Topaz (Amiga)

Not all fonts are supported in all modes. If a font is not supported in the current mode, no action is taken, but there should be a non-zero 'Font Selection result' value in the Font State Report.

Cursor Next Line (CNL)

Sequence: CSI Pn E
Defaults: Pn = 1
Moves the cursor to the first column of the line Pn down from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Cursor Preceding Line (CPL)

Sequence: CSI Pn F
Defaults: Pn = 1
Moves the cursor to the first column of the row Pn up from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Cursor Character Absolute (CHA)

Sequence: CSI Pn G
Defaults: Pn = 1
Movies the cursor to column Pn of the current row.

Cursor Position (CUP)

Sequence: CSI Pn1 ; Pn2 H
Defaults: Pn = 1, Pn2 = 1
Moves the cursor to the Pn2th column of the Pn1th line.

Cursor Forward Tabulation (CHT)

Sequence: CSI Pn I
Defaults: Pn = 1
Move the cursor to the Pn-th next tab stop. Basically the same as sending TAB Pn times.

Erase in Page (ED)

Sequence: CSI Ps J
Defaults: Ps = 0
Erases from the current screen according to the value of Ps

0 Erase from the current position to the end of the screen.
1 Erase from the current position to the start of the screen.
2 Erase entire screen. As a violation of ECMA-48, also moves the cursor to position 1/1 as a number of BBS programs assume this behaviour.

Erased characters are set to the current attribute.

Erase in Line (EL)

Sequence: CSI Ps K
Defaults: Ps = 0
Erases from the current line according to the value pf Ps

0 Erase from the current position to the end of the line.
1 Erase from the current position to the start of the line.
2 Erase entire line.

Erased characters are set to the current attribute.

Insert Line(s) (IL)

Sequence: CSI Pn L
Defaults: Pn = 1
Inserts Pn lines at the current line position. The current line and those after it are scrolled down and the new empty lines are filled with the current attribute. If the cursor is not currently inside the scrolling margins, has no effect.

Delete Line(s) / "ANSI Music" (DL)

Sequence: CSI Pn M
Defaults: Pn = 1
Deletes the current line and the Pn - 1 lines after it scrolling the first non-deleted line up to the current line and filling the newly empty lines at the end of the screen with the current attribute. If the cursor is not currently inside the scrolling margins, has no effect. If “ANSI” Music is fully enabled (CSI = 2 M), performs “ANSI” music instead. See “ANSI” MUSIC section for more details.

CTerm Set ANSI Music (CTSAM)

Sequence: CSI = Ps M
Defaults: Ps = 0
Sets the current state of ANSI music parsing.

0 Only CSI | will introduce an ANSI music string.
1 Both CSI | and CSI N will introduce an ANSI music string.
2 CSI |, CSI N, and CSI M will all introduce an ANSI music string. In this mode, Delete Line will not be available.

BananaCom ANSI Music (BCAM)

Sequence: CSI N
If “ANSI” Music is set to BananaCom (CSI = 1 M) or fully enabled (CSI = 2 M) performs “ANSI” music. See “ANSI” MUSIC section for more details.

Delete Character (DCH)

Sequence: CSI Ps P
Defaults: Pn = 1
Deletes the character at the current position by shifting all characters from the current column + p1 left to the current column. Opened blanks at the end of the line are filled with the current attribute. If the cursor is not currently inside the scrolling margins, has no effect.

Scroll Up (SU)

Sequence: CSI Ps S
Defaults: Pn = 1
Scrolls the screen up Pn lines. New lines emptied at the bottom are filled with the current attribute.

XTerm Set or Request Graphics Attribute (XTSRGA)

Sequence: CSI ? Ps1 ; Ps2 S
Defaults: None
If Ps1 is 2, and Ps2 is 1, replies with the graphics screen information in the following format: CSI ? 2 ; 0 ; Px ; Py S Where Px is the width of the screen in pixels and Py is the height.

Scroll Down (SD)

Sequence: CSI Pn T
Defaults: Pn = 1
Scrolls all text on the screen down Pn lines. New lines emptied at the top are filled with the current attribute.

Erase Character (ECH)

Sequence: CSI Pn X
Defaults: Pn = 1
Erase p1 characters starting at the current character. Will not erase past the end of line. Erased characters are set to the current attribute. This can erase across scroll margins.

Cursor Line Tabulation (CVT)

Sequence: CSI Pn Y
Defaults: Pn = 1
Move the cursor to the Pn-th next tab stop. Basically the same as sending TAB Pn times.

Cursor Backward Tabulation (CBT)

Sequence: CSI Pn Z
Defaults: Pn = 1
Move the cursor to the p1th preceding tab stop. Will not go past the start of the line.

Character Position Absolute (HPA)

Sequence: CSI Pn `
Defaults: Pn = 1
Move the cursor to the specified position on the current row. Will not go past the end of the line.

Cursor Position Forward (HPR)

Sequence: CSI Pn a
Defaults: Pn = 1
Moves the cursor position forward Pn columns from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Repeat (REP)

Sequence: CSI Pn b
Defaults: Pn = 1
Repeats the previous graphic character Pn times. Will not repeat escape sequences.

Device Attributes (DA)

Sequence: CSI Ps c
Defaults: Ps = 0
If Ps is 0, CTerm will reply with the sequence: CSI = 67;84;101;114;109;pN c. 67;84;101;114;109 is the ASCII values of the “CTerm” string. pN is the revision ID of CTerm with dots converted to semi-colons (e.g. “1;156”). Use the revision to detect if a specific feature is available. If you are adding features to a forked version of cterm, please do so by adding an extra parameter to the end, not by incrementing any existing one!

CTerm Device Attributes (CTDA)

Sequence: CSI < Ps c
Defaults: Ps = 0
If Pn is 0, CTerm will reply with the sequence: CSI < 0 ; Ps... c

Possible values for Ps:

1 Loadable fonts are availabe via Device Control Strings
2 Bright Background (ie: DECSET 32) is supported
3 Palette entries may be modified via an Operating System Command string
4 Pixel operations are supported (currently, sixel and PPM graphics)
5 The current font may be selected via CSI Ps1 ; Ps2 SP D
6 Extended palette is available
7 Mouse is available

Line Position Absolute (VPA)

Sequence: CSI Pn d
Defaults: Ps = 1
Moves to row specified by Pn.

Tab Stop Remove (TSR)

Sequence: CSI Pn SP d
Defaults: None
Removes a tab stop at postion Pn.

Line Position Forward (VPR)

Sequence: CSI Pn e
Defaults: Pn = 1
Moves forward Pn rows.

Character and Line Position (HVP)

Sequence: CSI Pn1 ; Pn2 f
Defaults: Pn1 = 1, Pn2 = 1
Moves the cursor to the Pn2th column of the Pn1th line.

Tabulation Clear (TBC)

Sequence: CSI Ps g
Defaults: Ps = 0
Deletes tab stops according to the values of Ps:

0 Deletes tab stop at current position.
3 Deletes all tab stops.
5 Deletes all tab stops.

Enable DoorWay Mode (BCST) / CTerm Set (CTSET)

Sequence: CSI = Ps... h
Defaults: None
Sets the mode specified by Ps

4 Enable Last Column Flag mode (CTELCF)
5 Enabled Forced Last Column Flag mode (CTFLCF)
255 Enable DoorWay Mode (BDRWY)

DEC Private Mode Set (DECSET)

Sequence: CSI ? Ps... h
Defaults: None
Sets one or more mode. The following modes are supported:

Value Mnemonic Default Description
6 DECOM reset Enable origin mode. In this mode, position parameters are relative to the top left of the scrolling region, not the screen.
7 DECAWM set Enable auto wrap. This is the normal mode in which a write to the last column of a row will move the cursor to the start of the next line triggering a scroll if required to create a new line.
9 reset X10 compatible mouse reporting. Mouse button presses will send a CSI M <button> <x> <y> Where <button> is ' ' + button number (0-based) <x> and <y> are '!' + position (0-based)
25 DECTCEM set Display the cursor.
31 reset Enable bright alt character set. With this mode set, the bright (1) graphic rendition selects characters from an alternate character set.
32 reset Bright Intensity Disable. This makes the bright intensity bit not control the intensity. Mostly for use with CSI ? 31 h to permit fonts in the same colours.
33 reset Blink to Bright Intensity Background. With this mode set, the blink (5,6) graphic renditions cause the background colour to be high intensity rather than causing blink.
34 reset Enable blink alt character set. With this mode set, the blink (5, 6) graphic renditions selects characters from an alternate character set.
35 reset
67 DECBKM set DEC Backarrow Key Mode. When set, backspace sends the BS code. When reset, backspace sends DEL (0x7F).
69 reset DEC Left Right Margin Mode enabled. Enables CSI s to set the left/right margins, and disables CSI s from saving the current cursor position.
80 set Sixel Scrolling Enabled. When this is set, the sixel active position begins in the upper-left corner of the currently active text position. When the sixel active position reaches the bottom of the page, the page is scrolled up. At the end of the sixel string, a sixel newline is appended, and the current cursor position is the one in which the bottom sixel is in.
1000 reset Normal tracking mode mouse reporting. Mouse button presses will send a CSI M <button> <x> <y>. Where <button> is ' ' + button number (0-based). Mouse button releases will use a button number of 4 <x> and <y> are '!' + position (0-based)
1002 reset Button-event tracking mode mouse reporting. Mouse button presses and movement when a button is pressed will send a CSI M <button> <x> <y>, Where <button> is ' ' + button number (0-based). 32 is added to the button number for movement events. Mouse button releases will use a button number of 4 <x> and <y> are '!' + position (0-based)
1003 reset Any-event tracking mode mouse reporting Mouse button presses and movement will send a CSI M <button> <x> <y>. Where <button> is ' ' + button number (0-based) 32 is added to the button number for movement events. Mouse button releases will use a button number of 4 <x> and <y> are '!' + position (0-based) If no button is pressed, it acts as though button 0 is.
1006 reset SGR encoded extended coordinates. Instead of the CSI M method, the format of mouse reporting is changed to CSI < Pb ; Px ; Py M for presses and CSI < Pb ; Px ; Py m for releases. Instead of CSI M Px and Py are one-based. Pb remains the same (32 added for movement). Button 3 is not used for release (separate code).
2004 reset Set bracketed paste mode. CTerm does not directly do anything with this, but terminals such as SyncTERM will send CSI 200 ~ before pasted text, and CSI 201 ~ after it.

Character Position Backward (HPB)

Sequence: CSI Pn j
Defaults: Pn = 1
Moves the cursor position left Pn columns from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Line Position Backward (VPB)

Sequence: CSI Pn k
Defaults: Pn = 1
Moves the cursor position up Pn lines from the current position. Attempting to move past the screen boundaries stops the cursor at the screen boundary.

Disable DoorWay Mode (BCRST) / CTerm Set (CTRSET)

Sequence: CSI = Ps... l
Defaults: None
Resets the mode specified by Ps

4 Disable Last Column Flag mode (CTDLCF)
255 Disable DoorWay Mode (BDDRWY)

DEC Private Mode Reset (DECRST)

Sequence: CSI ? Ps... l
Defaults: None
Resets one or more mode. The following modes are supported:

Value Mnemonic Default Description
6 DECOM reset Origin Mode. With this mode reset, position parameters are relative to the top left of the screen, not the scrolling region.
7 DECAWM set Disable auto wrap. Resetting this mode causes a write to the last column of a to leave the cursor where it was before the write occurred, overwriting anything which was previously written to the same position.
9 reset Disable X10 compatible mouse reporting.
25 reset Hide the cursor.
31 reset Disable bright alt character set. With this mode reset, the bright (1) graphic rendition does not select an alternative font.
32 reset Bright Intensity Enable. When reset, bright intensity graphics rendition behaves normally.
33 reset Disable Blink to Bright Intensity Background. With this mode set, the blink (5,6) graphic renditions do not affect the background colour.
34 reset Disable blink alt character set. With this mode reset, the blink (5, 6) graphic renditions do not select characters from an alternate character set.
35 reset Blink Enable. With this mode reset, the blink (5,6) graphic renditions behave normally (cause the characters to blink).
69 reset DEC Left Right Margin Mode disabled. Disables CSI s from setting the left/right margins, and changes it back to saving the current cursor position. The current left/right margins are maintained.
80 set Sixel Scrolling Disabled. When this is reset, the sixel active position begins in the upper-left corner of the page. Any commands that attempt to advance the sixel position past the bottom of the page are ignored. At the end of the sixel string, the current cursor position is unchanged from where it was when the sixel string started.
1000 reset Disable Normal tracking mode mouse reporting
1001 reset Disable Highlight tracking mode mouse reporting
1002 reset Disable Button-event tracking mode mouse reporting
1003 reset Disable Any-event tracking mode mouse reporting
1004 reset Disable Focus-event tracking mode mouse reporting
1005 reset Disable UTF-8 encoded extended coordinates
1006 reset Disable SGR encoded extended coordinates
1007 reset Disable Alternate scroll mode
1015 reset Disable URXVT encoded extended coordinates
2004 reset Disable bracketed paste mode

Select Graphic Rendition (SGR)

Sequence: CSI Ps... m
Defaults: Ps1 = 0
Sets or clears one or more text attributes. Unlimited parameters are supported and are applied in received order. The following are supported:

Modified
Ps Description Blink Bold FG BG TF TB
0 Default attribute, white on black X X X X X X
1 Bright Intensity X X
2 Dim intensity X X
5 Blink (By definition, slow blink) X X
6 Blink (By definition, fast blink) X X
7 Negative Image - Reverses FG and BG X X X X
8 Concealed characters, sets the foreground colour to the background colour. X X X X
22 Normal intensity X X
25 Steady (Not blinking) X X
27 Positive Image - Restores FG and BG X X X X
30 Black foreground X X
31 Red foreground X X
32 Green foreground X X
33 Yellow foreground X X
34 Blue foreground X X
35 Magenta foreground X X
36 Cyan foreground X X
37 White foreground X X
38 Extended Foreground (see notes) X
39 Default foreground (same as white) X
40 Black background X X
41 Red background X X
42 Green background X X
43 Yellow background X X
44 Blue background X X
45 Magenta background X X
46 Cyan background X X
47 White background X X
48 Extended Background (see notes) X
49 Default background (same as black) X X
91 Bright Red foreground X X
92 Bright Green foreground X X
93 Bright Yellow foreground X X
94 Bright Blue foreground X X
95 Bright Magenta foreground X X
96 Bright Cyan foreground X X
97 Bright White foreground X X
100 Bright Black background X X X
101 Bright Red background X X X
102 Bright Green background X X X
103 Bright Yellow background X X X
104 Bright Blue background X X X
105 Bright Magenta background X X X
106 Bright Cyan background X X X
107 Bright White background X X X

All others are ignored.

Blink indicates the blink bit.
Bold indicates the bold bit.
FG indicates the foreground colour.
BG indicates the background colour.
TF indicates that the Tru Colour foreground is changed.
TB indicates that the Tru Colour background is changed.

NOTE: For 90-97, there is no effect unless bright foreground colours are enabled.

NOTE: For 100-107, there is no effect unless bright background colours are enabled.

NOTE: For 38 and 48, two additional formats are supported, a palette selection and a direct colour selection.

For palette selection, an additional two parameters are required after that value. They are considered part of the 38/48, not separate values. The first additional parameter must be a 5. The second additional parameter specified the palette index to use. To set the foreground to orange, and the background to a fairly dark grey, you would send: CSI 38 ; 5 ; 214 ; 48 ; 5 ; 238 m

The default palette is the XTerm 256-colour palette.

For direct colour selection, an additional four parameters are required after that value. They are considered part of the 38/48, not separate values. The first additional parameter must be a 2. The second, third, and fourth specify the R/G/B values respectively. CTerm handles this with an internal temporary palette, so scrollback may not have the correct colours. The internal palette is large enough for all cells in a 132×60 screen to have unique foreground and background colours though, so the current screen should always be as expected.

Device Status Report (DSR)

Sequence: CSI Ps n
Defaults: Ps = 0
A request for a status report. CTerm handles the following three requests:

5 Request a DSR CTerm will always reply with CSI 0 n indicating “ready, no malfunction detected”
6 Request active cursor position CTerm will reply with CSI y ; x R where y is the current line and x is the current row.
255 NON-STANDARD EXTENSION (BCDSR) Replies as though a CSI 6 n was received with the cursor in the bottom right corner. i.e.: Returns the terminal size as a position report.

CTerm Sate/Mode Request/Report (CTSMRR)

Sequence: CSI = Ps n
Defaults: Ps = 1
When Ps is 1, CTerm will respond with a Font State Report of the form CSI = 1 ;pF ;pR ;pS0 ;pS1 ;pS2 ;pS3 n where pF is the first available loadable-font slot number and pR is the result of the previous “Font Selection” request:

0 successful font selection
1 failed font selection
99 no font selection request has been received

pS0 - pS3 contain the font slots numbers of previously successful “Font Selection” requests into the 4 available alternate-font style/attribute values:

pS0 normal attribute font slot
PS1 high intensity foreground attribute font slot
PS2 blink attribute font slot
PS3 high intensity blink attribute font slot

When Ps is 2, CTerm will respond with a Mode Report of the form CSI = 2[;pN [;pN] [...]] n Where pN represent zero or more mode values set previously (e.g. via 'CSI ? pN h). Mode values cleared (disabled via CSI ? pN l) will not be included in the set of values returned in the Mode Report. If no modes are currently set, an empty parameter will be included as the first and only pN.

When Ps is 3, CTerm will respond with a Mode Report of the form CSI = 3 ; pH ; pW n Where pH is the height of a character cell in pixels, and pW is the width of a character cell in pixels.

When Ps is 4, CTerm will respond with a Mode Report of the form CSI = 4 ; pF n Where pF is 1 if LCF mode is enabled, and 0 if it is disabled.

When Ps is 5, CTerm will respond with a Mode Report of the form CSI = 5 ; pF n Where pF is 1 if LCF mode is forced, and 0 if it is not.

DEC Device STatus Report (DECDSR)

Sequence: CSI ? Ps [ ; Pn ] n
Defaults: Ps = 1, Pn = 1

When Ps is 62 (DECMSR) and there is no Pn, CTerm will respond with a Mode Report of the form CSI 32767 * { This indicates that 524,272 bytes are available for macro storage. This is not actually true, SyncTERM will use all available memory for macro storage, but some software checks this value, and some parsers don't allow more than INT16_MAX parameter values.

When Ps is 63 (DECCKSR) Pn defaults to 1, and CTerm will respond with a checksum of the defined macros in the form DCS Pn ! xxxx ST Where xxxx is the hex checksum.

DEC Set Top and Bottom Margins (DECSTBM)

Sequence: CSI Pn1 ; Pn2 r
Defaults: Pn1 = 1, Pn2 = last line on screen
Selects top and bottom margins, defining the scrolling region. Pn1 is the line number of the first line in the scrolling region. Pn2 is the line number of the bottom line.

DEC Select Communication Speed (DECSCS)

Sequence: CSI Ps1 ; Ps2 * r
Defaults: Ps1 = 0, Ps2 = 0
Set the output emulation speed (Select Communication Speed). If Ps1 or Ps2 are omitted, causes output speed emulation to stop. Ps1 may be empty. Sequence is ignored if Ps1 is not empty, 0, or 1. The value of Ps2 sets the output speed emulation as follows:

Value Speed
empty, 0 Unlimited
1 300
2 600
3 1200
4 2400
5 4800
6 9600
7 19200
8 38400
9 57600
10 76800
11 115200

CTerm Save Mode Setting (CTSMS)

Sequence: CSI ? Ps... s
Defaults: None
Saves the current mode states as specified by CSI ? l and CSI ? h. If Ps1 is omitted, saves all such states. If one or more values of Ps is included, saves only the specified states (arguments to CSI ? l and CSI ? h).

DEC Set Left and Right Margin (DECSLRM)

Sequence: CSI Pn1 ; Pn2 s
Defaults: Pn1 = 1, Pn2 = last column on screen
(Only when DEC Left Right Margin Mode - 69 - is enabled)
If either Pn1 or Pn2 is zero, the current setting is retained. Selects left and right margins, defining the scrolling region. Pn1 is the column number of the first column in the scrolling region. Pn2 is the column number of the right column.

SCO Save Cursor

Sequence: CSI s
Defaults: None
(Only when DEC Left Right Margin Mode - 69 - is disabled)
Saves the current cursor position for later restoring with CSI u although this is non-standard, it's so widely used in the BBS world that any terminal program MUST implement it.

CTerm 24=Bit Colour (CT24BC)

Sequence: CSI Ps ; Pn1 ; Pn2 ; Pn3 t
Defaults: None
Select a 24-bit colour. If Ps is 0, sets the background colour. If Ps is 1, sets the foreground colour. Pn1, Pn2, Pn3 contains the RGB value to set. CTerm handles this with an internal temporary palette, so scrollback may not have the correct colours. The internal palette is large enough for all cells in a 132×60 screen to have unique foreground and background colours though, so the current screen should always be as expected.

CTerm Restore Mode Setting (CTRMS)

Sequence: CSI ? Ps... u
Defaults: None
Restores the mode states as saved via CSI ? s. If Ps is omitted, restores all such states. If one or more values of Ps is included, restores all the specified states (arguments to CSI ? l/h)

SCO Restore Cursor (SCORC)

Sequence: CSI u
Defaults: None
Move the cursor to the last position saved by CSI s. If no position has been saved, the cursor is not moved.

DEC Tab Stop Report (DECTABSR)

Sequence: CSI 2 $ w
Defaults: None
Requests a list of tab stops. The list is in the form: DCS 2 $ u Pt ST. The string Pt is a list of tab stops separated by /.

DEC Request Checksum of Rectangular Area (DECRQCRA)

Sequence: CSI Pn1 ; Ps ; Pn2 ; Pn3 ; Pn4 ; Pn5 * y
Defaults: None
Returns a checksum for the specified rectangular area. Pn1 is an ID that is returned in the response. Ps MUST be 1. Pn2 specifies the top row of the rectangle. Pn3 specifies the left column of the rectangle. Pn4 specifies the bottom row of the rectangle. Pn5 specifies the right column of the rectangle. The return value is in the format of DCS Pn1 ! ~ xxxx ST where xxxx is the hex value of the checksum.

DEC Invoke Macro (DECINVM)

Sequence: CSI Pn1 ; Ps ; Pn2 ; Pn3 ; Pn4 ; Pn5 * y
Defaults: None
Invokes a macro. Pn specifies the macro number. If Pn is not 0..63, no action is taken.

CTerm Obsolete Send Font (CTOSF)

Sequence: CSI = Ps1 ; Ps2 {
Defaults: Ps1 = 255, PS2 = 0
This is a poorly defined command that violates the basic design laid out in ECMA-48. This will be removed in the next major version of CTerm, and should not be used.

Indicates that a font block is following. Ps1 indicates the font slot to place the loaded font into. This must be higher than the last default defined font (See CSI sp D for list of predefined fonts) Ps2 indicates font size according to the following table:

0 8×16 font, 4096 bytes.
1 8×14 font, 3584 bytes.
2 8×8 font, 2048 bytes.

The DCS font string should be used instead as of CTerm 1.213

"ANSI" Music

This is the place where the BBS world completely fell on it's face in ANSI usage. A programmer with either TeleMate or QModem (the first two programs to support “ANSI” music as far as I can tell) decided they needed a method of playing music on a BBS connection. They decided to add an “unused” ANSI code and go their merry way. Since their product didn't implement CSI M (Delete line) they assumed it was unused and blissfully broke the spec. They defined “ANSI” music as: CSI M <music string> 0x0e

They used a subset of IBM BASICs PLAY statement functionality for ANSI music strings which often start with “MF” or “MB”, so the M after the CSI was often considered as part of the music string. You would see things such as: CSI MFABCD 0x0e and the F would not be played as a note. This just added further confusion to the mess.

Later on, BananaCom realized the conflict between delete line and music, so they added *another* broken code CSI N (Properly, erase in field... not implemented in many BBS clients) which was to provide an “unbroken” method of playing music strings. They also used CSI Y to disambiguate delete line, CSI Y is supposed to be a vertical tab (also not implemented in very many clients). BananaCom also introduced many more non-standard and standard-breaking control sequences which are not supported by CTerm.

CTerm has further introduced a standard compliant ANSI music introducer CSI |

By default, CTerm allows both CSI N and CSI | to introduce a music string. Allowed introducers are set by CSI = p1 M as defined above.

The details of ANSI music then are as follows:
The following characters are allowed in music strings:
“aAbBcCdDeEfFgGlLmMnNoOpPsStT0123456789.-+#<> ” If any character not in this list is present, the music string is ignored as is the introducing code.

If the introducing code is CSI M the first char is examined, and if it is a one of “BbFfLlSs” or if it is “N” or “n” and is not followed by a decimal digit, then the music string is treated as though an M is located in front of the first character.

The music string is then parsed with the following sequences supported:

Mx sets misc. music parameters where x is one of the following:
F Plays music in the foreground, waiting for music to complete playing before more characters are processed.
B Play music in the background, allowing normal processing to continue.
N “Normal” not legato, not staccato
L Play notes legato
S Play notes staccato
T### Sets the tempo of the music where ### is one or more decimal digits. If the decimal number is greater than 255, it is forced to 255. If it is less than 32, it is forced to 32. The number signifies quarter notes per minute. The default tempo is 120.
O### Sets the octave of the music where ### is one or more decimal digits. If the decimal number is greater than 6, it is forced to 6.The default octave is 4.
N### Plays a single note by number. Valid values are 0 - 71. Invalid values are played as silence. Note zero is C in octave 0. See following section for valid note modifiers.
A,
B,
C,
D,
E,
F,
G,
P
Plays the named note or pause from the current octave. An “Octave” is the rising sequence of the following notes: C, C#, D, D#, E, F, F#, G, G#, A, A#, B. This is contrary to normal music terminology. The special note “P” is a pause. Notes may be followed by one or more modifier characters which are applied in order. If one overrides a previous one, the last is used. The valid modifiers are:
+ Sharp. The next highest semitone is played. Each sharp character will move up one semitone, so “C++” is equivalent to “D”.
# Sharp. The next highest semitone is played. Each sharp character will move up one semitone, so “C##” is equivalent to “D”.
- Flat. The next lowest semitone is played. Each flat character will move down one semitone, so “D–” is equivalent to “C”.
. Duration is 1.5 times what it would otherwise be. Dots are not cumulative, so “C..” is equivalent to “C.”
### Notelength as a reciprocal of the fraction of a whole note to play the note for. For example, 4 would indicate a ¼ note. The default note length is 4.
L### Set the notelength parameter for all following notes which do not have one specified (ie: override the quarter-note default) Legal note lengths are 1-64 indicating the reciprocal of the fraction (ie: 4 indicates a ¼ note).
< Move the next lowest octave. Octave cannot go above six or below zero.
> Move to the next highest octave. Octave cannot go above six or below zero.

The lowest playable character is C in octave zero. The frequencies for the six C notes for the seven octaves in rising order are:
65.406, 130.810, 261.620, 523.250, 1046.500, 2093.000, 4186.000

Purists will note that the lower three octaves are not exactly one half of the next higher octave in frequency. This is due to lost resolution of low frequencies. The notes *sound* correct to me. If anyone can give me an excellent reason to change them (and more correct integer values for all notes) I am willing to do that assuming the notes still sound “right”.

PLEASE NOTE!!! If you are playing some ANSI Music then ask the user if they heard it, ALWAYS follow it with an 0x0f as 0x0e is the shift lock character which *will* cause people with anything but an ANSI-BBS terminal (ie: *nix users using the bundled telnet app) to have their screen messed up. 0x0f “undoes” the 0x0e.

Key Sequences

While CTerm does not handle keyboard I/O, and therefore does not send any key sequences, it's only used by one piece of software (SyncTERM), which does send a set of sequences when keys are pressed. These are listed below for reference.

Left Arrow “\033[D”
Right Arrow “\033[C”
Up Arrow “\033[A”
Down Arrow “\033[B”
Home “\033[H”
End “\033[K”
Delete “\x7f”
Page Down “\033[U”
Page Up “\033[V”
F1 “\033[11~”
F2 “\033[12~”
F3 “\033[13~”
F4 “\033[14~”
F5 “\033[15~”
F6 “\033[17~” (Note the jump from 15 to 17 here)
F7 “\033[18~”
F8 “\033[19~”
F9 “\033[20~”
F10 “\033[21~”
F11 “\033[23~” (Note the jump from 21 to 23 here)
F12 “\033[24~”
Shift + F1 “\033[11;2~”
Shift + F2 “\033[12;2~”
Shift + F3 “\033[13;2~”
Shift + F4 “\033[14;2~”
Shift + F5 “\033[15;2~”
Shift + F6 “\033[17;2~”
Shift + F7 “\033[18;2~”
Shift + F8 “\033[19;2~”
Shift + F9 “\033[20;2~”
Shift + F10 “\033[21;2~”
Shift + F11 “\033[23;2~”
Shift + F12 “\033[24;2~”
Alt + F1 “\033[11;3~”
Alt + F2 “\033[12;3~”
Alt + F3 “\033[13;3~”
Alt + F4 “\033[14;3~”
Alt + F5 “\033[15;3~”
Alt + F6 “\033[17;3~”
Alt + F7 “\033[18;3~”
Alt + F8 “\033[19;3~”
Alt + F9 “\033[20;3~”
Alt + F10 “\033[21;3~”
Alt + F11 “\033[23;3~”
Alt + F12 “\033[24;3~”
Control + F1 “\033[11;5~”
Control + F2 “\033[12;5~”
Control + F3 “\033[13;5~”
Control + F4 “\033[14;5~”
Control + F5 “\033[15;5~”
Control + F6 “\033[17;5~”
Control + F7 “\033[18;5~”
Control + F8 “\033[19;5~”
Control + F9 “\033[20;5~”
Control + F10 “\033[21;5~”
Control + F11 “\033[23;5~”
Control + F12 “\033[24;5~”
Insert “\033[@”
Back Tab “\033[Z”

See Also

ref/cterm.txt · Last modified: 2024/02/12 10:12 by deuce
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