= CTerm Manual
:toc:

== 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).

== C0 Control characters

=== `0x00` NUL (`NUL`)
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.

SOURCE: <<BANSI>>

=== `0x07` Bell (`BEL`)
Beep

=== `0x08` Backspace (`BS`)
Non-destructive backspace.  Moves cursor position to
the previous column unless the current column is the
first, in which case no operation is performed.

SOURCE: <<ECMA-48>>

=== `0x09` Horizontal Tab (`HT`)
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.

SOURCE: <<ECMA-48>>

=== `0x0A` Line Feed (`LF`)
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.

SOURCE: <<ECMA-48>>

=== `0x0D` Carriage Return (`CR`)
Move cursor position to column 1 of the current line

SOURCE: <<ECMA-48>>

=== `0x1B` Escape (`ESC`)
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.

SOURCE: <<ECMA-48>>

== nF Escape Sequences

nF Escape Sequences are in the following format: +
`ESC {SPACE to '/}{'0'` to `'~'}` +
There may be multiple characters from the {SPACE to '/'} before the
terminating {'@' to '~'} character.

At present, CTerm does not support any nF escape sequences.

SOURCE: <<ECMA-35>>

== Fp Escape Sequences (Private control functions)

Private control functions are in the following format: +
`ESC {'0'` to `'?'}` +

SOURCE: <<ECMA-35>>

Legal combinations not handled are silently dropped.

=== `ESC 7` Save Cursor (`DECSC`)
Saves the current cursor position same as `CSI s`

SOURCE: <<VT102>>

=== `ESC 8` Restore Cursor (`DECRC`)
Restores the current cursor position same as `CSI u`

SOURCE: <<VT102>>

== Fe Escape Sequences (Control functions in the C1 set)

Control codes are in the following format: +
`ESC {'@'` to `'_'}`
Legal combinations which are not handled are silently dropped.

=== `ESC E` Next Line (`NEL`)
Moves to the line home position of the next line.
(Same as `CR` `LF`)

SOURCE: <<ECMA-48>>

=== `ESC H` Set Tab (`HTS`)
Sets a tab stop at the current column

SOURCE: <<ECMA-48>>

=== `ESC M` Reverse Line Feed (`RI`)
Move up one line

SOURCE: <<ECMA-48>>

=== `ESC P`	Device Control String (`DCS`)
Begins a string consisting of the characters 0x08 - 0x0d and
0x20-0x7e, terminated by a String Terminator (`ST`)

Introduces <<Device Control Strings>>

SOURCE: <<ECMA-48>>

=== `ESC X` Start Of String (`SOS`)
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.

SOURCE: <<ECMA-48>>

=== `ESC [` Control Sequence Introducer (`CSI`)
Introduces <<Control Sequences>>

=== `ESC \` String Terminator (`ST`)
Ends a string.

SOURCE: <<ECMA-48>>

=== `ESC ]` Operating System Command (`OSC`)
Begins a string consisting of the characters 0x08 - 0x0d and
0x20-0x7e, terminated by a String Terminator (ST)

Introduces <<Operating System Commands>>

SOURCE: <<ECMA-48>>

=== `ESC ^` Privacy Message (`PM`)
Begins a string consisting of the characters 0x08 - 0x0d and
0x20-0x7e, terminated by a String Terminator (`ST`)
The string is currently ignored.

SOURCE: <<ECMA-48>>

=== `ESC _` Application Program Command (`APC`)
Begins a string consisting of the characters 0x08 - 0x0d and
0x20-0x7e, terminated by a String Terminator (ST)

Introduces <<Application Program Commands>>

SOURCE: <<ECMA-48>>

== Fs Escape Sequences (Standardized single control functions)

Standardized single control functions are in the following format: +
`ESC {'\`'` to `'~'}` +

SOURCE: <<ECMA-35>>

Legal combinations not handled are silently dropped.

=== `ESC c` Reset to Initial State (`RIS`)
Resets all the terminal settings, clears the screen, and homes
the cursor.

SOURCE: <<ECMA-48>>

== Control Sequences

Control sequences start with the Control Sequence Introducer which is
`ESC [`.  `CSI` will be used to express this from now on.

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.

.Sequence Paramters
[%autowidth,cols="1,2"]
|===
|`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

=== `CSI Pn @` Insert Character(s) (`ICH`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn SP @` Scroll Left (`SL`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn A` Cursor Up (`CUU`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn SP A` Scroll Right (`SR`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn B` Cursor Down (`CUD`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn C` Cursor Right (`CUF`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn D` Cursor Left (`CUB`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Ps1 ; Ps2 sp D` Font Selection (`FNT`)
Defaults: `Ps1` = 0  Ps2 = 0
"sp" indicates a single space character.
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
[%autowidth,cols="1,2"]
|===
|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
[%autowidth,cols="1,2"]
|===
|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 (c) 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 (c)

|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.

SOURCE: <<ECMA-48>>

=== `CSI Pn E` Cursor Next Line (`CNL`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn F` Cursor Preceding Line (`CPL`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn G` Cursor Character Absolute (`CHA`)
Defaults: `Pn` = 1 +
Movies the cursor to column Pn of the current row.

SOURCE: <<ECMA-48>>

=== `CSI Pn1 ; Pn2 H` Cursor Position (`CUP`)
Defaults: `Pn1` = 1  `Pn2` = 1 +
Moves the cursor to the `Pn2`th column of the `Pn1`th line.

SOURCE: <<ECMA-48>>

=== `CSI Pn I` Cursor Forward Tabulation (`CHT`)
Defaults: `Pn` = 1 +
Move the cursor to the Pn-th next tab stop.
Basically the same as sending TAB Pn times.

SOURCE: <<ECMA-48>>

=== `CSI Ps J` Erase in Page (`ED`)
Defaults: `Ps` = 0 +
Erases from the current screen according to the value of `Ps`

[%autowidth,cols="1,2"]
|===
|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-048, 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.

SOURCE: <<ECMA-48>>, <<BANSI>>

=== `CSI Ps K` Erase in Line (`EL`)
Defaults: `Ps` = 0 +
Erases from the current line according to the value pf `Ps`

[%autowidth,cols="1,2"]
|===
|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.

SOURCE: <<ECMA-48>>

=== `CSI Pn L` Insert Line(s) (`IL`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn M` Delete Line(s) / "ANSI" Music (`DL`)
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), and no parameter is
specified, performs "ANSI" music instead.
See <<_ansi_music,"ANSI" MUSIC>> section for more details.

SOURCE: <<ECMA-48>>, <<BANSI>>

=== `CSI = Ps M` CTerm Set ANSI Music (`CTSAM`)
NON-STANDARD EXTENSION. +
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.

=== `CSI N` BananaCom ANSI Music (`BCAM`)
"ANSI" Music / Not implemented.
If "ANSI" Music is set to BananaCom (`CSI = 1 M`) or fully enabled
(`CSI = 2 M`) performs "ANSI" music.  See <<_ansi_music,"ANSI" MUSIC>> section for more
details.

SOURCE: <<BANSI>>

=== `CSI Pn P` Delete Character (`DCH`)
Defaults: `Pn` = 1 +
Deletes the character at the current position by shifting all
characters from the current column + `Pn` 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.

SOURCE: <<ECMA-48>>

=== `CSI Pn S` Scroll Up (`SU`)
Defaults: `Pn` = 1 +
Scrolls the screen up `Pn` lines.  New lines emptied at the
bottom are filled with the current attribute.

SOURCE: <<ECMA-48>>

=== `CSI ? Ps1 ; Ps2 S` XTerm Set or Request Graphics Attribute (`XTSRGA`)
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.

SOURCE: <<XTerm>>

=== `CSI Pn T` Scroll Down (`SD`)
Defaults: `Pn` = 1 +
Scrolls all text on the screen down `Pn` lines.  New lines emptied at the
top are filled with the current attribute.

SOURCE: <<ECMA-48>>

=== `CSI Pn X` Erase Character (`ECH`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn Y` Cursor Line Tabulation (`CVT`)
Defaults: `Pn` = 1 +
Move the cursor to the `Pn`-th next tab stop.
Basically the same as sending TAB `Pn` times.

SOURCE: <<ECMA-48>>

=== `CSI Pn Z` Cursor Backward Tabulation (`CBT`)
Defaults: `Pn` = 1 +
Move the cursor to the ``Pn``th preceding tab stop.  Will not go past the
start of the line.

SOURCE: <<ECMA-48>>

=== `CSI Pn `` Character Position Absolute (`HPA`)
Defaults: `Pn` = 1 +
Move the cursor to the specified position on the current row.
Will not go past the end of the line.

SOURCE: <<ECMA-48>>

=== `CSI Pn a` Cursor Position Forward (`HPR`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn b` Repeat (`REP`)
Defaults: `Pn` = 1 +
Repeats the previous graphic character `Pn` times.  Will not repeat
escape sequences.

SOURCE: <<ECMA-48>>

=== `CSI Ps c` Device Attributes (`DA`)
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!

SOURCE: <<ECMA-48>>

=== `CSI < Ps c` CTerm Device Attributes (`CTDA`)
Defaults: `Ps` = 0 +
If `Pn` is 0, CTerm will reply with the sequence:
`CSI < 0 ; Ps... c`

.Possible values for `Ps`
[%autowidth,cols="1,2"]
|===
|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
|===

=== `CSI PN d` Line Position Absolute (`VPA`)
Defaults: `Pn` = 1 +
Moves to row specified by `Pn`.

SOURCE: <<ECMA-48>>

=== `CSI Pn SP d` Tab Stop Remove (`TSR`)
Defaults: None +
Removes a tab stop at postion `Pn`.

SOURCE: <<ECMA-48>>

=== `CSI Pn e` Line Position Forward (`VPR`)
Defaults: `Pn` = 1 +
Moves forward Pn rows.

SOURCE: <<ECMA-48>>

=== `CSI Pn1 ; Pn2 f` Character and Line Position (`HVP`)
Defaults: `Pn1` = 1  `Pn2` = 1 +
Moves the cursor to the ``Pn``2th column of the ``Pn``1th line.

SOURCE: <<ECMA-48>>

=== `CSI Ps g` Tabulation Clear (`TBC`)
Defaults: `Ps` = 0 +
Deletes tab stops according to the values of `Ps`:

[%autowidth,cols="1,2"]
|===
|0
|Deletes tab stop at current position.

|3
|Deletes all tab stops.

|5
|Deletes all tab stops.
|===

SOURCE: <<ECMA-48>>

=== `CSI = 255 h` (`BCSET`)
NON-STANDARD EXTENSION +
Enable DoorWay Mode

SOURCE: <<BANSI>>

=== `CSI = 4 h` Enable Last Column Flag (`CTELCF`)
NON-STANDARD EXTENSION +
Enable Last Column Flag mode

=== `CSI = 5 h` Force Last Column Flag (`CTFLCF`)
NON-STANDARD EXTENSION +
Force Last Column Flag mode

=== `CSI ? Ps... h` Set Mode (DECSET)
NON-STANDARD EXTENSION +
Sets one or more mode.  The following modes are supported:

[%autowidth,cols="1,2"]
|===
|6
|Enable origin mode.

In this mode, position parameters are relative to the top left of
the scrolling region, not the screen.  Defaults to reset.

SOURCE: <<VT102>>
|7
|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.  Defaults to set.

SOURCE: <<VT102>>
|9
|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)

SOURCE: <<XTerm>>
|25
|Display the cursor.  Defaults to set.

SOURCE: <<VT320>>
|31
|Enable bright alt character set

With this mode set, the bright (1) graphic rendition selects
characters from an alternate character set.  Defaults to reset.
|32
|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.  Defaults to reset.
|33
|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.
Defaults to reset.
|34
|Enable blink alt character set

With this mode set, the blink (5, 6) graphic renditions selects
characters from an alternate character set.  Defaults to reset
|35
|Blink Disabled

This makes the blink (5, 6) graphic renditions not cause the
character to blink.  Mostly for use with `CSI ? 34 h` to permit
fonts to be used without blinking.  Defaults to reset.
|67
|When set, the backspace key sends a backspace character.

Defaults to set.
|69
|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
|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.
Defaults to set.

SOURCE: <<VT330340,[VT330/340]>>
|1000
|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)

SOURCE: <<XTerm>>
|1001
|Highlight tracking mode mouse reporting

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1002
|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)

SOURCE: <<XTerm>>
|1003
|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.

SOURCE: <<XTerm>>
|1004
|Focus-event tracking mode mouse reporting

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1005
|UTF-8 encoded extended coordinates

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1006
|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)

SOURCE: <<XTerm>>
|1007
|Alternate scroll mode

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1015
|URXVT encoded extended coordinates

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|2004
|Set bracketed paste mode

SOURCE: <<XTerm>>
|===

=== `CSI Pn j` Character Position Backward (`HPB`)
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.

SOURCE: <<ECMA-48>>

=== `CSI Pn k` Line Position Backward (`VPB`)
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.

SOURCE: <<ECMA-48>>

=== `CSI = 255 l` Disable DoorWay Mode (`BCRST`)
NON-STANDARD EXTENSION +

SOURCE: <<BANSI>>

=== `CSI = 4 l` (`CTDLCF`)
NON-STANDARD EXTENSION +
Disable Last Column Flag mode

=== `CSI ? Ps... l` Reset Mode (`DECRST`)
NON-STANDARD EXTENSION +
Resets one or more mode.  The following modes are supported:

[%autowidth,cols="1,2"]
|===
|6
|Origin Mode

With this mode reset, position parameters are relative to the
top left of the screen, not the scrolling region.  Defaults
to reset.

SOURCE: <<VT102>>
|7
|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.

SOURCE: <<VT102>>
|9
|Disable X10 compatible mouse reporting

|25
|Hide the cursor.  Defaults to set.

SOURCE: <<VT320>>
|31
|Disable bright alt character set

With this mode reset, the bright (1) graphic rendition does not
select an alternative font.  Defaults to reset.
|32
|Bright Intensity Enable

When reset, bright intensity graphics rendition behaves normally.
Defaults to reset.
|33
|Disable Blink to Bright Intensity Background

With this mode set, the blink (5,6) graphic renditions do not
affect the background colour.  Defaults to reset.
|34
|Disable blink alt character set

With this mode reset, the blink (5, 6) graphic renditions do not
select characters from an alternate character set.  Defaults to
reset.
|35
|Blink Enable

With this mode reset, the blink (5,6) graphic renditions behave
normally (cause the characters to blink).  Defaults to reset.
|67
|When reset, the backspace key sends a delete character.

Defaults to set.
|69
|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
|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.  Defaults to set.

SOURCE: <<VT330340,[VT330/340]>>
|1000
|Disable Normal tracking mode mouse reporting

SOURCE: <<XTerm>>
|1001
|Disable Highlight tracking mode mouse reporting

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1002
|Disable Button-event tracking mode mouse reporting

SOURCE: <<XTerm>>
|1003
|Disable Any-event tracking mode mouse reporting

SOURCE: <<XTerm>>
|1004
|Disable Focus-event tracking mode mouse reporting

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1005
|Disable UTF-8 encoded extended coordinates

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1006
|Disable SGR encoded extended coordinates

SOURCE: <<XTerm>>
|1007
|Disable Alternate scroll mode
(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|1015
|Disable URXVT encoded extended coordinates

(Not supported by SyncTERM)

SOURCE: <<XTerm>>
|2004
|Disable bracketed paste mode

SOURCE: <<XTerm>> <<Paste64>>
|===

=== `CSI Ps... m` Select Graphic Rendition (`SGR`)
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:
[%autowidth,cols="1,2,^3,^4,^5,^6,^7,^8"]
|===
|`Ps` |Description |Blink |Bold |FG |BG |TF |TB
|0
|Default attribute, white on black
|√
|√
|√
|√
|√
|√

|1
|Bright Intensity
| 
|√
| 
| 
|√
| 

|2
|Dim intensity (clears the bright attribute; equivalent to SGR 22
in PC text mode since there is no distinct dim state)
| 
|√
| 
| 
|√
| 

|5
|Blink (By definition, slow blink)
|√
| 
| 
| 
| 
|√

|6
|Blink (By definition, fast blink)

NOTE: Both blinks are the same speed.
|√
| 
| 
| 
| 
|√

|7
|Negative Image - Reverses FG and BG
| 
| 
|√
|√
|√
|√

|8
|Concealed characters, sets the

      foreground colour to the background
      colour.
| 
| 
|√
| 
|√
|√

|22
|Normal intensity
| 
|√
| 
| 
|√
| 

|25
|Steady (Not blinking)
|√
| 
| 
| 
| 
|√

|27
|Positive Image - Restores FG and BG

NOTE: This should be a separate
attribute than 7 but this
implementation makes them equal
| 
| 
|√
|√
|√
|√

|30
|Black foreground
| 
| 
|√
| 
|√
| 

|31
|Red foreground
| 
| 
|√
| 
|√
| 

|32
|Green foreground
| 
| 
|√
| 
|√
| 

|33
|Yellow foreground
| 
| 
|√
| 
|√
| 

|34
|Blue foreground
| 
| 
|√
| 
|√
| 

|35
|Magenta foreground
| 
| 
|√
| 
|√
| 

|36
|Cyan foreground
| 
| 
|√
| 
|√
| 

|37
|White foreground
| 
| 
|√
| 
|√
| 

|38
|Extended Foreground (see notes)
| 
| 
| 
| 
|√
| 

|39
|Default foreground (same as white)
| 
| 
|√
| 
|√
| 

|40
|Black background
| 
| 
| 
|√
| 
|√

|41
|Red background
| 
| 
| 
|√
| 
|√

|42
|Green background
| 
| 
| 
|√
| 
|√

|43
|Yellow background
| 
| 
| 
|√
| 
|√

|44
|Blue background
| 
| 
| 
|√
| 
|√

|45
|Magenta background
| 
| 
| 
|√
| 
|√

|46
|Cyan background
| 
| 
| 
|√
| 
|√

|47
|White background
| 
| 
| 
|√
| 
|√

|48
|Extended Background (see notes)
| 
| 
| 
| 
| 
|√

|49
|Default background (same as black)
| 
| 
| 
|√
| 
|√

|91
|Bright Red foreground
| 
|√
|√
| 
|√
| 

|92
|Bright Green foreground
| 
|√
|√
| 
|√
| 

|93
|Bright Yellow foreground
| 
|√
|√
| 
|√
| 

|94
|Bright Blue foreground
| 
|√
|√
| 
|√
| 

|95
|Bright Magenta foreground
| 
|√
|√
| 
|√
| 

|96
|Bright Cyan foreground
| 
|√
|√
| 
|√
| 

|97
|Bright White foreground
| 
|√
|√
| 
|√
| 

|100
|Bright Black background
|√
| 
| 
|√
| 
|√

|101
|Bright Red background
|√
| 
| 
|√
| 
|√

|102
|Bright Green background
|√
| 
| 
|√
| 
|√

|103
|Bright Yellow background
|√
| 
| 
|√
| 
|√

|104
|Bright Blue background
|√
| 
| 
|√
| 
|√

|105
|Bright Magenta background
|√
| 
| 
|√
| 
|√

|106
|Bright Cyan background
|√
| 
| 
|√
| 
|√

|107
|Bright White background
|√
| 
| 
|√
| 
|√

|===

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 (i.e., DECSET mode 32 is not set, which is the default).

NOTE: For 100-107, there is no effect unless bright background colours
are enabled via DECSET mode 33.

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.  <<colors256,[256colors]>>

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 132x60 screen to have unique foreground and background colours
though, so the current screen should always be as expected.

SOURCE: <<ECMA-48>>, <<XTerm>>

=== `CSI Ps n` Device Status Report (`DSR`)
Defaults: `Ps` = 0 +
A request for a status report.  CTerm handles the following three
requests:
[%autowidth,cols="1,2"]
|===
|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.  When origin mode (`CSI ? 6 h`) is enabled,
the reported position is relative to the scroll region, not
the screen.  When the Last Column Flag is set, the reported
column is the last column (not last column + 1).

|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.
|===

SOURCE: <<ECMA-48>> (parameters 5 and 6 only) <<BANSI>> (parameter 255)

=== `CSI = Ps n` State/Mode Request/Report (`CTSMRR`)
NON-STANDARD EXTENSION +
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`
`pF` is the first available loadable-font slot number
`pR` is the result of the previous "Font Selection" request:
[%autowidth,cols="1,2"]
|===
|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:
[%autowidth,cols="1,2"]
|===
|`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.

When `Ps` is 6, CTerm will respond with a Mode Report of the form
`CSI = 6 ; pA n`
Where `pA` is 1 if OSC 8 hyperlink support is available, and 0 if
it is not.

=== `CSI ? Ps [ ; Pn ] n` Device Status Report (`DECDSR`)
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.

SOURCE: <<VT420>>

=== `CSI Ps SP q` Set Cursor Style (`DECSCUSR`)
Defaults: `Ps` = 1
Sets the cursor style

[%autowidth]
|===
|Ps|Result

|0
|Blinking block

|1
|Blinking block

|2
|Steady block

|3
|Blinking underline

|4
|Steady underline

|===

SOURCE: <<VT520>>

=== `CSI Pn1 ; Pn2 r` Set Top and Bottom Margins (`DECSTBM`)
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.

SOURCE: <<VT100>>

=== `CSI Ps1 ; Ps2 * r` Select Communication Speed (`DECSCS`)
Set the output emulation 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:

[%autowidth]
|===
|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
|===

SOURCE: <<VT420>>

=== `CSI ? Ps... s` Save Mode Setting (`CTSMS`)
NON-STANDARD EXTENSION +
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`/`h`).

=== `CSI Pn1 ; Pn2 s` Set Left and Right Margins (`DECSLRM`)
(Only when DEC Left Right Margin Mode  - 69 - is enabled)

Defaults: `Pn1` = 1  `Pn2` = last column on screen +
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.

SOURCE: <<XTerm>>

=== `CSI s` Save Current Position (`SCOSC`)
(Only when DEC Left Right Margin Mode  - 69 - is disabled)
NON-STANDARD EXTENSION
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.

SOURCE: <<ANSISYS>>

=== `CSI Ps ; Pn1 ; Pn2 ; Pn3 t` Select a 24-bit colour (`CT24BC`)
NON-STANDARD EXTENSION

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 132x60 screen to have unique foreground
and background colours though, so the current screen should always
be as expected.

=== `CSI ? Ps...  u` Restore Mode Setting (`CTRMS`)
NON-STANDARD EXTENSION

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`)

=== `CSI u` Restore Cursor Position (`SCORC`)
Move the cursor to the last position saved by `CSI s`.  If no position
has been saved, the cursor is not moved.

SOURCE: <<ANSISYS>>

=== `CSI 2 $ w` Request Tab Stop Report (`DECTABSR`)
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 `/`s.

SOURCE: <<VT320>>

=== `CSI Pn1 ; Ps ; Pn2 ; Pn3 ; Pn4 ; Pn5 * y` Request Checksum of Rectangular Area (`DECRQCRA`)
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.

Source: <<VT420>>

=== `CSI Pn * z` Invoke Macro (`DECINVM`)
Invokes a macro.
`Pn` specifies the macro number.  If `Pn` is not 0..63, no action is
taken.

SOURCE: <<VT420>>

=== `CSI = Ps1 ; Ps2 {` (`CTOSF`)
NON-STANDARD EXTENSION (Deprecated) +
Defaults:  `Ps1` = 255  `Ps2` = 0 +
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:

[%autowidth,cols="1,2"]
|===
|0
|8x16 font, 4096 bytes.

|1
|8x14 font, 3584 bytes.

|2
|8x8 font, 2048 bytes.
|===

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

== Device Control Strings

A Device Control String Begins with a `DCS` and ends with a `ST`
The following commands are supported:

=== `DCS CTerm:Font:p1:<b64> ST` CTerm Loadable Font (`CTLF`)
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 {`

=== `DCS [ p1 [ ; p2 ] ] q ST` Sixel Sequence
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

.Supported Values of `p1`
[%autowidth]
|===
|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
range 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
[%autowidth]
|===
|Function |Parameters |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.
|===

SOURCE: <<VT330340,[VT330/340]>>

=== `DCS $ q pt ST` Request Status String (`DECRQSS`)
`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 pt:
[%autowidth]
|===
|`pt` |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
|===

SOURCE: <<VT420>>

=== `DCS p1 [ ; p2 [ ; p3 ] ! z ST` Define Macro (`DECDMAC`)
Defaults: `p2` = 0  `p3` = 0

Sets a macro to be replayed using `CSI Pn * z`

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

If `p2` is zero, the macro numbered `p1` will be deleted before the new
macro is set. If `p2` is one, all macros are deleted before the new
macro is set.  If the macro is zero length, only the delete action is
stored, you can't store a zero-length macro.

If `p3` is zero, the macro is defined using ASCII characters
(0x20 - 0x7e and 0xa0 - 0xff only).  Note that since ESC (0x1b)
is not in this range, ASCII-mode macros cannot contain escape
sequences; use hex-mode (`p3` = 1) instead.
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.

SOURCE: <<VT420>>

== Operating System Commands

An Operating System Command Begins with an `OSC` and ends with a `ST`
The following commands are supported:

=== `OSC 4;(pX;pY)... ST` Palette Redefinition (`OSC 4`)
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.

SOURCE: <<XTerm>>

=== `OSC 104 [ ; Ps ... ] ST` Reset Palette Entry (`OSC 104`)
Resets palette entry to default.  If the entire string
is "104" (ie: no `Ps` present), resets all colours.  Otherwise, only each index
separated by a semicolon is reset.
SOURCE: <<XTerm>>

=== `OSC 10 ; ? ST` Query Default Foreground Color (`OSC 10`)
Queries the default foreground color. +
CTerm responds with `OSC 10;rgb:RR/GG/BB ST` where `RR`, `GG`, and `BB`
are two hex digit color values.

SOURCE: <<XTerm>>

=== `OSC 11 ; ? ST` Query Default Background Color (`OSC 11`)
Queries the default background color. +
CTerm responds with `OSC 11;rgb:RR/GG/BB ST` where `RR`, `GG`, and `BB`
are two hex digit color values.

SOURCE: <<XTerm>>

=== `OSC 8 ; params ; uri ST` Hyperlink (`OSC 8`)
Sets a hyperlink on subsequent text output. Text printed after this
sequence will be associated with the given URI. An empty URI ends the
hyperlink region.

The `params` field is a colon-separated list of `key=value` pairs.
The `id=` parameter allows non-contiguous text runs to share the same
hyperlink.

Only `http`, `https`, `ftp`, and `ftps` URIs are supported. Other
schemes are silently ignored.

Users can open hyperlinks by clicking when BBS mouse capture is off,
or by Ctrl+clicking when mouse capture is active.

.Examples
----
ESC ] 8 ; ; https://example.com ST Click here ESC ] 8 ; ; ST
ESC ] 8 ; id=link1 ; https://example.com ST part1 ESC ] 8 ; ; ST ... ESC ] 8 ; id=link1 ; https://example.com ST part2 ESC ] 8 ; ; ST
----

SOURCE: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

== Application Program Commands

An Application Program Command begins with an `APC` and ends with a `ST`
SyncTERM implements the following APC commands:

=== `APC SyncTERM:VER ST` Get SyncTERM Version (`CTSV`)
SyncTERM responds with
an `APC` string of the form `APC SyncTERM:VER;version ST` where
`version` is the full version string of SyncTERM, either
`SyncTERM 1.7rc1` for release builds or `SyncTERM 1.7b Debug (Sep 27 2025)`
for debug builds

=== `APC SyncTERM:C;S Ps1 Ps2 ST` Store file (`CTSFI`)
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.

=== `APC SyncTERM:C;L [ ; Ps] ST` List Files (`CTLFI`)
Defaults: `Ps` = * +
`Ps` is the glob(3) pattern to use matching files. +
SyncTERM responds with
an `APC` 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")

=== `APC SyncTERM:C;SetFont; Pn ; Ps ST` Set Font (`CTSF`)
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.

=== `APC SyncTERM:C;DrawPPM Ps... Ps1 ST` Draw a PPM from Cache (`CTDPFC`)
Draws a PPM from the cache directory on the screen. +
`Ps1` is the filename and is required.  Arguments for
`Ps` are optional.  The following options can be included
(separated by semi-colons):

.Currently Supported Ps Arguments:
[%autowidth]
|===
|Argument |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.

=== `APC SyncTERM:C;DrawJXL Ps... Ps1 ST` Draw a JPEG XL from Cache (`CTDJFC`)
Draws a JPEG XL from the cache directory on the screen. +
`Ps1` is the filename and is required.  Arguments for
`Ps` are optional.  The following options can be included
(separated by semi-colons):

.Currently Supported Ps Arguments:
[%autowidth]
|===
|Argument |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.
|===

=== `APC SyncTERM:C;LoadPPM Ps... Ps0 ST` Load a PPM to Buffer (`CTLPTB`)
Loads a PPM to a buffer.  Ps0 is the filename +

.Currently Supported Ps Arguments:
[%autowidth]
|===
|Argument |Description
|`B=#`
|Selects the buffer (0 or 1 only) to paste from.
|===

=== `APC SyncTERM:C;LoadJXL Ps... Ps0 ST` Load a JPEG XL to Buffer (`CTLJTB`)
Loads a JPEG XL to a buffer.  Ps0 is the filename

.Currently Supported Ps Arguments:
[%autowidth]
|===
|Argument |Description
|`B=#`
|Selects the buffer (0 or 1 only) to paste from.
|===

=== `APC SyncTERM:C;LoadPBM Ps... Ps0 ST` Load a PBM to Buffer (`CTLPBTB`)
Loads a PBM to a buffer.  Ps0 is the filename

=== `APC SyncTERM:P;Copy Ps... ST` Copy Screen into Buffer (`CTCSIB`)
Copies a portion of the screen into an internal pixel buffer for use with the
Paste function.  Defaults to copying the entire screen.  All coordinates
and dimensions are in pixels.

.Currently Supported Ps Arguments:
[%autowidth]
|===
|Argument |Description
|`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.
|===

=== `APC SyncTERM:P;Paste Ps... ST` Paste Buffer to Screen (`CTPBTS`)
Pastes from the copied pixel buffer.  Supports the same options as the Cache
DrawPPM command except for the filename, and adds the B= option.
All coordinates and dimensions are in pixels.

.Currently Supported Ps Arguments:
[%autowidth]
|===
|Argument |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.

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

=== `APC SyncTERM:Q;JXL ST` Query JXL Support (`CTQJS`)
Queries support for the JXL image format. +
SyncTERM will respond with a CTerm APC State Report of the form

`CSI = 1 ; pR - n`

pR is 0 if JXL support is not available, and 1 if it is.

== "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:
+
[%autowidth, cols="1,2"]
|===
|`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, or 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
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 1/4 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 1/4 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".

NMOTE: If you are playing some ANSI Music then ask the user if they
heard it, ALWAYS follow it with an 0x0f 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.

== Sequences sent by SyncTERM
The following keys in SyncTERM result in the specified sequence being
sent to the remote.  This is not part of CTerm, but are documented here
for people who want to maintain compatibility.

[%autowidth,cols="1,2"]
|===
|Left Arrow
|"\033[D"

|Right Arrow
|"\033[C"

|Up Arrow
|"\033[A"

|Down Arrow
|"\033[B"

|Home
|"\033[H"

|End
|"\033[K"

|Select
|"\033[K" (Same as End due to termcap weirdness)

|Backspace
|"\b" when DECBKM is set (default), "\x7f" when reset

|Delete
|"\x7f" when DECBKM is set (default), "\033[3~" when reset

|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"
|===

== References

* [[STD-070]]https://vt100.net/manx/details/1,35074[[STD-070\]] Digital Equipment Corporation. Video Systems Reference Manual. 1989-04-14.
* [[ECMA-48]]https://www.ecma-international.org/wp-content/uploads/ECMA-48_5th_edition_june_1991.pdf[[ECMA-48\]] ECMA. Control Functions for Coded Character Sets. June 1991
* [[XTerm]]https://invisible-island.net/xterm/ctlseqs/ctlseqs.pdf[[XTerm\]] Edward May. XTerm Control Sequences. University of California, Berkeley. 2024/09/19
* [[Paste64]]https://invisible-island.net/xterm/xterm-paste64.html[[Paste64\]] Thomas E. Dickey. XTerm -- bracketed paste. 2022
* [[BANSI]]http://www.bbsdocumentary.com/library/PROGRAMS/GRAPHICS/ANSI/bansi.txt[[BANSI\]] Paul Wheaton. BANSI.TXT. 1999
* [[VT102]]https://vt100.net/docs/vt102-ug/[[VT102\]] Digital. VT102 Video Terminal User Guide. 1982.
* [[VT330340]]https://vt100.net/docs/vt3xx-gp/[[VT330/340\]] Digital. VT330/VT340 Programmer Reference Manual, Volume 2: Graphics Programming. May 1988.
* [[VT320]]https://vt100.net/docs/vt320-uu/[[VT320\]] Digital. Installing and Using the VT320 Video Terminal. June 1987.
* [[colors256]]https://jonasjacek.github.io/colors/[[256colors\]] Jonas Jarad Jacek. 256 colors cheat sheet. 2023-12-24.
* [[VT420]]https://vt100.net/docs/vt420-uu/[[VT420\]] Digital. Installing and Using the VT420 Video Terminal. June 1990.
* [[ANSISYS]]https://en.wikipedia.org/wiki/ANSI.SYS[[ANSISYS\]] Wikipedia. ANSI.SYS.
* [[ECMA-35]]https://ecma-international.org/wp-content/uploads/ECMA-35_6th_edition_december_1994.pdf[[ECMA-35\]] ECMA. Character Code Structure and Extension Techniques. December 1994
* [[VT520]]https://vt100.net/dec/ek-vt520-rm.pdf[[VT520\]] Digital. VT520/VT525 Video Terminal Programmer Information. July 1994.
* [[VT100]]https://vt100.net/docs/vt100-ug/contents.html[[VT100\]] Digital. User Guide VT100. 1981.
