$Id: cterm.txt,v 1.79 2020/04/28 19:39:13 deuce Exp $

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.

I'm often asked why I don't use VT semantics for wrapping.
The primary reason is that the person asking almost certainly
doesn't know what the VT semantics are, they just want
SyncTERM to behave the same as some other terminal they like.

Not only have the VT semantics never been properly
implemented in any terminal, they even varied between
different actual hardware VT terminals.  Luckily, everything
is on the internet now, so you can see the details and results
here: https://github.com/mattiase/wraptest

Control characters:

0x00 - 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.

0x07 - BEL:
	Beep

0x08 - 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.

0x09 - 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.

0x0A - 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.

0x0D - CR:
	Move cursor position to column 1 of the current line

Control Codes:
--------------

Control codes are in the following format:
ESC {'0' (ZERO) 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)

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

ESC P	Device Control String (DCS)
	Begins a string consisting of the characters 0x08 - 0x0d and
	0x20-0x7e, terminated by a String Terminator (ST)
	Supported OSC values:
		"CTerm:Font:p1:<b64>"
		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 {


		[ p1 [ ; p2 ] ] q
		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
                ! 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.


		$ q pt
		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 p1:

		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


		p1 [ ; p2 [ ; p3 ] ! z
		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 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.

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.

ESC \	String Terminator (ST)

ESC ]	Operating System Command (OSC)
	Begins a string consisting of the characters 0x08 - 0x0d and
	0x20-0x7e, terminated by a String Terminator (ST)
	Supported OSC values:
		4;(pX;pY)...
		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

		104 [ ; Ps ... ]
		Resets palette entry to default.  If the entire string
		is "104", resets all colours.  Otherwise, only each index
		separated by a semicolon is reset.

		SOURCE: xterm

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.

ESC _	Application Program String (APS)
	Begins a string consisting of the characters 0x08 - 0x0d and
	0x20-0x7e, terminated by a String Terminator (ST)
	The string is currently ignored.

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

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.

	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 @ (ICH)
	Insert Character(s)
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn SP @ (SL)
	Scroll Left
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn A (CUU)
	Cursor Up
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn SP A (SR)
	Scroll Right
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn B (CUD)
	Cursor Down
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn C (CUF)
	Cursor Right
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn D (CUB)
	Cursor Left
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Ps1 ; Ps2 sp D (FNT)
	Font Selection
	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:
		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 (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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn E (CNL)
	Cursor Next Line
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn F (CPL)
	Cursor Preceding Line
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn1 ; Pn2 H (CUP)
	Cursor Position
	Defaults: Pn1 = 1  Pn2 = 1
	Moves the cursor to the Pn2th column of the Pn1th line.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Ps J (ED)
	Erase in Page
	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-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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf
	SOURCE BANSI.TXT

CSI Ps K (EL)
	Erase in Line
	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.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn L (IL)
	Insert Line(s)
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn M (DL)
	Delete Line(s) / "ANSI" Music
	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.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf
	SOURCE: BANSI.TXT

CSI = Ps M (CTSAM)
	CTerm Set ANSI Music
	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.

	SOURCE: CTerm only.

CSI N (BCAM)
	BananaCom ANSI Music
	"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 section for more
	details.

	SOURCE: BANSI.TXT

CSI Pn P (DCH)
	Delete Character
	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.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI ? Ps1 ; Ps2 S (XTSRGA)
	XTerm Set or Request Graphics Attribute
	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 (SD)
	Scroll Down
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI U
	NON-STANDARD (Disabled in current code)
	Clear screen with default attribute.
	This code is *supposed* to go to the "next page" according to the
	ANSI/ECMA specs with CSI V going to "previous page"

	SOURCE: BANSI.TXT

CSI Pn X (ECH)
	Erase Character
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn Z (CBT)
	Cursor Backward Tabulation
	Defaults: Pn = 1
	Move the cursor to the p1th preceding tab stop.  Will not go past the
	start of the line.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn a (HPR)
	Cursor Position Forward
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Ps c (DA)
	Device Attributes
	Defaults: Ps = 0
	If Ps is 0, CTerm will reply with the sequence:
        CSI = 67;84;101;114;109;pN c
	64;84;101;114;109 is the ASCII values of the "CTerm" string.  pN is the
	CVS revision ID of CTerm with dots converted to semi-colons
	(e.g. "1;156").  Use the CVS 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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI < Ps c (CTDA)
	CTerm Device Attributes

	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 - Palette entries may be modified via an Operating System Command
	    string
	3 - Pixel operations are supported (currently, sixel graphics)
	4 - The current font may be selected via CSI Ps1 ; Ps2 sp D
	5 - More than the standard 16 colours may by configured via
	    Operating System Command strings
	6 - Extended palette is available
	7 - Mouse is available

CSI Ps d (VPA)
	Line Position Absolute
	Defaults: Ps = 1
	Moves to row specified by Ps.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn1 ; Pn2 (HVP)
	Character and Line Position
	Defaults: Pn1 = 1  Pn2 = 1
	Moves the cursor to the Pn2th column of the Pn1th line.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Ps g (TBC)
	Tabulation Clear
	Defaults: Pn = 0
	Deletes tab stops according to the values of P1:
	0 - Deletes tab stop at current position.
	3 - Deletes all tab stops.
	5 - Deletes all tab stops.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: BANSI.TXT

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

	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: Digital VT102 User Guide
	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: Digital VT102 User Guide
	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: "Installing and Using the VT320 Video Terminal"
	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.
	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: VT330/VT340 Programmer Reference Manual
	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 change 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

CSI Pn j (HPB)
	Character Position Backward
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

CSI Pn k (VPB)
	Line Position Backward
	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf

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

	SOURCE: BANSI.TXT

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

	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: Digital VT102 User Guide
	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: Digital VT102 User Guide
	9 -  Disable X10 compatible mouse reporting
	25 - Hide the cursor.  Defaults to set.
	     SOURCE: "Installing and Using the VT320 Video Terminal"
	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.
	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: VT330/VT340 Programmer Reference Manual
	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

CSI Ps... m (SGR)
	Select Graphic Rendition
	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:
	                                        Blink Bold FG BG TF TB (Modified)
	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
	     NOTE: Both blinks are the same speed.
	7 -  Negative Image - Reverses FG and BG           X  X  X  X
	8 -  Concealed characters, sets the                X     X  X
	     foreground colour to the background
	     colour.
	22 - Normal intensity                           X        X
	25 - Steady (Not blinking)                 X                X
	27 - Positive Image - Reverses FG and BG           X  X  X  X
	     NOTE: This should be a separate
	           attribute than 7 but this
	           implementation makes them equal
	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     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

	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 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.  See here:
	https://jonasjacek.github.io/colors/

	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: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf
	SOURCE: XTerm

CSI Ps n (DSR)
	Device Status Report
	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.

	SOURCE: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf
		(parameters 5 and 6 only)
	SOURCE: BANSI.TXT (parameter 255)

CSI = Ps n (CTSMRR)
	NON-STANDARD EXTENSION
	State/Mode Request/Report
	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:
		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.

	SOURCE: CTerm only.

CSI ? Ps [ ; Pn ] n (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 Pn1 ; Pn2 r (DECSTBM)
	NON-STANDARD EXTENSION.
	Set Top and Bottom Margins
	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: xterm

CSI Ps1 ; Ps2 * r (DECSCS)
	NON-STANDARD EXTENSION.
	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

	SOURCE: VT4xx Specification from http://www.vt100.net/

CSI ? Ps... s (CTSMS)
	NON-STANDARD EXTENSION
	Save Mode Setting
	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).

	SOURCE: SyncTERM only

CSI Pn1 ; Pn2 s (DECSLRM)
        (Only when DEC Left Right Margin Mode  - 69 - is enabled)
	NON-STANDARD EXTENSION.
	Set Left and Right Margins
	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 (SCOSC)
        (Only when DEC Left Right Margin Mode  - 69 - is disabled)
	NON-STANDARD EXTENSION
	Save Current Position
	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: ANSI.SYS

CSI Ps ; Pn1 ; Pn2 ; Pn3 t (CT24BC)
	NON-STANDARD EXTENSION
	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 132x60 screen to have unique foreground
	and background colours though, so the current screen should always
	be as expected.

CSI ? Ps...  u (CTRMS)
	NON-STANDARD EXTENSION
	Restore Mode Setting
	Saves the current mode states as specified by CSI ? l and CSI ? h.  If
	Ps is omitted, saves all such states.  If one or more values of Ps is
	included, restores all the specified states (arguments to CSI ? l/h)

	SOURCE: SyncTERM only

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

	SOURCE: ANSI.SYS

CSI 2 $ w (DECTABSR)
	Request Tab Stop Report
	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 (DECRQCRA)
	Request Checksum of Rectangular Area
	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 (DECINVM)
	Invoke Macro
	Invokes a macro.
	Pn specifies the macro number.  If Pn is not 0..63, no action is
	taken.

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:
		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

	SOURCE: CTerm only.

"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, 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
	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 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".

!!!PLEASE NOTE!!! 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.
