====== Attribute (Ctrl-A) Codes ======
//Attribute Codes// (a.k.a. ^A codes) are terminal control sequences embedded in Synchronet text and menu display files.

===== Background =====
Ctrl-A codes are primarily used in place of ANSI X3.64 terminal escape sequences to control terminal text attribute (e.g. color) combinations and perform some cursor positioning and other advanced features (not available with ANSI escape sequences).

The advantage that Ctrl-A codes have over ANSI escape sequences is that they are easily stripped out or converted by the [[:server:terminal|Terminal Server]] of the BBS software to automatically meet the capabilities of the remote user's terminal. There are additional capabilities in Ctrl-A codes that go beyond the realm of terminal control and ANSI escape sequences.

The Ctrl-A character was chosen because it's a control character not often found in displayable text files or expected to be rendered in a consistent manner on all terminals. And "A" is for "Attribute". :-)

Ctrl-A codes may be included in most text files displayed to users of the Synchronet [[server:terminal|Terminal Server]] as well as messages posted in message bases, extended file descriptions, and other places where some colored text can give users the opportunity to better express themselves.

===== Use =====
Ctrl-A codes are 2-character sequences that begin with a Ctrl-A (ASCII 1) character (hence the name) followed by a single character (the operand) which determines the operation to be performed. The only exception to this 2-character sequence is the Ctrl-A''"//filename//'' code, which takes a filename as an argument and the filename is considered part of the sequence and not displayed.

It can sometimes require a special purpose text editor to actually enter a Ctrl-A character into a text file. Some editors may require a special key sequence or use of a menu option to enter an actual Ctrl-A character into a file. The graphical representation of the character may be a happy face (☺) or any other non-alphanumeric symbol that the editor chooses to render to represent that character code. There are [[atcodes|@-Codes]] for the equivalent of most Ctrl-A codes, so consider using them if they are more convenient for your text editor of choice.

In the ''[[custom:text.dat]]'' and possibly some other files (e.g. [[JavaScript]] and [[:util:Baja]] source files), Ctrl-A characters may be included by using the escape sequence ''\1'' (or ''\x01'') rather than having to insert the actual control character into the file.

The [[util:ANS2ASC]] utility may be used to convert files encoded with ANSI X3.64 terminal escape sequences (e.g. ''*.ans'') into Ctrl-A encoded output and the [[util:ASC2ANS]] utility can be used to perform the opposite operation (useful for editing Ctrl-A encoded files (e.g. ''*.msg'' or ''*.asc'') with an //[[resource:ansi editors|ANSI-BBS screen editor]]//).

===== Colors =====

The following table is a list of //Color Control// Ctrl-A codes and their purpose:

^Color	^Foreground^Background^
|Black  |   ''K''  |   ''0''  |
|Red    |   ''R''  |   ''1''  |
|Green  |   ''G''  |   ''2''  |
|Yellow/Brown |   ''Y''  |   ''3''  |
|Blue   |   ''B''  |   ''4''  |
|Magenta|   ''M''  |   ''5''  |
|Cyan   |   ''C''  |   ''6''  |
|White/Gray  |   ''W''  |   ''7''  |

===== Attributes =====

The following table is a list of //Attribute Control// Ctrl-A codes, and a brief description of each code's usage:

^Attribute ^ Code    ^Description                    ^
|Bright            |  ''H''  |High Intensity foreground |
|Blink             |  ''I''  |Blinking (slow), when supported by the terminal |
|Bright-Background |  ''E''  |High intensity background (so-called iCE colors), when supported by the terminal (new in v3.17c) |
|Blink-Font        |  ''f''  |Set the //Blink// attribute **only** if a alternate [[config:fonts.ini|Blink-font]] has been activated in the terminal (new in v3.17) |
|High-Blink-Font   |  ''F''  |Set the //Blink// attribute **only** if a alternate [[config:fonts.ini|High-intensity Blink-font]] has been activated in the terminal (new in v3.17) |
|Normal            |  ''N''  |No Special Attributes (Normal, e.g. light-gray) - resets both //High// and //Blink// attributes |
|Optimized Normal  |  ''-''  |Only changes to //normal// if High Intensity, Blinking, or Background attribute is set (or pop attributes if pushed)|
|Optimized Normal  |  ''_''  |Only changes to //normal// if the Blinking or Background attribute is set |

==== High Intensity and Blink ====
The //High Intensity// console attribute behaves as it does with ANSI terminals: that is, once enabled, the current color and any subsequent new colors will be rendered in their "high intensity" (bright) version. To revert to normal/dark colors, a //Normal// (or //Optimized Normal//) Ctrl-A code must be specified. The //Normal// attribute code will reset both the //High Intensity// and the current color - back to the default, "light gray".

The //Blink// console attribute behaves similarly: once set, all newly-printed characters will have the blink attribute until a //Normal// attribute code is encountered.
===== Control =====

The following table is a list of //Terminal Control// Ctrl-A codes, and a brief description of each code's usage:

^ Operation     ^   Code   ^ Description                    ^
|Pause          |  ''P''   |Display a Pause (e.g. [Hit a key]) Prompt|
|Pause Reset    |  ''Q''   |Reset the line counter for the auto screen-pause function|
|Delay          |  '',''   |Delay for one tenth of a second|
|Delay          |  '';''   |Delay for one half second|
|Delay          |  ''.''   |Delay for two seconds|
|Cls            |  ''L''   |Clear the screen, clear any existing mouse hot-spots, and home the cursor |
|Home           |  '''''   |Home the cursor (without necessarily clearing the screen, used to be ''`'')|
|Hungry-hotspot |  ''~''   |Precedes a single-character hungry mouse hot-spot command (CR if next character is a ctrl char or end of string) |
|Strict-hotspot |  ''`''   |Precedes a single-character strict mouse hot-spot command (or "Home" if next character is a ctrl char or end of string) |
|Clreos         |  ''J''   |Clear to end of screen (leave cursor in current position)|
|Clreol         |  ''>''   |Clear to end of line (leave cursor in current position)|
|Bckspc         |  ''<''   |Send a non-destructive backspace character (Ctrl-H) - Cursor Left|
|CR             |  ''[''   |Send a carriage return character (Ctrl-M) - Cursor to Beginning of Line|
|LF             |  '']''   |Send a line feed character (Ctrl-J) - Cursor Down|
|Cond-Newline   |  ''/''   |Send a new-line sequence (CRLF) **only** when the cursor is not already in the first column (new in v3.17) |
|Cond-Linecont  |  ''\''   |Send a line-continuation sequence (''[[custom:text.dat]]'' //LongLineContinuationPrefix// line) if terminal < 80 columns |
|Cond-Blankline |  ''?''   |Send a blank-line sequence **only** when the previously printed line was not blank (new in v3.17) |
|Push Attr      |  ''+''   |Save current attributes into (server-side) attribute LIFO stack|
|Pop Attr       |  ''-''   |Restore attributes from stack (or Optimized Normal, if no attributes saved/pushed)|
|SOH            |  ''A''   |Send an actual Ctrl-A (ASCII 1) character|
|SUB            |  ''z''   |Send an actual Ctrl-Z (ASCII 26) character (note: lowercase 'z' only v3.17c and later) |
|EOF            |  ''Z''   |Premature end-of-file (note: uppercase 'Z' only in v3.17c and later) |
|Cursor Right   |  128-255 |Move cursor to the right (code-127) characters|

===== Macros ===== 

The following table is a list of //Macro// Ctrl-A codes, and a brief description of each code's usage:

^Macro    ^ Code    ^Description                    ^
|Date     |  ''D''  |Display the current system date (in "MM/DD/YY" or "DD/MM/YY" format)|
|Time     |  ''T''  |Display the current system time (in "HH:MM am" or "HH:MM:SS" format)|

===== Advanced ===== 

The following table is a list of //Advanced// Ctrl-A codes, and a brief description of each code's usage:

^Operation^ Code    ^Description                          ^
|Sync     |  ''S''  |Synchronize node status and output with terminal (i.e. initiates a call to ''nodesync()'')|
|Embed File| ''%%"%%//filename//''| Display contents of //filename// from the Terminal Server's ''[[dir:text]]'' directory|

===== Security =====

Synchronet also supports //Secure Control// Ctrl-A codes which may be used to hide text from users
not meeting certain security criteria (i.e.: Security Level or Flags from Flag Set #1).

The following table is a list of Security Control Ctrl-A codes, and a brief description of each code's usage:

^Code		   ^Description^
|Ctrl-A thru Ctrl-Z|Only display the following text to users with the corresponding flag A through Z turned on (from Flag Set #1)|
|''!''|Toggle the text display off/on for users of less than level 10|
|''@''|Toggle the text display off/on for users of less than level 20|
|''#''|Toggle the text display off/on for users of less than level 30|
|''$''|Toggle the text display off/on for users of less than level 40|
|''%''|Toggle the text display off/on for users of less than level 50|
|''^''|Toggle the text display off/on for users of less than level 60|
|''&''|Toggle the text display off/on for users of less than level 70|
|''*''|Toggle the text display off/on for users of less than level 80|
|''(''|Toggle the text display off/on for users of less than level 90|
|'')''|Restore the displaying of text to ALL users|


===== See Also =====
  * [[atcodes|@-Codes]]
  * [[:util:ANS2ASC]] 
  * [[:util:ASC2ANS]]
  * [[:ref:ANSI]]
  * [[:custom:|Customization]]
  * [[:resource:ANSI Editors]]

{{tag>ansi}}