Some control sequences are not rendered properly

[zolem]

I am not an expert in parsing out ansi control sequences but I did notice there were a few that seemed to just pop up as the missing character.

Here is a screenshot of what I am talking about

At the moment I am testing with some logged data from the server that I have pasted below:

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�[1m�[31m   \_/\_/ \___|_|\___\___/|_| |_| |_|\___|
�[1m�[35m ****     ****                         �[1m�[31m| |_ ___ �[1m�[35m**   **
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�[0;37;40m�[34m//         //  ////// ///    ////// ///   //    //  //   //  ////////

�[1m�[37m           Driver: MudOS v22.1b23    Mudlib: Merentha/NM MM-2.03 
�[1m�[37m     <<<  Visit the Merentha web page at http://www.merentha.com  >>>
		�[1m�[37mThere are currently 15 adventurers playing

�[0;37;40m�[32mWhat name do you wish?�[0;37;40m 

    �[1m�[32m*-=-=-=-=-=-=-=-=-=-=-=-| �[35mWelcome Back�[32m |-=-=-=-=-=-=-=-=-=-=-=-*
    | �[35mA character by the name Zolem has already been               �[32m|
    | �[35mcreated in Merentha.                                         �[32m|
    |                                                              �[32m|
    | �[35mIf this is not your character disconnect and reconnect with  �[32m|
    | �[35ma new name.  You can disconnect by hitting <enter> at the    �[32m|
    | �[35mpassword prompt without entering a password.                 �[32m|
    *-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=*

�[0;37;40m�[32mWelcome Back!
Please enter your password: ���
��� 
�[0;37;40m        >>> Terminal currently set to ansi <<<
�[0;37;40m�[0;37;40m�[32m*=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-| �[1m�[35mNews �[0;37;40m�[32m|=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-*
�[1m�[33m  THE RULES:

Details

• Electron:
• Windows 10:
• xterm.js 3.1:

[Tyriar]

You can see what's being sent to xterm.js by turning on debug mode:

term.setOption('debug', true);

This will output what's happening to the console. If you can narrow down the particular parts that are failing we can probably identify the issue.

[zolem]

Thanks for responding. I actually looked through the code and I noticed that the 3 control sequences are on the escape sequences file but i didnt see them actually being used anywhere. Im on my phone at the moment but if I recall they are SOH, US, and CAN. There are some other characters in between but idk what those are. I would offer to do a pull request if someone has a reference to what those are supposed to do. I know CAN is cancel, but I dont know how xterm is supposed to interpret that. Does it just delete the entire line just preceding characters? When I get that same data on actual xterm the entire first line just doesnt render.

[Tyriar]

SOH, US and CAN don't seem to be in this document which I essentially treat as a spec http://invisible-island.net/xterm/ctlseqs/ctlseqs.html

Also I'm not sure what this escape sequences file to which you are referring. Did you see the output generated by debug mode xterm.js just before the ascii welcome is printed?

[zolem]

Here are the lines of code I am refering to:

xterm.js/src/EscapeSequences.ts

Line 14 in adcbb1a

export const SOH = '\x01';

xterm.js/src/EscapeSequences.ts

Line 74 in adcbb1a

export const US = '\x1f';

Looks like CAN is used by the parser so I am not sure why it doesn't do whatever it is supposed to do. Or maybe it is and there are just other characters with problems.

xterm.js/src/EscapeSequences.ts

Line 60 in adcbb1a

export const CAN = '\x18';

xterm.js/src/Parser.ts

Line 79 in adcbb1a

escapedStateHandler[C0.CAN] = (parser) => parser.setState(ParserState.NORMAL);

xterm.js/src/Parser.ts

Line 100 in adcbb1a

csiParamStateHandler[C0.CAN] = (parser) => parser.setState(ParserState.NORMAL);

xterm.js/src/Parser.ts

Line 151 in adcbb1a

csiStateHandler[C0.CAN] = (handler, params, prefix, postfix, parser) => parser.setState(ParserState.NORMAL);

When I run debug and only push the lines in question it just returns the line and then undefined.

NP++ shows the lines like this:

[Tyriar]

For the password but there are 2 characters followed by SOH. Those 2 characters appear to be getting renderers, I kind of expect this? Does this happen with other terminals?

[zolem]

In the new windows bash if I connect to the game there are no weird characters at all. Clearly everything is being interpreted to do something.

[Tyriar]

This is likely the root cause of #1461, let's close it in favor of that for easier tracking.