Add pixel size support to resize()

[anthonykim1]

From: xtermjs/xterm.js#5619 (comment)

[anthonykim1]

Testing the pass through with js script with:

1. npm run build
2. node examples/test-pixel-resize.js

where test-pixe-resize.js

/**

• Test script to verify pixel size is passed to the pty.
• Run with: node examples/test-pixel-resize.js
  */
  import * as os from 'node:os';
  import * as pty from '../lib/index.js';

const isWindows = os.platform() === 'win32';
const shell = isWindows ? 'powershell.exe' : 'bash';

const ptyProcess = pty.spawn(shell, [], {
name: 'xterm-256color',
cols: 80,
rows: 24,
cwd: isWindows ? process.env.USERPROFILE : process.env.HOME,
env: process.env
});

ptyProcess.onData(data => process.stdout.write(data));

// On Unix, we can query the terminal size including pixel dimensions
// using the escape sequence: ESC [ 1 4 t (report window size in pixels)
// or use stty/resize commands, or write a small C program

if (!isWindows) {
// Method 1: Use stty size to get rows/cols (doesn't show pixels though)
console.log('\n--- Testing resize with pixel dimensions ---\n');

// Resize with pixel dimensions: 800x600 pixels
ptyProcess.resize(100, 30, { width: 800, height: 600 });
console.log('Resized to 100x30 chars, 800x600 pixels');

// Query window size - this C one-liner reads TIOCGWINSZ and prints all 4 values
ptyProcess.write(python3 -c " import fcntl, termios, struct buf = fcntl.ioctl(0, termios.TIOCGWINSZ, b'\\x00' * 8) rows, cols, xpixel, ypixel = struct.unpack('HHHH', buf) print(f'rows={rows}, cols={cols}, xpixel={xpixel}, ypixel={ypixel}') "\r);
}

setTimeout(() => {
ptyProcess.kill();
process.exit(0);
}, 3000);

(Done) TODO before merging:
Now I should test if this works when I symlink node-pty on xterm

Edit: See result below!

[anthonykim1]

Symlinked my local node-pty to test on xterm demo:

🤩🚀

[jerch]

@anthonykim1 Gonna add the ioctl's for TIOCGWINSZ/TIOCSWINSZ to the node-termios package, then you don't have to shim it with your own C helper.

[Tyriar]

@jerch we don't use that atm though and want to avoid including dev dependencies in general?

[jerch]

@Tyriar No need to include into the automated CI testing. It is more helpful for exploring local tests as @anthonykim1 did above and would spare the need to go into C yourself (so it would help any JS/TS dev without any C experience).

[jerch]

@anthonykim1 The new package is online now: https://www.npmjs.com/package/node-termios/v/0.2.0

With it you can create a console app in nodejs tracking the TTY size like this:

const { native: { tcgetwinsize } } = require('node-termios');

// file descriptor of STDIN
const STDIN_FD = 0;

// needed to keep the process running
// (not needed if you keep the event loop running by other means)
process.stdin.resume();

// register a signal handler for SIGWINCH
process.on('SIGWINCH', () => {
  console.log('TTY size:', tcgetwinsize(STDIN_FD));
});

and then resizing the terminal window. This works only under macos/linux though (prolly also under FreeBSD, Solaris is untested).