How can I convert COLS and ROWS To pixel values in Electron JS?

I have this code on GitHub

and on the line 23rd of main.js, I have this code:

var ptyProcess = pty.spawn(shell, [], {
    name: "xterm-color",
    cols: 80,
    rows: 30,
    cwd: process.env.HOME,
    env: process.env
});

here i have defined the rows and cols of my terminal, but is there any way so that i can convert, cols and rows to pixels?

I want to use the number of Cols and Rows so that i can set the window size of my electron window to same as the number of Rows and Cols of the ptyProcess