Intracto IO animation

io.php

#!/usr/bin/env php
<?php

require __DIR__.'/vendor/autoload.php';

use Symfony\Component\Console\Cursor;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\SingleCommandApplication;
use Symfony\Component\Console\Terminal;

define('LOGOS', 50);
define('SPEED', 250000);

(new SingleCommandApplication())
    ->setCode(function (InputInterface $input, OutputInterface $output) {
        $terminal = new Terminal();
        $width = $terminal->getWidth();
        $height = $terminal->getHeight();
        $cursor = new Cursor($output);
        $cursor->hide();
        $cursor->clearScreen();

        $logos = [];

        while (true) {
            // smoother startup
            for ($i = round((LOGOS - count($logos)) * 0.3); $i > 0; $i--) {
                $logos[] = new IOLogo(
                    $output,
                    $cursor,
                    rand(0, $width - 16),
                    rand(0, $height - 5)
                );
            }

            foreach ($logos as $i => $logo) {
                $logo->animate();
                if (! $logo->visible()) {
                    unset($logos[$i]);
                }
            }

            usleep(SPEED);
        }

        return 0;
    })->run();

class IOLogo
{
    private OutputInterface $output;
    private Cursor $cursor;

    private int $x;
    private int $y;

    private array $fg;
    private array $bg;

    public function __construct(OutputInterface $output, Cursor $cursor, int $x, int $y)
    {
        $this->output = $output;
        $this->cursor = $cursor;

        $this->x = $x;
        $this->y = $y;

        $this->fg = [ rand(0, 127), rand(0, 127), rand(0, 127) ];
        $this->bg = [
            min([255, $this->fg[0]+128]),
            min([255, $this->fg[1]+128]),
            min([255, $this->fg[2]+128])
        ];
    }

    public function animate(): void
    {
        $this->fade();

        $this->write(0, " ,--.  ,-----.  ");
        $this->write(1, " |  | '  .-.  ' ");
        $this->write(2, " |  | |  | |  | ");
        $this->write(3, " '  | '  '-'  ' ");
        $this->write(4, "  `-'  `-----'  ");
    }

    public function visible(): bool
    {
        return 255*6 >
            $this->fg[0]+$this->fg[1]+$this->fg[2]+
            $this->bg[0]+$this->bg[1]+$this->bg[2]
        ;
    }

    private function fade(): void
    {
        $this->fg = [
            min([255, $this->fg[0]+20]),
            min([255, $this->fg[1]+20]),
            min([255, $this->fg[2]+20])
        ];
        $this->bg = [
            min([255, $this->bg[0]+20]),
            min([255, $this->bg[1]+20]),
            min([255, $this->bg[2]+20])
        ];
    }

    private function write($line, $txt): void
    {
        $this->cursor->moveToPosition($this->x, $this->y+$line);
        $this->output->write('<fg=#'.$this->hexval($this->fg).';bg=#'.$this->hexval($this->bg).'>'.$txt.'</>');
    }

    private function hexval(array $value): string
    {
        return
            str_pad(dechex($value[0]), 2, '0', STR_PAD_LEFT).
            str_pad(dechex($value[1]), 2, '0', STR_PAD_LEFT).
            str_pad(dechex($value[2]), 2, '0', STR_PAD_LEFT)
        ;
    }
}