PHP Random Walk Path

LatticeRandomWalk.php

<?php
class LatticeRandomWalk {
    private int $width;
    private int $height;
    private int $steps;
    private array $color;
    private int $stepLength;

    public function __construct(int $width, int $height, int $steps, int $stepLength = 1, array $color = [0, 0, 0]) {
        $this->width = $width;
        $this->height = $height;
        $this->steps = $steps;
        $this->color = $color;
        $this->stepLength = $stepLength;
    }

    private function isValidMove(int $x, int $y, array &$visited): bool {
        return $x >= 0 && $x < $this->width && $y >= 0 && $y < $this->height && !isset($visited["$x,$y"]);
    }

    public function generateImage(string $filename): void {
        $image = imagecreatetruecolor($this->width, $this->height);
        $backgroundColor = imagecolorallocate($image, 255, 255, 255);
        imagefill($image, 0, 0, $backgroundColor);
        $lineColor = imagecolorallocate($image, $this->color[0], $this->color[1], $this->color[2]);

        // Set the initial x and y coordinates to random values within the image bounds
        $x = rand(0, $this->width - 1);
        $y = rand(0, $this->height - 1);

        $visited = [];
        $visited["$x,$y"] = true;

        for ($i = 0; $i < $this->steps; $i++) {
            $validMove = false;
            $directions = range(0, 3);
            shuffle($directions);

            foreach ($directions as $direction) {
                $newX = $x;
                $newY = $y;
                $intermediatePoints = [];

                for ($j = 0; $j < $this->stepLength; $j++) {
                    switch ($direction) {
                        case 0:
                            $newX++; // Move right
                            break;
                        case 1:
                            $newY++; // Move down
                            break;
                        case 2:
                            $newX--; // Move left
                            break;
                        case 3:
                            $newY--; // Move up
                            break;
                    }

                    if ($this->isValidMove($newX, $newY, $visited)) {
                        $intermediatePoints[] = ["$newX,$newY"];
                    } else {
                        break;
                    }
                }

                if (count($intermediatePoints) === $this->stepLength) {
                    $validMove = true;
                    break;
                }
            }

            if (!$validMove) {
                continue;
            }

            imageline($image, $x, $y, $newX, $newY, $lineColor);

            foreach ($intermediatePoints as $point) {
                #die(print_r($point));
                $visited[implode(',', $point)] = true;
            }

            $x = $newX;
            $y = $newY;
        }

        imagepng($image, $filename);
        imagedestroy($image);
    }
}


$randomWalk = new LatticeRandomWalk(500, 500, 100, 10);
$randomWalk->generateImage('walk.png');