<?php

function c1(&$c, $rand) {
    if($c['red'] <= 30 && $c['green'] >= 230 && $c['blue'] >= 220){
        $c['red'] = $rand[0];
        $c['green'] = $rand[1];
        $c['blue'] = $rand[2];
    }
    if($c['red'] <= 30 && $c['green'] >= 230 && $c['blue'] <= 30){
        $c['red'] = $rand[0] * 0.8;
        $c['green'] = $rand[1] * 0.8;
        $c['blue'] = $rand[2] * 0.8;
    }
};


function c2(&$c, $rand) {
    if($c['red'] >= 240 && $c['green'] >= 240 && $c['blue'] <= 10){
        $c['red'] = $rand[0];
        $c['green'] = $rand[1];
        $c['blue'] = $rand[2];
    }
    if($c['red'] >= 240 && $c['green'] <= 10 && $c['blue'] <= 10){
        $c['red'] = $rand[0] * 0.6;
        $c['green'] = $rand[1] * 0.6;
        $c['blue'] = $rand[2] * 0.6;
    }
};


function c3(&$c, $rand) {
    if ($c['red'] <= 30 && $c['green'] >= 230 && $c['blue'] >= 220) {
        $c['red'] = $rand[0];
        $c['green'] = $rand[1];
        $c['blue'] = $rand[2];
    }
    if ($c['red'] <= 30 && $c['green'] >= 230 && $c['blue'] <= 30) {
        $c['red'] = $rand[0] * 0.8;
        $c['green'] = $rand[1] * 0.8;
        $c['blue'] = $rand[2] * 0.8;
    }
    if ($c['red'] >= 240 && $c['green'] >= 240 && $c['blue'] <= 10) {
        $c['red'] = $rand[0] * 0.6;
        $c['green'] = $rand[1] * 0.6;
        $c['blue'] = $rand[2] * 0.6;
    }
    if ($c['red'] >= 240 && $c['green'] <= 10 && $c['blue'] <= 10) {
        $c['red'] = $rand[0] * 0.4;
        $c['green'] = $rand[1] * 0.4;
        $c['blue'] = $rand[2] * 0.4;
    }
};


function getColor(){
    return mt_rand(0,255);
};

function soboken($dir, $user_id){
    $h = 388;
    $w = 344;

    $canvas = imagecreatetruecolor($w,$h);

    $randNum = mt_rand(1,4);
    $img_src = 'img/soboken' . $randNum . '.jpg';

    $id = uniqid($randNum);
    $path = $dir . '/' . $user_id . '.png';

    $image = imagecreatefromjpeg($img_src);

    $rand1 = [getColor(), getColor(), getColor()];
    $rand2 = [getColor(), getColor(), getColor()];

    $i=0;

    for ($y = 0; $y < $h; $y++){
        for($x = 0; $x < $w; $x++){

            if ($i % 5 === 0){
                $irand = mt_rand(0,2);
                $rand1[$irand] = min($rand1[$irand] * 1.00011, 255);
                $rand2[$irand] = min($rand2[$irand] * 1.00011, 255);
            }

            $index = imagecolorat($image, $x,$y);
            $data = imagecolorsforindex($image, $index);

            c1($data, $rand1);
            c2($data, $rand2);
            c3($data, $rand1);

            $color = imagecolorallocatealpha($canvas, $data['red'], $data['green'], $data['blue'], $data['alpha']);
            imagesetpixel($canvas, $x,$y, $color);
            $i++;
        }
    }

    imagepng($canvas,$path,9);

    imagedestroy($canvas);
    imagedestroy($image);

    return $path;
};

echo soboken('../i', 100500); // папка для записи "i", путь к файлу