gistfile1.txt

<?php
//content type
header('Content-Type: image/png');

$font = 'znikomit-webfont.ttf';
$font_size = $_GET['s'];
$width = $_GET['w'];
$margin = 5;
 
$text = $_GET['t'];
 
//explode text by words
$text_a = explode(' ', $text);
$text_new = '';
foreach($text_a as $word){
    //Create a new text, add the word, and calculate the parameters of the text
    $box = imagettfbbox($font_size, 0, $font, $text_new.' '.$word);
    //if the line fits to the specified width, then add the word with a space, if not then add word with new line
    if($box[2] > $width - $margin*2){
        $text_new .= "\n".$word;
    } else {
        $text_new .= " ".$word;
    }
}

//trip spaces
$text_new = trim($text_new);

//new text box parameters
$box = imagettfbbox($font_size, 0, $font, $text_new);

//new text height
$height = $box[1] + $font_size + $margin * 2;
 
//create image
$im = imagecreatetruecolor($width, $height);
 
//create colors
$white = imagecolorallocate($im, 255, 255, 255);
$black = imagecolorallocate($im, 0, 0, 0);

//color image
imagefilledrectangle($im, 0, 0, $width, $height, $white);
 
//add text to image
imagettftext($im, $font_size, 0, $margin, $font_size+$margin, $black, $font, $text_new);
 
//return image
imagepng($im);
//frees any memory associated with image
imagedestroy($im);