Simple captcha php script not displaying text on image - php

Question

I was hoping to get in touch with someone on a situation that I cannot find the solution to anywhere.
I am trying to create a captcha on my website using php and although I was able to create an image and create the random captcha text.
I am unable to over lay the two. Here is my code:
<?PHP
session_start();
function generateRandomString($length = 10) {
$letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
$len = strlen($letters);
$letter = $letters[rand(0, $len - 1)];
$text_color = imagecolorallocate($image, 0, 0, 0);
$word = "";
for ($i = 0; $i < 6; $i++) {
$letter = $letters[rand(0, $len - 1)];
imagestring($image, 7, 5 + ($i * 30), 20, $letter, $text_color);
$word .= $letter;
}
$_SESSION['captcha_string'] = $word;
}
function security_image(){
// $code = isset($_SESSION['captcha']) ? $_SESSION['captcha'] : generate_code();
//$font = 'content/fonts/comic.ttf';
$width = '110';
$height = '20';
$font_size = $height * 0.75;
// $image = #imagecreate($width, $height) or die('GD not installed');
global $image;
$image = imagecreatetruecolor($width, $height) or die("Cannot Initialize new GD image stream");
$background_color = imagecolorallocate($image, 255, 255, 255);
imagefilledrectangle($image,0,0,200,50,$background_color);
$line_color = imagecolorallocate($image, 64,64,64);
for($i=0;$i<10;$i++) {
imageline($image,0,rand()%50,200,rand()%50,$line_color);
}
$pixel_color = imagecolorallocate($image, 0,0,255);
for($i=0;$i<1000;$i++) {
imagesetpixel($image,rand()%200,rand()%50,$pixel_color);
}
//$textbox = imagettfbbox($font_size, 0, $font, $code);
//$textbox = imagettfbbox($font_size, 0, $randomString);
$x = ($width - $textbox[4]) / 2;
$y = ($height - $textbox[5]) / 2;
// imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code);
imagettftext($image, $font_size, 0, $x, $y, $text_color , $word);
$images = glob("*.png");
foreach ($images as $image_to_delete) {
#unlink($image_to_delete);
}
imagepng($image, "image" . $_SESSION['count'] . ".png");
header('Content-Type: image/png');
imagepng($image);
imagedestroy($image);
}
security_image();
?>
I have no idea what I’m doing wrong. I’ve spent over 10 hours on this “display text” issue. I don’t understand and I am desperate for help. I even downloaded working captcha version from other resources that break once I upload it to my server. I have no idea whats going on. At first I thought there was something wrong with my server but the fact that I can even create the pixels, lines image means that it is at least working.
Please help!!!! 
UPDATE---------------------------------------------
Thank you for your suggestions. Here is the edited code. I'm still getting the same issue.
<?PHP
session_start();
function security_image(){
global $image;
// $code = isset($_SESSION['captcha']) ? $_SESSION['captcha'] : generate_code();
$font = 'content/fonts/comic.ttf';
$width = '110';
$height = '20';
$font_size = $height * 0.75;
$image = imagecreatetruecolor($width, $height) or die("Cannot Initialize new GD image stream");
$background_color = imagecolorallocate($image, 255, 255, 255);
imagefilledrectangle($image,0,0,200,50,$background_color);
$line_color = imagecolorallocate($image, 64,64,64);
for($i=0;$i<10;$i++) {
imageline($image,0,rand()%50,200,rand()%50,$line_color);
}
$pixel_color = imagecolorallocate($image, 0,0,255);
for($i=0;$i<1000;$i++) {
imagesetpixel($image,rand()%200,rand()%50,$pixel_color);
}
$letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
$len = strlen($letters);
$letter = $letters[rand(0, $len - 1)];
$text_color = imagecolorallocate($image, 0, 0, 0);
$word = "";
for ($i = 0; $i < 6; $i++) {
$letter = $letters[rand(0, $len - 1)];
imagestring($image, 7, 5 + ($i * 30), 20, $letter, $text_color);
$word .= $letter;
}
$_SESSION['captcha_string'] = $word;
/*texbox unitinitialized (removed for the sake of just showing the word size doesnt matter)
$x = ($width - $textbox[4]) / 2;
$y = ($height - $textbox[5]) / 2;
*/
$x = ($width) / 2;
$y = ($height) / 2;
imagettftext($image,$font, 4, $x, $y, $word);
header('Content-Type: image/png');
imagepng($image);
imagedestroy($image);
}
security_image();?>
i made some suggested changes but the code seems to still do the same thing. Just display the lines and pixels as expected but the text still is missing... ?

Answer 1

There are some several "errors" in your functions, let's fix them:
In generateRandomString()
generateRandomString($length = 10)
$lenght is not used its scope.
$text_color = imagecolorallocate($image, 0, 0, 0);
$image is uninitialized
In security_image() function:
$textbox is uninitialized
$text_color and $word is uninitialized.
And Wrong parameter count for imagettftext() You add 7 parameters, and forget the font file parameter.

Answer 2

found the problem. using this:
http://php.net/manual/en/function.imagettftext.php
i was able to see that the font location was incorrect. using the example on that page and editing it to my needs worked.