Captcha image is generated but numbers are not generated - php

Question

This is generate.php code:
<?php
ob_start();
session_start();
header('content-type:image/jpeg');
$text=$_SESSION['secure'];
$font_size=30;
$width=100;
$height=40;
$image=imagecreate($width, $height);
imagecolorallocate($image, 0, 0, 0);
$text_color=imagecolorallocate($image, 255, 255, 255);
$font='Consolas.ttf';
for($x=1; $x <= 30; $x++) {
$x1 = rand(1, 100);
$y1 = rand(1, 100);
$x2 = rand(1, 100);
$y2 = rand(1, 100);
imageline($image, $x1, $y1, $x2, $y2, $text);
}
imagettftext($image, $font_size, 0, 15, 30, $text_color, $font, $text);
$imgSrc="out.png";
imagepng($image, $imgSrc);
?>
This is HTML code to display an image, here out.png is successfully generated and loaded into the page but numbers cannot be found.
<div class="form-group mx-auto text-center">
<input type="hidden" name="cap_hidden" value="<?php echo $_SESSION['secure']; ?>">
<img src="out.png">
</div>
I have found one similar question but it didnt help me, thats why I have posted it here.
The problem is the image is generated with lines only but no numbers are visible.

Answer 1

Looks like the font didn't load correctly.
Depending on which version of the GD library PHP is using, when fontfile does not begin with a leading / then .ttf will be appended to the filename and the library will attempt to search for that filename along a library-defined font path. PHP: imagettftext - Manual

Answer 2

I suppose there is Text on the Image but it is white.
Perhaps you could change the Colors of the Text.
http://php.net/manual/de/function.imagecolorallocate.php
These parameters are integers between 0 and 255 or hexadecimals
between 0x00 and 0xFF.
0 would be Black and 255 would be White.
You might want to look at the Example at
http://php.net/manual/en/function.imagettftext.php
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $white);
// The text to draw
$text = 'Testing...';
// Replace path by your own font path
$font = 'arial.ttf';
// Add some shadow to the text
imagettftext($im, 20, 0, 11, 21, $grey, $font, $text);
// Add the text
imagettftext($im, 20, 0, 10, 20, $black, $font, $text);
You also might have a look at your Script at:
$image=imagecreate($width, $height);
imagecolorallocate($image, 0, 0, 0);
$text_color=imagecolorallocate($image, 255, 255, 255);
The Result of imagecolorallocate($image, 0, 0, 0); isnt assigned anywhere.