Image doesn't show up when font called within Joomla

Question

I'm new to Joomla dev and php so if I'm doing something stupid please let me know!

I'm creating a certificate to be printed after a user completes a quiz with their name, date, etc. I've gotten the image to show up and text, but when I add the font nothing shows up.

Here's the base script I'm using and works (background image and font working):

$image_file = 'images/certificate_page.png';
$my_img = imagecreatefrompng ($image_file);
$font_size_big = 24;
$text_colour = imagecolorallocate( $my_img, 0, 0, 0 );
$font_file = 'FelipaRegular.ttf';  

imagefttext( $my_img, $font_size_big, 0, 5, 75, $text_colour, $font_file, "test with font"); 
imagestring( $my_img, 4, 30, 25, "test without font", $text_color );

header( "Content-type: image/png" );
imagepng( $my_img );

imagecolordeallocate( $text_color );
imagedestroy( $my_img );

When I tried to apply it within Joomla the problems started. I'm calling it from within a template like this:

<img src="<?php echo JURI::root().'index.php?tmpl=certgenerator&quizmod='.$quizmod.'' ?>" />

and the file generator (certgenerator.php):

defined('_JEXEC') or die;
require_once("includes/variables_certificate.php");

$image_file = JURI::root().'templates/'.$this->template.'/images/certificate_page.png'; 
$my_img = imagecreatefrompng ($image_file);
$font_size_big = 24;
$text_color = imagecolorallocate( $my_img, 0, 255, 0 );
$font_file = 'FelipaRegular.ttf';  

imagefttext( $my_img, $font_size_big, 0, 55, 75, $text_color, $font_file, "why u no work"); //if commented out image displays but not font obviously, as it's written now it returns a blank page
imagestring( $my_img, 4, 30, 25, "works", $text_color ); //works but doesn't include font

header( "Content-type: image/png" );
imagepng( $my_img );

imagecolordeallocate( $text_color );
imagedestroy( $my_img );

Reference:

http://php.net/manual/en/function.imagettftext.php

I've tried imagettftext vs imagefttext, no extension, with extension, bunch of stuff from the link above, all the same result. Any ideas? I'm guessing (and hoping!) something stupid?

Answer 1

In your PHP when working with files you should use JPATH_ instead if JURI. JURI is used for generating http URIs.

$image_file = JURI::root().'templates/'.$this->template.'/images/certificate_page.png'; 

Should be

$image_file = JPATH_SITE.'/templates/'.$this->template.'/images/certificate_page.png'; 

Not sure if this is the problem, and your code may well work as I have a sneaky suspicion that imagecreatefrompng() accepts http. But really it is the wrong way to go about it as it is a local file.