3.6 Troubleshooting your installation

For 99% of the users this library will work directly with a recent installation of PHP without any problem.

Experience shows that most of the trouble are caused by either an old buggy version of the free-type TTF library or using an old antiquated version of the GD library. In order to narrow it down the problem the following steps is helpful.

1. If no background images are displayed (instead a solid black box are displayed) chances are that GD 2.x is available but the jpg-config.inc.php has been changed so that true color images are disabled. Correct this by enabling the USE_TRUECOLOR define.
2. If background images does not work make sure the settings of USE_GD2_LIBRARY corresponds to the actual installation, i.e. If the GD2 library is not available then this define must be false!
3. If you are running IIS and Win2k and get the error "Can't find font" when trying to use TTF fonts then try to change the paths to UNIX style, i.e. "/usr/local/fonts/ttf/". Remember that the path is absolute and not relative to the htdocs catalogue.
4. If no images and no error messages gets sent back to the browser then there is a big chance that HTTP-Server PHP module (e.g. Apache-PHP) has crashed. This is often due to a broken PHP installation and more than often a problem with the True Type libraries. The best way to track these types of problem down is to investigate the HTTP-Server logs or the general system logs for evidence of a PHP crash. The other reasons is that in some rare cases the auto detection of the GD library could fail. If only the GD1 library is available and the JpGraph library mistakenly detects the GD2 this could in rare cases cause PHP to crash. Please try re-run the example by setting the DEFINE USE_GD2_LIBRARY to "false".
5. If the system is running IIS on Windows and some images which uses TTF fonts just return an empty page then try to set the TTF_DIR path manually (in jpg-config.php) to the directory where all the TTF fonts are stored (normally c:/WINDOWS/fonts)
6. If the cache is enabled please make sure that the permissions are correctly set for the cache directory so that the process running Apache/PHP has write access to the cache directory.
7. If the TTF fonts only shows up as yellow then you have a buggy installation of the freetype font library and the only thing to do is to re-install and setup PHP+GD again.