PDF display problem

Question

http://www.rotarycupar.org/display_syllabus.php?offset=0
See above for the problem - most characters missing.
All is visible on an iPhone, or on a PC.

Answer 1

Thanks for that correction, Tom. I'm no great authority on fonts (as you have noticed!).
The code I am using to generate the PDF files is from a package called TCPDF, and I'd built my program on an example file. This included the lines:
// Set font
// dejavusans is a UTF-8 Unicode font, if you only need to
// print standard ASCII chars, you can use core fonts like
// helvetica or times to reduce file size.
$pdf->SetFont('dejavusans', '', 4.5, '', true);
In trying to find out what was going on, I commented out the SetFont() line, and replaced it with:
$pdf->SetFont('helvetica', '', 4.5, '', true);
which has allowed my code to work on the iPad. Inspection of the definition of helvetica within the TCPDF package leads me to believe it's a 256 character font, so it's ASCII not Unicode, which is what I was trying to say in the first instance (I think...).