SetFont(string family [, string style [, float size]])
Description
Sets the font used to print character strings. It is mandatory to call this method
at least once before printing text or the resulting document would not be valid.
The font can be either a standard one or a font added via the AddFont() method. Standard fonts
use the Windows encoding cp1252 (Western Europe).
The method can be called before the first page is created and the font is kept from page
to page.
If you just wish to change the current font size, it is simpler to call SetFontSize().
Note: the font definition files must be accessible. They are searched successively in:
The directory defined by the FPDF_FONTPATH constant (if this constant is defined)
The font directory located in the same directory as fpdf.php (if it exists)