imageloadfont() loads a user-defined bitmap font and returns an identifier for the font (that is always greater than 5, so it will not conflict with the built-in fonts).
The font file format is currently binary and architecture dependent. This means you should generate the font files on the same type of CPU as the machine you are running PHP on.
Tabella 1. Font file format
|byte position||C data type||description|
|byte 0-3||int||number of characters in the font|
|byte 4-7||int||value of first character in the font (often 32 for space)|
|byte 8-11||int||pixel width of each character|
|byte 12-15||int||pixel height of each character|
|byte 16-||char||array with character data, one byte per pixel in each character, for a total of (nchars*width*height) bytes.|