Returns the pixel height of a character in the specified font.
Parameters
font
Can be 1, 2, 3, 4, 5 for built-in
fonts in latin2 encoding (where higher numbers corresponding to larger fonts) or any of your
own font identifiers registered with imageloadfont().
Return Values
Returns the height of the pixel.
Examples
Example #1 Using imagefontheight() on built-in fonts