KERN    (0x4B45524C)    /* Kerning pair */

The KERN chunk describes a kerning pair.  A kerning pair sets the
distance between a specific pair of characters.

    struct KERNstruct {
        short   Ch1, Ch2;   /* The pair to kern (allows for 16 bits...) */
        IEEE    XDisplace,  /* Amount to displace -left +right */
                YDisplace;  /* Amount to displace -down +up */
    };

The Ch1 and Ch2 fields contain the pair of characters to kern.  These
characters are typically stored as ASCII codes.  Notice that OFNT stores
the characters as a 16-bit value.  Normally, characters are stored as
8-bit values.  The wary programmer will be sure to cast assigns properly
to avoid problems with assigning an 8-bit value to a 16-bit variable.  The
remaining fields, XDisplace and YDisplace, supply the baseline shift from
Ch1 to Ch2.