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<title>Fixed Point Kerning Table in OpenType fonts</title>

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<section class="main">

<h1>Fixed Point Kerning Table (FK, Version 1.0)</h1>
The FK table is a simple and efficient solution that makes it possible to store
kerning information with a high accuracy in OpenType fonts.

<h2>Names</h2>
The table name for horizontal kerning is "FK" and the table name for vertical 
kerning is "FKV". The name should be padded up to four bytes with space in the
TTF and OTF lists of tables (just like the CFF table). Name: FK space space

<h2>Table</h2>
<pre>
uint16 version_upper = 1;
uint16 version_lower = 0;
uint32 num_kerning_pair_entries;
KerningEntry[]

KerningEntry
uint32 first_glyph_index
uint32 second_glyph_index
fixed16_16 kerning
</pre>

<p>Padding up to four bytes will not be needed because the table already is aligned.</p>

<p>The type fixed16_16 is a fixed point value (16.16) that uses 32 bits, similar to the 255 type in the CFF table.</p>

<p>All kerning entries needs to be sorted on the first and second glyph ID (GID).</p>
</section>

<section class="data">

<h2>Example data</h2>
<pre>
<table>
<tr>
   <td>Type</td>
   <td>Hex</td>
   <td>Decimal</td>
   <td>Description</td>
</tr>

<tr>
   <td>USHORT</td>
   <td>0x0001</td>
   <td class="right">1</td>
   <td>Major verison</td>
</tr>

<tr>
   <td>USHORT</td>
   <td>0x0000</td>
   <td class="right">0</td>
   <td>Minor version</td>
</tr>

<tr>
   <td>ULONG</td>
   <td>0x00000002</td>
   <td class="right">2</td>
   <td>Number of kerning pairs</td>
</tr>

<tr class="empty">
    <td colspan="4"></td>
</tr>

<tr>
   <td>ULONG</td>
   <td>0x00000007</td>
   <td class="right">7</td>
   <td>First GID of the pair (left in LTR languages)</td>
</tr>

<tr>
   <td>ULONG</td>
   <td>0x00000008</td>
   <td class="right">8</td>
   <td>Second GID of the pair (right in LTR languages)</td>
</tr>

<tr>
   <td>Fixed</td>
   <td>0xffffcccc</td>
   <td class="right">-0.2</td>
   <td>Kerning for this pair</td>
</tr>

<tr class="empty">
    <td colspan="4"></td>
</tr>

<tr>
   <td>ULONG</td>
   <td>0x0000000A</td>
   <td class="right">10</td>
   <td>First GID of the second  pair (left in LTR languages)</td>
</tr>

<tr>
   <td>ULONG</td>
   <td>0x0000000F</td>
   <td class="right">15</td>
   <td>Second GID of second the pair (right in LTR languages)</td>
</tr>

<tr>
   <td>Fixed</td>
   <td>0xffffe666</td>
   <td class="right">-0.1</td>
   <td>Kerning for this pair</td>
</tr>
</table>
</pre>

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