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<p class="MsoNormal">An error in the ‘avar’ table chapter of the OT spec was just pointed out: the axisCount field was defined in OT as uint16, which matches what is used for the corresponding field in the ‘fvar’ and ‘gvar’ tables in both OT and Apple’s TrueType
spec. However, Apple’s ‘avar’ table spec used int32 for the axisCount field — I assume this was done to provide four-byte alignment of header fields. This was not noticed when the ‘avar’ chapter for the OT spec was drafted. But clearly compatibility with Apple’s
‘avar’ spec is necessary. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We’ve published errata for OT 1.8 and OT 1.8.1 with a correction for this issue.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><a href="https://www.microsoft.com/typography/otspec/errata.htm">https://www.microsoft.com/typography/otspec/errata.htm</a><o:p></o:p></p>
<p class="MsoNormal"><a href="https://www.microsoft.com/typography/otspec180/errata.htm">https://www.microsoft.com/typography/otspec180/errata.htm</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The ‘avar’ header is now documented as follows:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><i><span style="font-size:10.0pt;font-family:"Georgia",serif">Axis variation table:</span></i><span style="font-size:10.0pt;font-family:"Georgia",serif"><o:p></o:p></span></p>
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<td width="20%" style="width:20.0%;background:silver;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal" align="center" style="text-align:center"><i><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">Type<o:p></o:p></span></i></p>
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<td width="20%" style="width:20.0%;background:silver;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal" align="center" style="text-align:center"><i><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">Name<o:p></o:p></span></i></p>
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<td width="60%" style="width:60.0%;background:silver;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal" align="center" style="text-align:center"><i><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">Description<o:p></o:p></span></i></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">uint16<o:p></o:p></span></p>
</td>
<td valign="top" style="border:none;border-bottom:solid #E0E0E0 1.0pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">majorVersion<o:p></o:p></span></p>
</td>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">Major version number of the axis variations table — set to 1.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">uint16<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">minorVersion<o:p></o:p></span></p>
</td>
<td valign="top" style="border:none;border-bottom:solid #E0E0E0 1.0pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">Minor version number of the axis variations table — set to 0.<o:p></o:p></span></p>
</td>
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<tr>
<td valign="top" style="border:none;border-bottom:solid #E0E0E0 1.0pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif;background:yellow;mso-highlight:yellow">uint16<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif;background:yellow;mso-highlight:yellow"><reserved><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif;background:yellow;mso-highlight:yellow">Permanently reserved; set to zero.</span><span style="font-size:9.0pt;font-family:"Verdana",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif;background:yellow;mso-highlight:yellow">uint16<o:p></o:p></span></p>
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<td valign="top" style="border:none;border-bottom:solid #E0E0E0 1.0pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif;background:yellow;mso-highlight:yellow">axisCount<o:p></o:p></span></p>
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<td valign="top" style="border:none;border-bottom:solid #E0E0E0 1.0pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif;background:yellow;mso-highlight:yellow">The number of variation axes for this font. This must be the same number as axisCount in the 'fvar' table.</span><span style="font-size:9.0pt;font-family:"Verdana",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">SegmentMaps<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">axisSegmentMaps[axisCount]<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Verdana",sans-serif">The segment maps array — one segment map for each axis, in the order of axes specified in the 'fvar' table.<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Peter<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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