<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Angsana New";
panose-1:2 2 6 3 5 4 5 2 3 4;}
@font-face
{font-family:"Cordia New";
panose-1:2 11 3 4 2 2 2 2 2 4;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
font-size:10.0pt;
font-family:"Courier New";}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:Consolas;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Thanks, John. That’s consistent with what I was expecting. And so I think that feature description really needs to be revised.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><a href="https://github.com/MicrosoftDocs/typography-issues/issues/622">Issue 622: 'curs' should be required for some scripts</a><o:p></o:p></p>
<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>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> mpeg-otspec <mpeg-otspec-bounces@lists.aau.at> <b>
On Behalf Of </b>John Hudson<br>
<b>Sent:</b> Monday, September 14, 2020 11:40 AM<br>
<b>To:</b> mpeg-otspec@lists.aau.at<br>
<b>Subject:</b> Re: [MPEG-OTSPEC] 'curs' feature: required?<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On 14092020 11:29 am, Peter Constable wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-CA">Is the ‘curs’ feature considered a required feature for Arabic or other cursively-connecting scripts?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-CA"> I would have expected it’s required. It’s clear the intent is for triggering cursive attachment positioning (GPOS type 3), and
<a href="https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Ftypography%2Fscript-development%2Farabic&data=02%7C01%7C%7Cb4dfdb44486d4751fcae08d858dd8e0f%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637357055874456434&sdata=rGbpCQGuYZaBJA6RORiqWe4f3r%2Fhetmd91mx5jnrExA%3D&reserved=0">
Microsoft’s Arabic implementation spec</a> lists it among features to be applied in GPOS processing. But the
<a href="https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Ftypography%2Fopentype%2Fspec%2Ffeatures_ae%23tag-curs&data=02%7C01%7C%7Cb4dfdb44486d4751fcae08d858dd8e0f%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637357055874466422&sdata=8Yar57Rrb8cXmQ5uQ3tv4K66DYk4VWxhVvzBgYdUJA8%3D&reserved=0">
description in the OTL feature registry</a> is worded in a way that makes it sound optional, at the user’s discretion:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-CA"> “</span><em><span style="font-size:12.0pt;font-family:"Calibri",sans-serif">UI suggestion:</span></em><span style="font-size:12.0pt"> This feature could be made
active or inactive by default, at the user’s preference.</span><span lang="EN-CA">”</span><o:p></o:p></p>
</blockquote>
<p>Based on Arabic fonts I have worked on or examined, I would say this definitely should not be optionally active, and if present the curs feature is expected to be applied by default. Indeed, a lot of fonts simply break if curs is not applied.<o:p></o:p></p>
<p>If a font contains support for different kinds of Arabic layout, e.g. a simplified layout with only horizontal connections and a more sophisticated display with some amount of vertical connections or cascading connections, then the curs support required
for the latter still needs to be applied by default, and the differentiation of the layout styles would be implemented, somehow, in GSUB, setting up the glyphs that either will or will not require curs attachment in GPOS.<o:p></o:p></p>
<p>JH<o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>John Hudson<o:p></o:p></pre>
<pre>Tiro Typeworks Ltd <a href="https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.tiro.com%2F&data=02%7C01%7C%7Cb4dfdb44486d4751fcae08d858dd8e0f%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637357055874466422&sdata=8ouyKx5fsW93YCT3HlVgJ1HP7Yp%2FdqAfzl6O6x2Olfo%3D&reserved=0">www.tiro.com</a><o:p></o:p></pre>
<pre>Salish Sea, BC <a href="mailto:tiro@tiro.com">tiro@tiro.com</a><o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>NOTE: In the interests of productivity, I am currently <o:p></o:p></pre>
<pre>dealing with email on only two days per week, usually <o:p></o:p></pre>
<pre>Monday and Thursday unless this schedule is disrupted <o:p></o:p></pre>
<pre>by travel. If you need to contact me urgently, please <o:p></o:p></pre>
<pre>use some other method of communication. Thank you.<o:p></o:p></pre>
</div>
</body>
</html>