<p dir="ltr">Would it make sense to propose having script or language system specific Ascender/Descender or Max/Min in CFR?<br>
One might want to have script specific or language specific line heights when compositing from multiple fonts. Whether these metrics are from the BASE table Max/Min or another source is an issue that needs to be clarified in OFF.</p>
<p dir="ltr">Cheers,</p>
<div class="gmail_quote">On 19 Nov 2013 19:02, "John Hudson" <<a href="mailto:john@tiro.ca">john@tiro.ca</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Vladimir wrote:<br>
<br>
> I am not sure if using OS/2 sTypo... values would be a good choice<br>
> because in the majority of fonts the actual values recorded in those<br>
> fields can't really be trusted.<br>
<br>
Also, the sTypoAscender and -Descender values are expected to be used in<br>
concert with the sTypoLinegap value, and without that third piece of<br>
information they are useless.<br>
<br>
> In particular, I would suggest to at least consider the following strategy:<br>
> - if the CFR <FontMetrics> element defines ascender and descender values<br>
> - the implementation will use the values defined by a CFR author;<br>
<br>
Perhaps we also need to look more closely at what it means to 'use'<br>
those metrics, in terms of the distinction that OS/2 metrics have at<br>
least tried to make between linespacing metrics and bounding box metrics<br>
(even if in practice the two have been conflated most of the time).<br>
<br>
> - if the ascender and descender values are not explicitly defined, the<br>
> implementation will use the first, highest-priority component font to<br>
> determine the ascender and descender values according to the algorithm<br>
> defined in the "Baseline to Baseline Distances" section of the OT/OFF<br>
> "Recommendations" clause.<br>
<br>
This seems like a step in the right direction. Will need to review those<br>
recommendations again, though.<br>
<br>
I understand that Google did a lot of cross-browser testing of<br>
linespacing behaviour, and as a result came up with recommendations for<br>
their webfonts that differ from the recommendations we've worked with on<br>
Microsoft fonts for the past decade.<br>
<br>
J.<br>
<br>
<br>
--<br>
<br>
Tiro Typeworks <a href="http://www.tiro.com" target="_blank">www.tiro.com</a><br>
Gulf Islands, BC <a href="mailto:tiro@tiro.com">tiro@tiro.com</a><br>
<br>
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<br>
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