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[css3-writing-modes] Align definition of 'upright' with San Diego f2f resolutions. Keep some informative text about caveats like Mongolian.
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‎css3-writing-modes/Overview.html‎

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@@ -1968,43 +1968,64 @@ <h4 id=vertical-orientations><span class=secno>5.1.1. </span> Vertical
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<h4 id=vertical-font-features><span class=secno>5.1.2. </span> Vertical
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Typesetting and Font Features</h4>
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<p>When typesetting text in vertical writing modes (‘<a
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href="#mixed-right"><code class=css>mixed-right</code></a>’ and ‘<a
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href="#upright"><code class=css>upright</code></a>’):
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<p>When typesetting text in ‘<a href="#mixed-right"><code
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class=css>mixed-right</code></a>’ and ‘<a href="#upright"><code
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class=css>upright</code></a>’ orientations:
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<ul>
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<li>Upright characters are typeset with vertical font metrics. The UA must
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synthesize vertical font metrics for fonts that lack them. (This
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specification does not define heuristics for synthesizing such metrics.)
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Additionally, font features (such as alternate glyphs) intended for use
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in vertical typesetting must be used. (E.g. the OpenType ‘<code
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<dl>
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<dt>upright characters
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<dd> Are typeset with vertical font metrics. The UA must synthesize
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vertical font metrics for fonts that lack them. (This specification does
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not define heuristics for synthesizing such metrics.) Additionally, font
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features (such as alternate glyphs) intended for use in vertical
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typesetting must be used. (E.g. the OpenType ‘<code
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class=css>vert</code>’ feature must be enabled.) Furthermore,
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characters from horizontal cursive scripts (such as Arabic) are shaped in
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their isolated forms when typeset upright.
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<p> The one exception is for <a href="#character"><i>characters</i></a>
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from the Mongolian and Phags-pa scripts, which in OpenType systems must
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always be rendered sideways (see below). This is because the "upright"
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orientation in the Unicode code charts and the "upright" orientation of
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the glyphs of these scripts in most OpenType fonts don't match.
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<li>Sideways characters are typeset with horizontal metrics, and vertical
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typesetting features are not used. However, if the font has features
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meant to be enabled for sideways text that is typeset in vertical lines
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(e.g. to adjust brush stroke angles or alignment), those features are
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used.
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<p class=issue>Propose ‘<code class=property>svrt</code>’ as an
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OpenType substitution feature that is applied to rotated horizontal text
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in vertical text runs, to handle these cases.
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</ul>
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<p class=note> Note that in OpenType systems, <a
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href="#character"><i>characters</i></a> from the Mongolian and Phags-pa
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scripts must actually be rendered <a
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href="#typeset-sideways">sideways</a>. This is because the "upright"
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orientation in the Unicode code charts (which assume vertical
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typesetting) and the "upright" orientation of the glyphs of these
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scripts in most OpenType fonts (which assume horizontal typesetting)
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don't match.
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<p class=note>Note that even when typeset "upright", some glyphs should
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appear rotated. For example, dashes and enclosing punctuation (such as
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〈 LEFT ANGLE BRACKET U+3008) should be oriented relative to the inline
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axis. In OpenType, this is typically handled by glyph substitution,
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although not all fonts have alternate glyphs for all relevant
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codepoints. (East Asian fonts usually provide alternates for East Asian
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codepoints, but Western fonts typically lack any vertical typesetting
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features.) Unicode published draft data on which <a
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href="#character"><i>characters</i></a> should appear sideways as the
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SVO property in <a
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href="http://www.unicode.org/reports/tr50/tr50-6.Orientation.txt">this
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data file</a>; however, this property has been abandoned for future
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revisions of <a href="#UTR50"
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rel=biblioentry>[UTR50]<!--{{!UTR50}}--></a>.
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<dt id=typeset-sideways>sideways characters
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<dd> Are typeset with horizontal metrics, and vertical typesetting
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features are not used. However, if the font has features meant to be
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enabled for sideways text that is typeset in vertical lines (e.g. to
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adjust brush stroke angles or alignment), those features are used.
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<!--<p class="issue">Propose 'svrt' as an OpenType substitution feature
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that is applied to rotated horizontal text in vertical text runs,
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to handle these cases.-->
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</dl>
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<p> All text in ‘<a href="#sideways"><code
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class=css>sideways</code></a>’, ‘<a href="#sideways-right"><code
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class=css>sideways-right</code></a>’, and ‘<a
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href="#sideways-left"><code class=css>sideways-left</code></a>’ modes is
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typeset using horizontal font metrics and the normal set of features used
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for horizontal text runs. Vertical metrics, vertical glyph variations, and
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any other features meant for text typeset in vertical lines are
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<em>not</em> used.
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href="#sideways-left"><code class=css>sideways-left</code></a>’
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orientations is typeset using horizontal font metrics and the normal set
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of features used for horizontal text runs. Vertical metrics, vertical
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glyph variations, and any other features meant for text typeset in
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vertical lines are <em>not</em> used.
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<p class=issue>This section needs additional work. Suggestions are welcome.
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<!-- random notes

‎css3-writing-modes/Overview.src.html‎

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@@ -1371,36 +1371,54 @@ <h4 id='vertical-orientations'>
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<h4 id='vertical-font-features'>
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Vertical Typesetting and Font Features</h4>
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<p>When typesetting text in vertical writing modes (''mixed-right'' and ''upright''):
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<p>When typesetting text in ''mixed-right'' and ''upright'' orientations:
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<ul>
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<li>Upright characters are typeset with vertical font metrics.
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<dl>
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<dt>upright characters
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<dd>
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Are typeset with vertical font metrics.
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The UA must synthesize vertical font metrics for fonts that lack them.
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(This specification does not define heuristics for synthesizing such metrics.)
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Additionally, font features (such as alternate glyphs) intended
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for use in vertical typesetting must be used.
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(E.g. the OpenType ''vert'' feature must be enabled.)
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Furthermore, characters from horizontal cursive scripts (such as Arabic)
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are shaped in their isolated forms when typeset upright.
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<p>
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The one exception is for <i>characters</i> from the Mongolian and Phags-pa scripts,
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which in OpenType systems must always be rendered sideways (see below).
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This is because the "upright" orientation in the Unicode code charts
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and the "upright" orientation of the glyphs of these scripts in most OpenType fonts
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<p class="note">
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Note that in OpenType systems,
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<i>characters</i> from the Mongolian and Phags-pa scripts
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must actually be rendered <a href="#typeset-sideways">sideways</a>.
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This is because the "upright" orientation in the Unicode code charts (which assume vertical typesetting)
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and the "upright" orientation of the glyphs of these scripts in most OpenType fonts (which assume horizontal typesetting)
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don't match.
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<li>Sideways characters are typeset with horizontal metrics,
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<p class="note">Note that even when typeset "upright",
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some glyphs should appear rotated.
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For example, dashes and enclosing punctuation
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(such as 〈 LEFT ANGLE BRACKET U+3008)
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should be oriented relative to the inline axis.
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In OpenType, this is typically handled by glyph substitution,
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although not all fonts have alternate glyphs for all relevant codepoints.
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(East Asian fonts usually provide alternates for East Asian codepoints,
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but Western fonts typically lack any vertical typesetting features.)
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Unicode published draft data on which <i>characters</i> should appear sideways
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as the SVO property in <a href="http://www.unicode.org/reports/tr50/tr50-6.Orientation.txt">this data file</a>;
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however, this property has been abandoned for future revisions of [[!UTR50]].
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<dt id='typeset-sideways'>sideways characters
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<dd>
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Are typeset with horizontal metrics,
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and vertical typesetting features are not used.
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However, if the font has features meant to be enabled
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for sideways text that is typeset in vertical lines
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(e.g. to adjust brush stroke angles or alignment),
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those features are used.
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<p class="issue">Propose 'svrt' as an OpenType substitution feature
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<!--<p class="issue">Propose 'svrt' as an OpenType substitution feature
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that is applied to rotated horizontal text in vertical text runs,
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to handle these cases.
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</ul>
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to handle these cases.-->
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</dl>
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<p>
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All text in ''sideways'', ''sideways-right'', and ''sideways-left'' modes is
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All text in ''sideways'', ''sideways-right'', and ''sideways-left'' orientations is
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typeset using horizontal font metrics and the normal set of features
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used for horizontal text runs.
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Vertical metrics, vertical glyph variations, and any other features meant

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