Summary

Proposal owner: Miklos Vajna

Proposal short name: Bottom to top, left to right writing direction

Rationale

Use cases:

Users sometimes want to have a text direction which is similar to latin text
(left to right, then top to bottom), but rotated 90 degrees counter-clockwise.

Also, this improves consistency, as doing the same in the clockwise direction
is already possible (the top to bottom, right to left direction is used for
e.g. Japanese text).

Alternatives considered:

It is possible to rotate characters at a span level, but that only gives
similar result as long as the content fits a single line.

Requested changes to the ODF Standard

Text changes/additions (compared to ODF 1.2):

20.394.2 <style:graphic-properties> (existing section)

Append to the end of style:writing-mode attribute value list: bt-lr.

20.394.3 <style:page-layout-properties> (existing section)

Append to the end of style:writing-mode attribute value list: bt-lr.

20.394.4 <style:paragraph-properties> (existing section)

Append to the end of style:writing-mode attribute value list: bt-lr.

20.394.5 <style:section-properties> (existing section)

Append to the end of style:writing-mode attribute value list: bt-lr.

20.394.6 <style:table-cell-properties> (existing section)

Append to the end of style:writing-mode attribute value list: bt-lr.

20.394.7 <style:table-properties> (existing section)

Append to the end of style:writing-mode attribute value list: bt-lr.

Schema changes/additions:

<rng:define name="common-writing-mode-attlist">
  <rng:optional>
    <rng:attribute name="style:writing-mode">
      <rng:choice>
        <rng:value>lr-tb</rng:value>
        <rng:value>rl-tb</rng:value>
        <rng:value>tb-rl</rng:value>
        <rng:value>tb-lr</rng:value>
        <rng:value>lr</rng:value>
        <rng:value>rl</rng:value>
        <rng:value>tb</rng:value>
        <rng:value>page</rng:value>
        <rng:value>bt-lr</rng:value>
      </rng:choice>
    </rng:attribute>
  </rng:optional>
</rng:define>

In other words, allow bt-lr as a new value of the style:writing-mode
attribute.

Impacts

Conformance:

This proposal will not add any mandatory features or behaviors.

Backwards compatibility:

This change will not impact existing ODF processors, the usage of the new
attribute value is optional.

Accessibility impact:

This change will not impact accessibility.

Interoperability:

OOXML's wordprocessingML has a <w:textDirection w:val="btLr"/> markup to
describe the same, this proposal allows roundtripping that feature in ODF.
LibreOffice 6.3 implements this layout feature in its ODF extension namespace.