inline-base direction

[r12a]

11.1.1. Definitions
https://svgwg.org/svg2-draft/text.html#TermInlineBaseDirection

inline-base direction
The primary direction in which content is ordered within a line or part of a line of text. It defines the "start" and "end" sides of a line or part of a line of text (relevant, for example to how the text-anchor property is applied). It is determined by the direction property. (Note: the ordering of characters in a line of text is primary controlled by the Unicode bidi algorithm and not the inline-base direction.)

Not sure i understand the point in the last sentence (to which i added bolding). Depending on what characters are involved, it seems to me that the inline base direction is equally important as the bidi algorithm in laying out bidirectional text, since it informs the bidi algorithm about how to layout out the text.

[nikosandronikos]

I think that text is trying to make a distinction between ordering at the shaping level and the overall direction of word flow? I agree it's confusing and your understanding matches mine..

[nikosandronikos]

@Tavmjong Can we just reference the CSS Definition here?

[Tavmjong]

The bolded text could be rewritten to be clearer. It comes from SVG 1.1. The text is meant to warn, for example, that hebrew/arabic characters are laid out right-to-left regardless of the value of 'direction'.

[r12a]

Ah, ok. So something like:

A sequence of strongly-typed characters with the same direction will form a directional run, in which the characters are displayed visually in an order that corresponds to the directional type that they share. Thus an uninterrupted sequence of Hebrew letters will always be read from right to left. This ordering is produced by the Unicode Bidirectional Algorithm, and is independent of the setting of the inline-base direction. The inline-base direction, however, affects the order in which multiple different directional runs are displayed, and the positioning of weak or neutral characters that occur between directional runs with different directions.

(It glosses over the fact that two sequences of Hebrew letters with a space or punctuation between them becomes a single directional run.)