fribidi_reorder_line(3)

📦
version 1.0.18 · 5 versions
, in arch rolling

💅 fribidi_reorder_line(3) — like, the whole manual, bestie

okay so you've stumbled into the fribidi_reorder_line(3) page from the Programmer's Manual and honestly? you're about to have a good time. this one's a baddie. it takes your logical-order line and flips it into visual order. slay.

✨ NAME ✨

fribidi_reorder_line — reorder a line of logical string to visual. that's it. that's the whole vibe. 🦋

🎀 SYNOPSIS 🎀

#include <../fribidi/lib/fribidi.h>

FriBidiLevel fribidi_reorder_line
(
     FriBidiFlags flags,
     const FriBidiCharType *bidi_types,
     const FriBidiStrIndex len,
     const FriBidiStrIndex off,
     const FriBidiParType base_dir,
     FriBidiLevel *embedding_levels,
     FriBidiChar *visual_str,
     FriBidiStrIndex *map
);

look at all those parameters. main character energy fr. 🌟

🌸 PARAMETERS 🌸

  • FriBidiFlags flags — the reorder flags. short and sweet. 💫
  • const FriBidiCharType *bidi_types — the input list of bidi types, exactly as returned by fribidi_get_bidi_types(). and like… there are 23 possible values for a const FriBidiCharType, so bestie they are not all listed here. we'd be here all day. 🙈
  • const FriBidiStrIndex len — input length of the line. how long is she? 💅
  • const FriBidiStrIndex off — input offset of the beginning of the line in the paragraph. like, where does this line start inside the bigger paragraph. iykyk.
  • const FriBidiParType base_dir — the resolved paragraph base direction. and the possible values for a const FriBidiParType are:
    • FRIBIDI_PAR_LTR — Left-To-Right paragraph. ➡️
    • FRIBIDI_PAR_RTL — Right-To-Left paragraph. ⬅️
    • FRIBIDI_PAR_ON — DirectiOn-Neutral paragraph. (that capital O-N is literally how it's spelled, don't come for me 🫶)
    • FRIBIDI_PAR_WLTR — Weak Left To Right paragraph.
    • FRIBIDI_PAR_WRTL — Weak Right To Left paragraph.
  • FriBidiLevel *embedding_levels — the input list of embedding levels, as returned by fribidi_get_par_embedding_levels. yes, that one. 💜
  • FriBidiChar *visual_str — the visual string to reorder. this is the glow-up destination. ✨
  • FriBidiStrIndex *map — a map of string indices which is reordered to reflect where each glyph ends up. it's giving "tracking receipts for every character". 🔥

🦋 DESCRIPTION 🦋

okay so here's the tea. this function reorders the characters in a line of text from logical to final visual order. she's doing the actual heavy lifting. 🏋️‍♀️

no cap, this function implements part 4 of rule L1, plus rules L2 and L3 of the Unicode Bidirectional Algorithm, which lives right here: http://www.unicode.org/reports/tr9/#Reordering_Resolved_Levels — go read it, it's giving homework but it's iconic homework.

as a side effect it also sets position maps, but only if they're not NULL. so like, if you passed NULL, no maps for you. 🙈

you should provide the resolved paragraph direction and embedding levels as set by fribidi_get_par_embedding_levels(). also heads up bestie: the embedding levels may change a bit. to be exact — the embedding level of any sequence of white space at the end of line is reset to the paragraph embedding level. and that? that is part 4 of rule L1. don't forget it. 💀

⚠️ major note: the bidi types and embedding levels are not reordered. not even a little. you can reorder these (or any other) arrays using the map later. and the user is responsible to initialize map to something sensible — like an identity mapping — or just pass NULL if no map is needed. your call, your problem, your era. 💅

there's also an optional part to this function, and it's a whole thing: whether non-spacing marks for right-to-left parts of the text should be reordered to come after their base characters in the visual string, or not. most rendering engines expect this behavior, but console-based systems, for example, do not like it. literally do not. this is controlled by the FRIBIDI_FLAG_REORDER_NSM flag. and that flag is on in FRIBIDI_FLAGS_DEFAULT. so if you didn't know, now you know. 🧚

⭐ RETURNS ⭐

the maximum level found in this line plus one. or zero if any error occurred — memory allocation failure most probably. so if you get a zero, that's your sign to go touch some grass and check your allocations. 😭

🌈 SEE ALSO 🌈

the whole friend group, honestly. go say hi:

and that's the whole page, bestie. this lil doc came to you from c2man, out of fribidi-bidi.h, dated 29 October 2026, and it signs off under the name fribidi_reorder_line(3). periodt. 💖✨🎀

📦 where this page comes from