Add simple line breaking support

[khaledhosny]

Just the basics (breaking at spaces and other simple break opportunities), just good enough for basic Arabic and Latin needs.

[khaledhosny]

grigorig/ucdn#7 should be helpful here. cc @mzn723.

[brawer]

Hm, when I use this in fontview, raqm enters an endless loop inside _raqm_line_break(). Specifically, in the loop for (size_t i = 0; i < glyph_count; i++) after the comment /* finding possible breaks in text */, the variable i stays at value 1 for every iteration. It gets of course increased on each loop iteration, but then it gets decreased again inside the loop. — To reproduce, check out fontview, uncomment the call to raqm_set_line_width() in src/fontview/sample_text.cpp and run git checkout linebreaking inside src/third_party/raqm/libraqm.

[khaledhosny]

I was debugging that a couple of weeks ago, and the current code in _raqm_line_break() is very fragile and I need to re-write it in a more robust way.

[brawer]

Thanks, much appreciated.

[brawer]

Curious, how’s the rewrite going?

[khaledhosny]

Not much unfortunately, didn’t have time to do Raqm hacking lately.

[brawer]

Curious, any updates? (Sorry for the nagging).

[khaledhosny]

No, unfortunately. I have been pretty busy with other stuff and right now I don’t know when I’ll have time again to look into this.

[ericoporto]

Hey, I am looking into this library because I wanted to use it along with Harfbuzz and FreeType for Persian, but I am a bit stuck at linebreaks, has there been any change in this issue?

[khaledhosny]

No one is actively working on this unfortunately, and I cam to the conclusion that this is best handled by an more actively maintained library, probably libunibreak than trying to replicate that work here, though I suspect some Raqm users might not appreciate the extra dependency.

[therahedwig]

No one is actively working on this unfortunately, and I cam to the conclusion that this is best handled by an more actively maintained library, probably libunibreak than trying to replicate that work here, though I suspect some Raqm users might not appreciate the extra dependency.

Hi, I was wondering, might it be an idea to have sort of wrapper functions around the linebreaking functionality, that library-consumers can then reimplement, much like harfbuzz has for it's unicode functions? This way this library can have some super-basic implementation for people who don't need much, and then people who need up-to-date linebreaking algos can use libunibreak or ICU directly.