Hi Jeremy, I have developed a solution based on Harfbuzz and ICU for rendering Unicode text with C++ and OpenGL from the ground-up: https://github.com/arielm/Unicode
The topic of line-breaking is also on my agenda (more on the long term, nothing urgent...) One of the directions I'm planning to check in the future: https://github.com/adah1972/libunibreak I wonder how do you handle topics like font-fallback, script-itemization and BIDI, prior to shaping and line-breaking? Regarding one of your questions, it's easy to pass to Harfbuzz some text previously processed with ICU, as demonstrated here: https://github.com/arielm/Unicode/blob/v4.0.0/Projects/Rendering/src/TextRun.h#L50 HTH, Ariel http://chronotext.org On Sat, Feb 8, 2014 at 12:01 AM, Jeremy Moles <[email protected]> wrote: > Hey guys! I'm working on a Python3-based OpenGL library and I want to use > the union of Harfbuzz and libicu to do some (a small subset) of what Pango > currently does. I cannot, unfortunately, simply use Pango, as its > dependency chain will likely stop my clients' interest dead in its tracks. > Further, there are some issues when customizing Pango's rendering model > (and I'm not speaking without experience here, I've done it when I wrote > osgPango) that aren't ideal to work with. > > So, I would like to use hb and icu to accomplish some very basic layout in > my OpenGL scenes (note: I will also be using Glyphy instead of my own > rasterized SDF font textures too). I will need basic left|right|center > alignment (potentitally justify, but it isn't a request yet), some basic > markup support, etc. > > I nearly have everything working locally, but the one area I'm having a > lot of trouble with is knowing how--and in fact, WHOSE responsibility it > is--to determine how to break large lines of text given my sizing > constraints. This doesn't appear to be something harfbuzz attempts to do, > but it may have helper functions nonetheless. > > What I'm looking for are a few hints on how people (Behdad?) might tackle > this problem. ALL text in this library gets converted in > whitespace-normalized UTF8 using libicu and line breaks can only be FORCED > by using <p/> or <br/> markup. Otherwise, all breaks should behave > similarly to how they do in HTML. > > If I feed my force-delimited lines of text (that is, break my input feed > up by <br>/<p>) one huge chunk at a time to harfbuzz, I can get the extents > for each glyph as if I had unlimited X coordinate space. I can use these > extents to position as required by the calling function, but again, I'm > having trouble determining where it is safe to break. > > Is this something libicu can handle? Can harfbuzz make it easier? > > NOTE: When I "whitespace normalize" my string before ever passing it > harfbuzz, I use the UBRK API of libicu. There are also functions like: > > u_isspace() > > ...which look promising, but it expects a UChar32, which I do not know how > to easily fetch while using harfbuzz's UTF8 functions, who operate on > potential multibyte chars. > > Thanks in advance! > _______________________________________________ > HarfBuzz mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/harfbuzz >
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