Text wrapping is wrong for RTL languages

[tomh]

This was originally raised on the OSM trac (http://trac.openstreetmap.org/ticket/1515) and an example of the problem can be seen at http://www.openstreetmap.org/?lat=31.42411&lon=34.33985&zoom=16&layers=B000FTF.

When a label such as "مخيّم دير البلح" which is written in a right-to-left language like Arabic is rendered and has to be split across multiple lines the line splitting is done as if it was a left-to-right language.

So in this case it puts "البلح" on the first line and "مخيّم دير" on the second, but the first word of that name is actually "مخيّم" as this is an RTL language, so it is that which should be on the first line, and the rest of the text on the second line.

[artem]

Good catch. Yes, it needs fixing. Jon Burgess pointed me to http://vimgadgets.sourceforge.net/liblinebreak/. It solves different problem but we can adopt some better strategies for text splitting in general. Moving to 0.7.0

[Ldp]

#409 has been marked as a duplicate of this ticket.

[adamk]

As I mentioned in #409, I'd love to help and fix this problem. All I need is some initial guidance to get me going - e.g which module/source-file seems to be the most relevant - and I'll continue on my own from there. Thanks!

[springmeyer]

Hey adamk,

Take a look at: source:trunk/include/mapnik/font_engine_freetype.hpp where much of the text code is. Also, likely a good idea to take a look at http://www.pango.org/ to get a sense of how they solve this problem.