Support line breaking for Thai text

[Markpeak-users]

Line breaking is the big issue for Thai. Softwares
without Thai line breaking are unusable for ordinary
people, especially for DTP or graphics industry.

For your information, whitespaces are used to separate
between "sentences" or "phrases", not "words" as Latin
script. This is still different from East Asian
languages (CJK) which each character means one word. So
Thai line breaking needs dictionary to distinguish word
boundary and insert break points for display.

There are some Thai linebreaking library available on
major platforms (Windows, Linux, Mac):
- Windows applications can use Microsoft Uniscribe. IE
done this.
- Mac applications can use Apple own library,
integrated with OSX. Safari done this.
- Linux applications can use libthai, many GTK+ and Qt
applications use libthai for line breaking already.
- Another alternative library is ICU, which available
cross-platform too.

Since GTK+ and GNOME handle line breaking issue
perfectly via libthai and Inkscape is GTK+ application.
Adding line breaking for Inkscape is big advantafe for
Thai people. On Windows, it can use Uniscribe.

[poju (popjussi)]

This feature was implemented at some point.

[poju (popjussi)]

This is the SVG used to test. Using "นกนางนวล" and "เนื้อนวลนาง" as strings. The wbr happened at the correct point as the result shows correctly separated words based on dictionary.

[poju (popjussi)]

for reference "นกนางนวล" and "เนื้อนวลนาง" should be broke down like "นก-นางนวล" and "เนื้อ-นวล-นาง" since "นางนวล" is a single word you can't shrink the display width smaller than its width.

[poju (popjussi)]

Additional note. I am not sure if this is the feature of libthai or not. But I have it installed and it was loaded by Inkscape via Pango, afaiu.

[poju (popjussi)]

The screenshot was made from r14232 trunk at the time on Ubuntu 14.04 . BTW. Though I am sure this has been working for a long time but I don't know when.