Lao characters not rendering

[cc young]

when a Lao character has both a vowel and a tone mark above the consonant, the tone mark does not show.

consonant with vowel: ມື with tone mark: ม้ with both (tone mark above vowel) มื้

in gedit (as well as firefox and chrome!) the tone mark does not show if there is no white space above the line.

a second bug in gedit is that if the consonant is on the last line then cannot enter a vowel below the consonant, eg, ດູ. when you type it, only ດ appears. if you create a line beneath the line, then can go back and type in ດູ correctly.

do not think the problem with gedit. if not, please let me know the correct party.

this is a huge problem!! it is pretty much blocking used of Ubuntu in the country of Laos except for die hard fans.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gedit 3.4.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-59.90-generic 3.2.54
Uname: Linux 3.2.0-59-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Mon Mar 31 11:16:48 2014
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gedit
UpgradeStatus: No upgrade log present (probably fresh install)

[cc young (bangkokmaco)]

discussion of line height in Lao and Thai

in Lao and Thai, the amount of vertical space required depends on how high and how low vowels and tone marks are stacked on the consonant.

one can either select the max above and max below the consonant to determine a fixed line height, or one could analyze the line and set line height according to need.

the first approach is simpler, but usually results in a lot of wasted space. consonants with both a vowel and tone mark above probably occur in about 30% of the lines in a typical newspaper, for example.

below there are three occurrences: a character is a descender, eg, ຽ, a vowel below, eg, ດູ, and the weird ຫຼ. (ຫຼ with ອູ vowel beneath is theoretically possible but I can find no occurrences in the dictionary.) descenders occurr in about 30% of the lines in a newspaper.

letting descenders and stacked tone marks share the same space is possible if one horizontally adjusted the two lines to prevent collision. (fixed width font makes no sense in Lao or Thai.) this would allow a fixed line height that not too obscene, but kerning between lines is pretty weird.