Letters in Indian Language scripts




Layout: Text
14 years ago
10 years ago


(Reporter: Biju, Assigned: Prabhat Hegde)


Windows XP

Firefox Tracking Flags

(Not tracked)




(2 attachments)



14 years ago
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6b) Gecko/20031217 Firebird/0.7+
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6b) Gecko/20031217 Firebird/0.7+

In many Indian Language scripts, letters are formed by combining vowels and
constant. And depending on vowels - constant combination, position of the vowel
symbol may be in front, back, top or below of the constant. Sometimes
combination will produce a totally new character. But Mozillla/Firbird is not
doing that.

Sample page which show problem

Attachment Image shows both error cases.
Firebird - MS IE View

case 1 - vowel symbol not at proper position
case 2 - Mozilla not showing the right combined character

MozillaZine topic : Regarding Unicode

Reproducible: Always

Steps to Reproduce:
1. open http://trinetra.ncb.ernet.in/bharateeyaoo/download/OOG_Tamil.txt
2. compare same with MS-IE

Actual Results:  
see attachement

Expected Results:  
as in IE see attachement

Comment 1

14 years ago
Created attachment 139249 [details]
Firebird / MS IE View

Comment 2

14 years ago
Created attachment 139250 [details]
Firebird / MS IE View Original
Assignee: nobody → prabhat.hegde
Component: Layout: Fonts and Text → Layout: CTL
QA Contact: core.layout.fonts-and-text → art

Comment 5

14 years ago
Before filing a bug on CTL, please read the international release notes and bugs
refered to there.

On Windows 2k/XP, Mozilla already does a pretty reasonable job as far as
rendering unjustified text is concerned. You need to activate
Devanagari/Tamil/Thai and other complex script support in the control panel of
Windows XP/2k. 
Last Resolved: 14 years ago
Resolution: --- → INVALID
    To add to Biju's comment - indeed I could view on IE correctly the script
for my language . 
   Let us consider the page - http://www.thisaigal.com/oct/unitamcomp1.html . 
 "Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.6) Gecko/20040114
Firebird/0.7+ " . 
    This page is perfectly fine, when I view with IE . But when i view the same
with Firebird, the page is not pretty much clear. What could have been the
problem here. 

    Since i could view it with IE, indeed the fonts for the script should have
been installed on my system, I guess. 
    Hence reopening the bug. 

Comment 7

14 years ago
That has nothing to do with Mozilla's capability to render Tamil. The page uses
web fonts (MS's proprietary EOT font) not supported by Mozilla. If the author
had put in a graceful degradation path and you had turned on Tamil support[1] on
your Win2k/XP, Mozilla would be able to render it without any problem on Windows
2k/XP provided that it's unjustified. Ask the author to add a link to the font
download (opentype fonts instead of 'EOT').

 Several bugs have been filed on Indic and other complex script supports and
filing an invalid/duplicated bug doesn't help me a bit. See how many bugs are
listed at


[1] Mozilla uses standard Windows text drawing/measuring APIs while MS IE uses
Uniscribe APIs. The former does NOT work unless you activate one of complex
script support options (it doesn't matter whether it's Devanagari, Tamil, or
Thai although obviously you want to activate Tamil) whereas the latter works
without complex script support activated (as long as there are opentype fonts
for them).


10 years ago
Component: Layout: CTL → Layout: Text
QA Contact: arthit → layout.fonts-and-text
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