321735 - Increasing text size garbles bengali text rendering

Status: RESOLVED WORKSFORME

(Core :: Internationalization, defect)

Description

[blore_m75]

User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.12) Gecko/20050915 Firefox/1.0.7

renderning of the bengali text is broken:
"nihata" is rendered as "nahit" (misplaced "ii") -- in most of the places
its not even a valid readable word.


Reproducible: Always

Steps to Reproduce:
1. goto the site, click on some text news in bengali. may use ctrl+/-.
2. load in internet explorer too
3. see the differences with "matras" -- e.g. vowels in indian languages -- where they placed. in my case, they are placed one character after where it should be.

Actual Results:  
vowels in bengali text misplaced. they are put one char right.

Expected Results:  
vowels to be placed one char left.

might be happening with other indian language too.

Comment 1

[blore_m75]

url pasted above is a site using bengali fonts.
http://www.bbc.co.uk/bengali/

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Can you reproduce with Firefox 1.5 or Nightly builds?
And please attach the screenshot.

Comment 3

[Jungshik Shin]

Did you enable complex script rendering in Windows XP? MS IE does work without it being enabled, but Firefox doesn't. See also bug 218887 and bug 297074 if your problem is about 'justified text'. Firefox rendering breaks down for justified text in complex scripts. 

Comment 4

[blore_m75]

Attachment: screenshot, highlighted with pink circle

Comment 5

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

I cannot reproduce it like the screenshot with 2005122705-trunk/WinXP-JA.
Please re-test with Firefox1.5 or Nightly builds.

Jungshik:
> Did you enable complex script rendering in Windows XP?

What's this? WinXP's settings?

Comment 6

[Jungshik Shin]

(In reply to comment #5)

> Jungshik:
> > Did you enable complex script rendering in Windows XP?
> 
> What's this? WinXP's settings?

In 'control panel | regional options', you have to enable one of complex scripts (e.g. Thai, Hindi, Bengali, Tamil) to make the default string measuring/drawing APIs (used by us) work for complex scripts.  Read bug 218887 and bug 297074 as well the international release notes for mozilla suite (http://www.mozilla.org/releases/mozilla1.7/known-issues-int.html#display). Because you can't reproduce it, you must have already activated it. 
 
Anyway, the BBC Bengali site doesn't use 'text-justify' or related style spec (or html equivalents) so that it should just work. And it appeared so until I changed the text size with Ctrl-+ or Ctrl-'-'. Going back to the original size didn't help.  It's a bit surprising  that changing the text size breaks  the rendering this way. This operation might do something related to 'text justification' internally... (bz and dbaron, does this operation indeed do that?)  In that case, this bug definitely depends on bug 218887 and bug 297074.Somehow, this doesn't happen at the BBC Hindi (I'm not sure, though. I have to take a closer look)

Comment 7

[Boris Zbarsky [:bzbarsky]]

All changing text size does is recompute font sizes and reflow...

Comment 8

[blore_m75]

After enabling complex script rendering it works fine.
even with ctrl+ ctrl-.
(ive installed avro easy unicode keyboard before this test. hope that does
not affect it)

Comment 9

[Simon Montagu :smontagu]

Works correctly on current trunk.