201746 - RFE: Enable Complex Text Layout in the default build

Status: RESOLVED WONTFIX

(Core :: Layout: Text and Fonts, defect)

Description

[Roland Mainz]

RFE: Enable Complex Text Layout(=CTL) in the default build that Thai/hindi/tamil
users can use Mozilla to view web pages in their native languages (just try
http://www.mozilla.org/projects/mathml/start-thai.xml :) ...

ToDo:
- Turn the current switch --enable-ctl into --disable-ctl

I'll mark some bugs as blockers for this one - when they all have been resolved
we're ready to turn the CTL support "on" by default

Comment 1

[Roland Mainz]

mkaply:
Can you check whether CTL works on OS/2, please ?

Comment 2

[Mike Kaply [:mkaply]]

Nope, please don't enable this for Os/2. We need an updated glib with gmodule
support.

Comment 3

[Roland Mainz]

Michael Kaply wrote:
> Nope, please don't enable this for Os/2. We need an updated glib with gmodule
> support.

There is likely still some work todo (like your OS/2 issue) before we can enable
this - don't worry... :)
... can you file a bug for your problem and mark it as blocker for this bug,
please ?

Comment 4

[Roland Mainz]

BTW: The OS/2 problem with gmodule support may be fixed by a possible solution
for bug 201747 ("RFE: Replace hack for StaticBuilds with conformant solution").
We could simply build these libs statically by default (for all platforms or
only for OS/2), removing the need for gmodule support...

Comment 5

[Jungshik Shin]

Would it be possible to turn this on for Linux/Unix builds
by default if OS/2 issue won't be resolved soon? With a few 
simple patches (bug 204039, bug 204286, bug 203252) and one 
big patch(bug 176290), Mozilla-Xft can render Devanagari, Thai,
and Tamil reasonably well. (Mozilla-X11core would render Devanagari
and Thai as it is.) This is also the case of some other
Indic scripts (bug 204439: Prabhat has written shapers for them).

Comment 6

[timeless]

Um, before you do this, i'd like to figure out how this affects bezilla.
I'm not sure how much sense it makes to build pango on BeOS, or whether any of
this really works on BeOS (yes i'm building w/ CTL, but no I haven't done any
testing of it).

I'd also kind of like to get the CTL code cleaned up a bit, although that's not
essential and the intl code which is already built by default needs cleaning, so
it's not like anyone really cares about that.

Comment 7

[Jungshik Shin]

timeless, Prabhat has a patch to clean up CTL code in bug 203406. I'm also aware
that you have a patch to remove some warnings bet. the comparsion of signed and
unsigned. It'd be nice to land prabhat's patch (203406), yours and mine (bug
204286.) 

As for BeOS, how is MathML supported on BeOS? Does it use
fontEncoding.properties file as is the case of Mozilla-Win, Mozilla-MacOS
(classic) and Mozilla-Xft? If it does and BeOS doesn't have the native support
of complex script rendering with opentype fonts on par with Windows 2k/XP,  it
can benefit from CTL via bug 204286/bug 203252 (and  bug 204039/bug 176315 in
the future if they're recast under the CTL umbrella).

Anyway, if the impact of turning this on other platforms is not clear, we may
just turn it on for Unix-like systems. 

Comment 8

[Alok Kumar]

I Think enabling it for *nix builds would be a good idea. 

Unless there is some policy about not enabling a particular switch for a
specific platform.

Comment 9

[Jungshik Shin]

> enabling it for *nix builds would be a good idea 
 
There's one issue to resolve before enabling CTL (on Unix) by default. When 
CTL is enabled (for about three months, I've been using CTL-enabled Xft 
builds), the cursor movement in textarea is irratic. IIRC, there's a bug filed 
for this bug, but apparently it's not filed under 'CTL component' and I 
couldn't find it.  If anybody knows the bug, it'd be nice if this bug is made 
dependent on it.  

Comment 10

[Jungshik Shin]

Another road block to fixing this is bug 189433.  
 
As for the bug I mentioned in comment #9, I couldn't find it. However, I found 
a bunch of related bugs and listed them in bug 206550. Prabhat wrote to me 
that he has a working patch in Sun Mozilla (the bug I'm trying to find also 
has his comment to that effect.) 

Comment 11

[Roland Mainz]

Update:
- The cursor movement issue has been solved
- GTK2 builds with CTL without problems

I'd like to fix this bug either for mozilla1.7beta or mozilla1.8alpha... any
objections against that ?

Comment 12

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I'd suggest 1.8alpha. 1.7beta is supposed to be done by tomorrow.

Comment 13

[Louie Zhao]

It's the right way to open CTL by default. The more user use this feature, the
more stable it will become. In Sun' internal mozilla codebase, CTL works fine in
most of the time.

Prabhat, can you make a patch for this?

Comment 14

[Eli Friedman]

WONTFIX?

Comment 15

[Simon Montagu :smontagu]

Totally.