Bug 245924

Summary:	KMail becomes very slow by rare symbols in email
Product:	[Unmaintained] kmail	Reporter:	Gatoso <gatoso>
Component:	general	Assignee:	kdepim bugs <kdepim-bugs>
Status:	RESOLVED UNMAINTAINED
Severity:	normal	CC:	montel
Priority:	NOR
Version:	1.13.5
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Demonstration mbox file.

Description Gatoso 2010-07-27 18:26:07 UTC

Version:           1.13.5 (using KDE 4.4.5) 
OS:                Linux

I got an email that contains in their name these rare symbols: 영웅재중 (I believe these are letters japanese or chinese ). So when I try to visualize this email, KMail becomes very very slow and seems to hangs some seconds, but after it returns to the normality.

Here a screenshot of this email:

http://imagebin.ca/img/mfRTi9cd.png

Also, the same behaviour occurs on Konqueror

Reproducible: Always

Steps to Reproduce:
Get an email with these "rare symbols"

Try out to read it

Actual Results:  
KMail becomes very slow and seems to hangs some seconds, after ir returns to the normality

Expected Results:  
KMail should have their normal performance when these, rare symbols, are in a email

OS: Linux (i686) release 2.6.34-ARCH
Compiler: gcc

Comment 1 Laurent Montel 2010-07-30 10:04:54 UTC

Same problem in konqueror ? So it's a khtml pb I think and not a kmail problem

Comment 2 Nick Leverton 2013-09-17 15:12:58 UTC

Created attachment 82371 [details]
Demonstration mbox file.

Still an issue in KDE 4.11.1.  Good spot that the problem is the renderer, but problem there is that Kmail doesn't seem to allow choosing webkit, and always uses khtml.  (if I'm wrong then tell me how !).

So html mails with even a few non-Western chars (in my case Korean) can take a substantial time to render, during which time Kmail2 is frozen and unresponsive.

See the attached sample, which has been anonymised by replacing Latin characters with 'x' but leaving the Korean ones in place.  When choosing this mail to display, Kmail2 hangs stone cold unresponsive for almost 30 seconds until it has rendered it.  I do have suitable fonts installed.

Perhaps this bug should be duplicated, once for kmail to use a better renderer and once for khtml to fix its issue ?

Comment 3 Laurent Montel 2013-09-17 17:20:30 UTC

(In reply to comment #2)
> Created attachment 82371 [details]
> Demonstration mbox file.
> 
> Still an issue in KDE 4.11.1.  Good spot that the problem is the renderer,
> but problem there is that Kmail doesn't seem to allow choosing webkit, and
> always uses khtml.  (if I'm wrong then tell me how !).

yes you are :)
We use qtwebkit in kmail2

> 
> So html mails with even a few non-Western chars (in my case Korean) can take
> a substantial time to render, during which time Kmail2 is frozen and
> unresponsive.
> 
> See the attached sample, which has been anonymised by replacing Latin
> characters with 'x' but leaving the Korean ones in place.  When choosing
> this mail to display, Kmail2 hangs stone cold unresponsive for almost 30
> seconds until it has rendered it.  I do have suitable fonts installed.
> 
> Perhaps this bug should be duplicated, once for kmail to use a better
> renderer and once for khtml to fix its issue ?

not khtml issue if you can reproduce in kmail2

Comment 4 Laurent Montel 2013-09-17 17:24:25 UTC

Ok I need 2 seconds to render it.
it's because you html file is very big.
but perhaps I don't have correct fonts.
But it's not kmail bug but a qtwebkit bug.

Comment 5 Laurent Montel 2015-04-12 09:51:24 UTC

Thank you for taking the time to file a bug report.

KMail2 was released in 2011, and the entire code base went through significant changes. We are currently in the process of porting to Qt5 and KF5. It is unlikely that these bugs are still valid in KMail2.

We welcome you to try out KMail 2 with the KDE 4.14 release and give your feedback.