when viewing a website with [style=text-align:justify] firefox will scroll more slowly than internet explorer

UNCONFIRMED
Unassigned
(NeedInfo from)

Status

()

Core
Layout: View Rendering
UNCONFIRMED
12 years ago
a year ago

People

(Reporter: Nick, Unassigned, NeedInfo)

Tracking

Trunk
x86
Windows XP
Points:
---

Firefox Tracking Flags

(Not tracked)

Details

Attachments

(2 attachments)

(Reporter)

Description

12 years ago
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; de-DE; rv:1.7.8) Gecko/20050511 Firefox/1.0.4
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; de-DE; rv:1.7.8) Gecko/20050511 Firefox/1.0.4

when viewing a website with [style=text-align:justify] firefox will scroll more
slowly than internet explorer

Reproducible: Always

Steps to Reproduce:
1. Load a webiste with text formatted with css as text-align:justify
2.
3.

Actual Results:  
Scrolling with mouse or keyboard is slow

Expected Results:  
scroll more faster like internet explorer
can you give an example url ?

Comment 2

12 years ago
Created attachment 191292 [details]
Lots of text without justify.

Comment 3

12 years ago
Created attachment 191293 [details]
Lots of text with justify.

Comment 4

12 years ago
Confirmed Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b4)
Gecko/20050801 Firefox/1.0+ ID:2005080114

attachment 191293 [details] causes my cpu to max out while scrolling as hard as possible,
but attachment 191292 [details] does not use more than 22% of my cpu when scrolling as
hard as possible.

Comment 5

12 years ago
Comparing the speed of scrolling on nojustify on Firefox vs. IE (Firefox seems
inherently slower than IE in perceived scrolling speed so there needs to be some
normalization) to the speed of scrolling of justify on Firefox vs. IE, there
does to seem to be some slowdown in Firefox on justify (while there's
perceivably none in IE). When doing really fast scroling with AutoScroll or
dragging the scrollbar, Firefox has redraw problems, which seems to be slowing
the speed (perceivable speed or actual speed, I dunno).

Might not actually be a bug though. Firefox and IE probably having different
scroll code is causing it. More like a "Make scrolling more efficient" bug.

Updated

12 years ago
Assignee: nobody → roc
Component: General → Layout: View Rendering
Product: Firefox → Core
QA Contact: general → ian
Version: unspecified → Trunk
This is just the fact that justification forces us to take the slow text
painting path. Let's look at this again once all the 1.9 stuff has happened.

Comment 7

10 years ago
I noticed that in firefox 2.0.0.8 in the just released Fedora 8,
rendering and scrolling of justified text is _very_ slow.

redhat are on for punting this upstream. Details are here:
https://bugzilla.redhat.com/show_bug.cgi?id=374251

Can we change this to a cross platform bug, or
will I add a new bug?
Can you check whether a trunk nightly is better? It should be.

Assuming this is not a regression during the 2.0.0.x series, we wouldn't want to do anything about it on branch.

Comment 9

10 years ago
opera and ff-trunk about same speed now. yay!

a simple page of 10000 justified words was _really_ slow on ff-2.0.0.8 on linux.
Now scrolls extremely fast.
a smaller but slightly more complex page was quite slow on ff-2.0.0.8,
but now is quite fast.

smoothscroll is off by default on trunk whereas on by default in F8.
The difference between on & off in ff-trunk is very noticeable (as you would expect), whereas turning off smoothscroll on 2.0.0.8 in F8 doesn't help much

I would appreciate if you could give me any pointers as to what changed,
wrt justified text rendering. The difference is amazing.

I'm not sure if it's a regression in the 2.0.0.x series. I'm guessing
I'm noticing it now because of the combination of Fedora 8 defaults?
It is horrendous though for all pages using justified text, and would
be great if a fix could be merged from trunk.

Note ff-2.0.0.8 on windows is just as fast as ff-trunk on linux,
which suggests the fix to port could be quite small?

cheers,
Pádraig.
> I would appreciate if you could give me any pointers as to what changed,
> wrt justified text rendering.

We rewrote it.

I suspect the problem you're seeing is largely due to the Red Hat Pango patches for FF2. We use Pango very differently in FF3, in a way that's much more sensible and fast, especially for justified text.
QA Contact: ian → layout.view-rendering
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Assignee: roc → nobody
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