846470 - scrolling on marketplace.firefox.com is choppy

Status: RESOLVED FIXED

(Marketplace Graveyard :: General, defect)

Description

[Florian Bender]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:20.0) Gecko/20100101 Firefox/20.0
Build ID: 20130220104816

Steps to reproduce:

Visit Firefox Marketplace start page and scroll around. 


Actual results:

Scrolling is (sometimes) choppy.


Expected results:

Scrolling should be smooooth.

Comment 1

[Florian Bender]

This happens on a low-level 2012 MBA with 8Gb RAM und just a few programs opened, so this shouldn't be a resource or I/O problem. 

This may be a Fx issue or a Marketplace issue or both. This definitely should be improved.

Comment 2

[Florian Bender]

This issue seems to arise only when the mouse is hovering over the categories area. If the mouse is on either side of the categories area, scrolling is smooth (as far as I can tell). 

I'm scrolling using the gesture on the built-in touchpad, if this info is of any help.

Comment 3

[Florian Bender]

See this answer for a likely cause: 

(In reply to Jeff Muizelaar [:jrmuizel] from bug 846459 comment #11)
> I was actually a little bit wrong. It seems like the actual cause is the
> grain image.
> What's happening is we take the 200x200 image tile it on to a 3040x2560
> surface and scale that down to the particular category tile.
> 
> If you remove the background-size: 10px 10px from mkt/grain.png everything
> draws much faster.

Comment 4

[Christopher Van Wiemeersch [:cvan]]

(In reply to Florian Bender from comment #3)
> See this answer for a likely cause: 
> 
> (In reply to Jeff Muizelaar [:jrmuizel] from bug 846459 comment #11)
> > I was actually a little bit wrong. It seems like the actual cause is the
> > grain image.
> > What's happening is we take the 200x200 image tile it on to a 3040x2560
> > surface and scale that down to the particular category tile.
> > 
> > If you remove the background-size: 10px 10px from mkt/grain.png everything
> > draws much faster.

This has been fixed on -dev and will land tomorrow. The 10px was a typo, it should've been 100px (for retina). There should be a Firefox bug filed if there is not already, as this performs fine in Chrome.

Comment 5

[Florian Bender]

This is probably Bug 732150, no?

Comment 6

[Christopher Van Wiemeersch [:cvan]]

(In reply to Florian Bender from comment #5)
> This is probably Bug 732150, no?

I think that bug accurately describes the same issue, yes.