425441 - Slightly-stretched images look worse than in Fx2 due to use of bilinear filtering

Status: RESOLVED WONTFIX

(Core :: Graphics, defect)

Description

[David Corley]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9pre) Gecko/2008032705 Minefield/3.0pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9pre) Gecko/2008032705 Minefield/3.0pre

The main graphic on the Winamp homepage is "blurred" when viewed with FX3. FX2 and IE do not show the same blurring.

Reproducible: Always

Steps to Reproduce:
1.Visit Winamp.com with FX3
2.Repeat with FX2
3.Repeat with IE6
Actual Results:  
Image (including text in the image) is blurry

Expected Results:  
Image should be sharp

Comment 1

[David Corley]

Attachment: Winamp main graphic rendered in FX3

Comment 2

[David Corley]

Attachment: Winamp main graphic as rendered in FX2 and IE6

Comment 3

[Radek 'sysKin' Czyz]

Bilinear filtering.

Image is 760x275 but it's scaled to 760x276. Such scaling can't possibly look good.

Comment 4

[David Corley]

Is it the fault of Winamp.com then, or is FX being overly aggressive in filtering it?
I see IE reports it's size (right-click -> properties) as 760x276 also.
I guess I should let the Winamp guys know either way. Does seem a bit strange to be stretching the image.

Comment 5

[Matthias Versen [:Matti]]

Does the image look better if you load only the image in a new tab/window ?

Comment 6

[David Corley]

Looks perfect. I've let the Winamp site guys know about this here:
http://forums.winamp.com/showthread.php?s=&threadid=289119

Comment 7

[David Corley]

I'm pretty sure this isn't a bug from what's been discussed. Anyone have any objections to me marking this as INVALID?

Comment 8

[Matthias Versen [:Matti]]

It looks better in FF2 and IE6, i move this to Thebes for image scaling.
They can decide if this is just invalid or if we can do that better.

Comment 9

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Can't have it both ways... either we do filtered scaling or we don't.  We maybe might could do some tricks where we drop down to nearest-neighbour filtering if the scaling factor is less than some small amount (e.g. scaled up by less than 2px and less than 10% of the total image size)... roc, what do you think?

Comment 10

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

I've seen a few off-by-one errors in the wild like this. We could try to work around it but I think we'd do the Web a service if we don't try to work around and try to get these sites fixed instead. They're not really serious problems for our users and fixing the image sizes will give a significant speedup for all Web users.

Comment 11

[David Corley]

Even though I'm only a user, I'm actually in agreement with Robert on the issue. In the case of Winamp, I think the cause of the issue is a typo (setting the height to 276 instead of 275) and should be corrected on their end. I've posted to their forum and send a PM to one of the more active forum admins to get them to fix the issue. It's the only site I've noticed the issue on.

Comment 12

[Radek 'sysKin' Czyz]

It is perhaps worth adding that nearest neighbour resizing is not a good solution to deal with this case either.

Nearest neighbour will duplicate a line in the middle to add the extra height. It is pure coincidence that middle line of this particular picture is all black, therefore doubling is invisible. If there was any text in the middle, it would be obvious.

There is no good fallback in case of very small zoom ratio (that I know of).

Comment 13

[keenanpepper]

"There is no good fallback in case of very small zoom ratio (that I know of)."

Well, if for some perverse reason you really needed an image to be scaled by a few pixels, and look just as sharp, you could use seam carving ( http://portal.acm.org/citation.cfm?id=1275808.1276390 ), but I guess that's out of the question here...

Comment 14

[Jim Mathies [:jimm]]

I'm going to go ahead and close this out. For what it's worth, winamp appears to have fixed their site.