742754 - PNG rendering ( text anti-alias edges use case ) looks bad

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[mgalli]

Attachment: cartao.png open with Firefox 10 and Firefox 11 and see the text closer

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:11.0) Gecko/20100101 Firefox/11.0
Build ID: 20120312181643

Steps to reproduce:

Opened a PNG image with Firefox 10 and Firefox 11


Actual results:

Firefox 11 showed the edges of the text with a poor rendering


Expected results:

Fine rendering.

Comment 1

[mgalli]

Attachment: Comparisons with desktop screencapture ( good antialias is Firefox 10 )

Comment 2

[Marcelo Araldi]

Really, there is a difference.
I've compared it using Fx 10 and 11 on Windows 7 64-bits.

Comment 3

[Marcelo Araldi]

Attachment: Comparison between Firefox 10 and 11 using Windows Seven 64 bits.

Comment 4

[Clauber Stipkovic [:cstipkovic]]

Attachment: Comparison between Firefox 10 and 11 using Ubuntu Linux 11.10 64 bits.

Comment 5

[Clauber Stipkovic [:cstipkovic]]

The difference is happening on Linux Firefox for Linux too!

Comment 6

[Clauber Stipkovic [:cstipkovic]]

The difference is happening on Firefox for Linux too!

Comment 7

[mjh563]

This is another problem caused by bug 376997.

The letters have some transparent pixels around the edges, which means the background colour shows through. Starting in Firefox 11, images are shown against a dark background instead of a white background, which means the edge pixels are dark instead of white. That's what's causing the problem.

Comment 8

[mjh563]

Attachment: red background

This shows how it appears when viewed against a red background. You can see which pixels are affected by the background colour.

Comment 9

[mjh563]

The best way to fix it would be to just remove the transparency from the image.

Comment 10

[Guilherme Lima]

I think this issue is fixed, at least on Firefox Beta and Nightly, Windows 7 and HWA doesn't make a difference.

Comment 11

[Wayne Mery (:wsmwk)]

(In reply to Guilherme Lima from comment #10)
> I think this issue is fixed, at least on Firefox Beta and Nightly, Windows 7
> and HWA doesn't make a difference.

do you agree?

Comment 12

[mjh563]

(In reply to Wayne Mery (:wsmwk) from comment #11)
> (In reply to Guilherme Lima from comment #10)
> > I think this issue is fixed, at least on Firefox Beta and Nightly, Windows 7
> > and HWA doesn't make a difference.
> 
> do you agree?

Yes, I guess this got fixed in Firefox 15 by bug 754133.