678449 - white text on dark background draws differently compared to IE9 with DirectWrite

Status: NEW

(Core :: Graphics: Text, defect)

Description

[John Daggett (:jtd)]

Steps using trunk build

1a. Set 'gfx.font_rendering.cleartype_params.force_gdi_classic_max_size' to 0
1b. Restart browser
2. Click on URL

==> Text in the footer at the bottom (under "Our Other Media Sites") appears very light

3. Open IE9 and use the same URL for comparision

Result: the white text on a dark background in the footer is much lighter in FF trunk than in IE9

Comment 1

[John Daggett (:jtd)]

I suspect this has something to do with the background being used, if you remove the background image on the body then the text rendering is the same as IE9.  In case this is some form of layer system problem, I'm going to leave this open until I have a chance to dig a little deeper.

Comment 2

[Alex]

I think this is the same as Bug 626293. It's not just the footer with the wrong rendering, the entire page is suffering from it.

Comment 3

[John Daggett (:jtd)]

(In reply to Alex from comment #2)
> I think this is the same as Bug 626293. It's not just the footer with the
> wrong rendering, the entire page is suffering from it.

As I said in comment 1, this appears to have something to do with the way the background is rendered, which would affect all elements on the page.

It's definitely not bug 626293, that's basically a complaint about rainbow patterns in ClearType subpixel antialiasing.

Comment 4

[Jim Battle]

Attachment: small screen capture showing the problem

John filed this after I mentioned it here:
http://blog.mozilla.com/nattokirai/2011/08/11/directwrite-text-rendering-in-firefox-6/comment-page-1/#comment-717

Oddly, the problem went away for a week or two, but it has come back again.  I'm seeing it on FF6 still, and not other browsers.  I've attached a small image from velonews showing the problem with rainbow-colored text.

If it matters, I'm running 64b Win 7 SP1, with an ATI Radeon HD 5450 display adapter.