814804 - "h" letters in the SVG Wow "Text Effects" demo have an extra spike

Status: REOPENED

(Core :: Graphics, defect, P3)

Description

[Laszlo Mocsar]

User Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/17.0 Firefox/17.0
Build ID: 20121119183901

Steps to reproduce:

Open URL: http://svg-wow.org/text-effects/text-effects.xhtml


Actual results:

Every "h" letter has an extra spike


Expected results:

"h" letters should have displayed normally

Comment 1

[Laszlo Mocsar]

This is a regression. Demo was working fine in FF 16.0.2, bug appeares in FF 17.0

Comment 2

[Matthias Versen [:Matti]]

Last good nightly: 2012-05-23
First bad nightly: 2012-05-24

Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=36e938e51481&tochan
ge=f43e8d300f21

Comment 3

[Matthias Versen [:Matti]]

The bug disappears if you either zoom the testcase or disable hwa

Comment 4

[Matthias Versen [:Matti]]

Last good nightly: 2012-05-21
First bad nightly: 2012-05-22

Pushlog:
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?startdate=2012-05-
21&enddate=2012-05-22

Bas Schouten checkins could have caused this

Comment 5

[Loic]

(In reply to Matthias Versen (Matti) from comment #3)
> The bug disappears if you either zoom the testcase or disable hwa

With HWA off, I'm still able to see it: http://i.imgur.com/PoyZm.png (FF20 on Win7)

Comment 6

[Laszlo Mocsar]

In FF 17.0.1 the "h" letters in the center are correctly displayed, but in the subtitles they are still wrong.

Comment 7

[Laszlo Mocsar]

I checked now and Internet Explorer 10.0.9 and Opera 12.16 browsers render the "h" letters this spiky way too. Are they using code from Firefox? Or could it be a bug in the demo? But then how can it be a regression?

Comment 8

[Matthias Versen [:Matti]]

I don't know about Opera but IE doesn't use any Firefox Code.

Comment 9

[u279076]

I'm not seeing an issue locally. Does this still reproduce for you?

Comment 10

[Laszlo Mocsar]

Yes, it still reproduces in FF 48.0.1.

Comment 11

[u279076]

(In reply to Laszlo Mocsar from comment #10)
> Yes, it still reproduces in FF 48.0.1.

Could you please attach a screenshot comparing the "broken" behaviour to the "normal" behaviour? I'm sorry but I'm just not seeing this locally.

Comment 12

[Loic]

(In reply to Anthony Hughes (:ashughes) [GFX][QA][Mentor] from comment #11)
> (In reply to Laszlo Mocsar from comment #10)
> > Yes, it still reproduces in FF 48.0.1.
> 
> Could you please attach a screenshot comparing the "broken" behaviour to the
> "normal" behaviour? I'm sorry but I'm just not seeing this locally.

See comment #5, there is a screenshot of the bad rendering (ascender of the letter "h").

Comment 13

[u279076]

(In reply to Loic from comment #12)
> See comment #5, there is a screenshot of the bad rendering (ascender of the
> letter "h").

I'm sorry, I don't see the bug in this screenshot. I reiterate that it would be extremely helpful to see a comparative screenshot (ie. something which clearly shows broken and known good behaviour side-by-side). Also, please attach the screenshot to this bug report -- it's bad practice to depend on a third-party service for historical artifacts.

Comment 14

[Loic]

Attachment: screenshot-FF48.jpg

Comment 15

[Gregory Pappas [:gregp]]

Unable to reproduce in current versions.

Comment 16

[Laszlo Mocsar]

Still present in FF 110.0.1 (64-bit).

Comment 17

[Jonathan Kew [:jfkthame]]

This is not really a Firefox bug, it's a flaw in the "GoodDogRegular" webfont being used, and/or in the DirectWrite rasterizer. Whether it manifests depends on the font size being used (i.e. the final device-pixel size, accounting for page zoom and system display resolution in addition to the nominal size specified by the page). On my Windows machine, I see it at 100% scaling and at 150%, but not at larger sizes; on the other hand, at smaller sizes such as 50% it becomes even worse.

(It's probably an artifact of the TrueType hinting on that glyph, but I haven't attempted to work through the instructions and figure out if there's a clear bug in the hints, or if DirectWrite is mishandling them somehow.)