617869 - first-letter/617869-1.html reftest fails due to inconsistent baseline of font-size:200% first-letter

Status: NEW

(Core :: Layout: Text and Fonts, defect)

Description

[Karl Tomlinson (:karlt)]

+++ This bug was initially created as a clone of Bug #553981 +++

Changes to gfxPlatform::SetupClusterBoundaries in bug 553981 fixed layout/reftests/first-letter/329069-2.html with CoreText but not with Uniscribe (same issue as Bug 615445, I assume) or DWrite.

Comment 1

[Karl Tomlinson (:karlt)]

Attachment: WINNT 5.2 reftest failure

Windows Server 2003 doesn't have font support, but that's not really an excuse for getting the clusters wrong.

Comment 2

[Karl Tomlinson (:karlt)]

Attachment: WINNT 6.1 reftest failure

The failure with DWrite shaping is just a baseline position difference and so not related to shaping/fonts but first-letter implementation.
Add lang="ko" (to improve font-selection) and an additional (not-first-letter) character does not correct the difference.

Comment 3

[Karl Tomlinson (:karlt)]

The baseline difference is not there when font-size:200% is removed.

Comment 4

[Karl Tomlinson (:karlt)]

Attachment: separate first-letter font-size test

Comment 5

[Jonathan Kew [:jfkthame]]

(In reply to comment #1)
> Created attachment 496466 [details]
> WINNT 5.2 reftest failure
> 
> Windows Server 2003 doesn't have font support, but that's not really an excuse
> for getting the clusters wrong.

The patch in bug 615445 (attachment 496786 [details] [diff] [review]) should fix the cluster issue on Win2k3/XP. (It doesn't address the baseline discrepancy, though, so the test with font-size will still fail.)

Comment 6

[Cork]

Attachment: Crash test

I'm getting a ton of crashes from this checkin:
bp-2c5545a5-b271-4329-b41c-782f92101210
bp-b3f5708e-a1d4-469e-bf6c-250a42101210
bp-4a21b3a2-cb00-49cf-8794-7e2cf2101210
bp-80ae45d6-85e5-479c-9022-105a02101210

The regression range points right at this bug:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=9ab76fbcb6d7&tochange=11e328a49e0a

Linux x86_64 systems only as far as i can see

Comment 7

[Cork]

Gah sorry wrong bug...

Comment 8

[Karl Tomlinson (:karlt)]

(In reply to comment #1)
> Windows Server 2003 doesn't have font support, but that's not really an excuse
> for getting the clusters wrong.

I think CompressedGlyph::SetMissing should not be overwriting FLAG_NOT_CLUSTER_START:
http://hg.mozilla.org/mozilla-central/annotate/61361e67bfc4/gfx/thebes/gfxFont.h#l1786

Comment 9

[Karl Tomlinson (:karlt)]

> I think CompressedGlyph::SetMissing should not be overwriting
> FLAG_NOT_CLUSTER_START:

Spun off into Bug 618870.

Comment 10

[Karl Tomlinson (:karlt)]

Separated the font-size test, so we have a passing Hangul Jamo test on WINNT 6.1.
http://hg.mozilla.org/mozilla-central/rev/bac79600ed97

Comment 11

[Karl Tomlinson (:karlt)]

Attachment: WINNT 6.1 reftest failure

Failures are similar on WINNT 5.2 and Mac, suggesting this might be a layout bug and perhaps Linux/FreeType is just getting lucky.

Comment 12

[Gérard Talbot]

Test is:

https://dxr.mozilla.org/mozilla-central/source/layout/reftests/first-letter/617869-1.html

and then click the Raw link in the righthand side column


Reference file is:

https://dxr.mozilla.org/mozilla-central/source/layout/reftests/first-letter/617869-1-ref.html

and then click the Raw link in the righthand side column



When I try such test with Firefox 52.8.0 ESR (under Linux Debian 9.4, 64-bit), I get exactly the reference file.

WORKSFORME