651662 - Clicking "show obsolete" in Bugzilla changes (disables?) ligatures

Status: RESOLVED INVALID

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

Description

[Justin Lebar (not reading bugmail)]

STR:

 * Install Bugzilla Tweaks add-on
 * Visit https://bugzilla.mozilla.org/show_bug.cgi?id=647028
 * Notice that obsolete patches are shown, even though the "show obsolete" link is present.  Presumably this is the extension's doing.
 * Click "show obsolete".
 * Notice that the "ff" in "diff" changes slightly.

The kerning is a little less tight, so I think the ligature is disabled when you click "show obsolete" and re-enabled when you hide obsolete.

I have no idea if this is a bug in the extension or in our font handling, although it seems strange that an extension could accidentally cause this behavior.

Comment 1

[(no longer active)]

Firstly, I couldn't reproduce this on Mac OS X 10.6.

This is what the Bugzilla Tweaks extension does to rows in the attachments table marked as obsolete: <https://bitbucket.org/ehsan/bugzilla-tweaks/src/fd9b459c59f9/data/js/bug-page-mod.js#cl-653>  Setting that class name causes the row to have {display: table-row !important}. <https://bitbucket.org/ehsan/bugzilla-tweaks/src/fd9b459c59f9/data/js/bug-page-mod.js#cl-92>

The functionality of the Show Obsolete link is not modified from the extension.

Comment 2

[Justin Lebar (not reading bugmail)]

I'm also on 10.6.  I just reproduce with a clean profile.  It's hard to see in side-by-side screenshots, so I'll post an animation.

Comment 3

[Justin Lebar (not reading bugmail)]

Attachment: Screenshot 1

Comment 4

[Justin Lebar (not reading bugmail)]

Attachment: Screenshot 2

Comment 5

[Justin Lebar (not reading bugmail)]

Well, no animation, but the two screenshots are cropped the same, so you should be able to switch between them in tabs and see the difference in the "ff" characters.

Comment 6

[Justin Lebar (not reading bugmail)]

Hm.  I'd checked that this only happened with Bugzilla Tweaks, but I think I was wrong.  It's actually hard to tell, because the table width may change when you show obsolete without Bugzilla Tweaks.  This changes the alignment of the letters, which can effect this change.

That said, when you have Bugzilla Tweaks installed, the table's width *doesn't* change, and yet the rendered text does.

Comment 7

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Could be a subpixel difference in positions changing the font rasterization.

Comment 8

[Justin Lebar (not reading bugmail)]

(In reply to comment #7)
> Could be a subpixel difference in positions changing the font rasterization.

Indeed, that's kind of what it looks like.  (This is now more difficult to reproduce under the new Bugzilla.)

Is it a bug that clicking that link, which appears to do nothing other than change "Show obsolete" to "Hide obsolete", changes the location of "diff"?  It seems like that shouldn't happen, but maybe we don't care.

Comment 9

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

No, since the text "jonas: review+" is wider than the text "paul: review+", so the intrinsic width of the table is wider with the obsolete patches shown, which reduces the amount of extra space to distribute among the table columns... at least without the bugzilla tweaks addon.  I'm not sure what it looks like with it.

Comment 10

[Justin Lebar (not reading bugmail)]

> No, since the text "jonas: review+" is wider than the text "paul: review+", so
> the intrinsic width of the table is wider with the obsolete patches shown,
> which reduces the amount of extra space to distribute among the table
> columns.

Ah, I see.

Okay!  Let's close this.  Sorry for the noise.