1546123 - [about:addons] Fix size detection for preview images

Status: VERIFIED FIXED

(Toolkit :: Add-ons Manager, defect, P1)

Description

[Rob Wu [:robwu]]

The size for theme preview images is computed using getComputedStyle: https://searchfox.org/mozilla-central/rev/d80f0a570736dce76a2eb184fb65517462089e8a/toolkit/mozapps/extensions/content/aboutaddons.js#410

But because the image is initially empty (and possibly not even part of the DOM yet!), the resulting size is 0, so the logic will fall back to the first screenshot in the list.

This can result in selecting the incorrect image for theme previews.

Note that the cards have a fixed width, so the fix could be as simple as using a fixed number (or deriving it from a CSS variable).

There have been some attempts to change the size, from 680 to 720, but we're apparently back at 680 now:

• https://github.com/mozilla/addons-frontend/issues/7553
• https://github.com/mozilla/addons-server/issues/9419

Comment 1

[Rob Wu [:robwu]]

Attachment: Bug 1546123 - Correct size calculation of theme previews

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c372247f4432
Correct size calculation of theme previews r=mstriemer

Comment 3

[Andreea Pavel [:apavel]]

Hi Rob, i mentioned https://bugzilla.mozilla.org/show_bug.cgi?id=1546248#c11 that this got backed out, not sure if you noticed.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/134e12b67bba
Correct size calculation of theme previews r=mstriemer

Comment 5

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/134e12b67bba

Comment 6

[CosminB]

Attachment: Bug1546123.png

This issue is verified as fixed on Firefox 69.0a1 (20190521094447) and Firefox 68.0b3 (20190520131124) under Win 7 64-bit and Mac OS X 10.14.1.

Please see the attached screenshot.