795072 - Support multiple downscale requests

Status: RESOLVED DUPLICATE of bug 1060200

(Core :: Graphics: ImageLib, defect)

Description

[Joe Drew (not getting mail)]

Attachment: Support multiple scales

Bug 486918 introduces a high-quality downscaler, but only supports 1 scale request at a time. It should support many; Jeff suggests 16, which is as reasonable a number as any.

Comment 1

[Robert Lickenbrock [:rclick]]

Comment on attachment 665590 [details] [diff] [review]
Support multiple scales

Review of attachment 665590 [details] [diff] [review]:
-----------------------------------------------------------------

::: image/src/RasterImage.cpp
@@ +2796,5 @@
> +
> +  // We remove from the back and insert to the front.
> +  ScaleRequest* old = mScaleRequests.back();
> +  mScaleRequests.pop_back();
> +  delete old;

Is it possible for the old request to still be in the middle of scaling at this point? If it is, I'm concerned that this may cause use-after-free.

Comment 2

[Joe Drew (not getting mail)]

Comment on attachment 665590 [details] [diff] [review]
Support multiple scales

I want to rework this somewhat.

Comment 5

[fireattack [:fireattack]]

OK now this bug is abandoned by its reporter, and we still have this issue.
(Also check https://bug849240.bugzilla.mozilla.org/attachment.cgi?id=722794)

Comment 6

[freezindevil]

Bug occasionally affects pages with one instance of the image on each page but have been loaded into cache before. Open links in that order.
https://taigaak.org/dump/imgscale3/
https://taigaak.org/dump/imgscale4/
https://taigaak.org/dump/imgscale2/

Comment 9

[mgreter]

Hi all

I'm the reporter of the previous (duplicate) Bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=979352

I've added a small example in that report, but mainly wanted to ask a few questions and present a possible workaround (that at leasts seem to work for my case). Am I right, that the "1 scale request at a time" limit is only valid for a single image instance? If that's correct my findings seem logical and adding a random/pseudo query string to the image request should work around this issue (my tests seem to point in that direction).

Of course this is not 100% optimal as it means it would download the images multiple times. In a (very few?) cases it might not even be possible to alter/append to the query string. But in my case I luckily can code this via jQuery and images are only static resources. It would IMO allow to write a jQuery plugin that would do this for all needed images automatically (and only for firefox).

Maybe someone with more insight/knowledge could confirm that? So we would at least have a documented workaround?

Hope this is usefull for some people!

Comment 10

[fireattack [:fireattack]]

Any updates on this bug? IMO it's a crucial one which affected the user experience of image-heavy sites a lot.

Comment 11

[Elbart]

There was and currently is a lot of activity regarding changing scaling-stuff for images.
Will the use-cases describe in here, especially comment #5, be covered by these changes?

Comment 12

[Seth Fowler [:seth] [:s2h]]

Elbart, this is fixed 100% by bug 1060200. (Indeed, perhaps I should've posted that patch in this bug, but it's too late to rearrange things now.)

I'm going to dupe this against bug 1060200.