935466 - Remove APNG

Status: RESOLVED WONTFIX

(Core :: Graphics: ImageLib, defect)

Description

[Greg K.]

APNG is not widely used on the Web, so it should be removed from ImageLib to save space.

Comment 1

[Glenn Randers-Pehrson]

It is used within Mozilla though.  I count 33 of them in mozilla-central.  The savings would probably be well under 10 kbytes, and some if not all of that would be lost from converting the nearly half-megabyte of apngs to gifs.

Comment 2

[Glenn Randers-Pehrson]

Measuring the effect on "size libxul.so": 8352 bytes saved (out of 66,050,873) by disabling APNG on a Ubuntu 12:04 platform.  That's a 0.0126 percent savings.

Comment 3

[Masatoshi Kimura [:emk]]

We should implement animated WebP first as a replacement.

Comment 4

[Max Stepin]

Is it really a good replacement? See:
http://littlesvr.ca/apng/gif_apng_webp.html

APNG usage on the Web is significant, just search on deviantart.com or tumblr.com or pixiv.net and you'll find thousands of them. That's a very low estimate for the whole Web, considering that APNG plugin for Chrome reports 50,000 users.

Comment 5

[ekerazha]

APNG is useless unless most web browsers (desktop and mobile) natively support it. Chrome, Chrome for Android (maybe Opera too, since it uses Blink) natively support animated WebP.

Because of political reasons, in 2058 we will still have JPEG, plain PNG and animated GIF.

Comment 6

[Masatoshi Kimura [:emk]]

APNG has a fallback for unsupported browsers. Animated WebP is definitely useless unless most web browsers natively support it (it will just show a broken icon). Blink is not the rendering engine for most web browsers yet, at least on desktop :)

Comment 7

[Zéfling]

Cool, no possibilities for animation with 16M colors and alpha layer... I use APNG (with JapngEditor), so I am against the removal.

It's really cool for this Kickstarter : http://www.kickstarter.com/projects/374397522/apngasm-foss-animated-png-tools-and-apng-standardi

Comment 8

[Elbart]

Mozilla wants to remove it, Apple adds it:
http://www.macrumors.com/2014/09/28/ios-8-safari-supports-animated-png-images/

Weird world.

Comment 9

[Gordon P. Hemsley [:GPHemsley]]

(In reply to Elbart from comment #8)
> Mozilla wants to remove it

The existence of a bug report on something does not imply its support within the greater Mozilla community. In fact, most of the discussion here has been against removing APNG.

Given its use within the Mozilla codebase, and now the addition of support in Safari, I would venture to guess that APNG will not be remove, and that this will be marked WONTFIX.

Comment 10

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Yeah, now that Apple has added APNG, it seems like we may have a chance to get Google to adopt it. So we shouldn't remove it yet.

Comment 11

[Jeff Muizelaar [:jrmuizel]]

The maintenance burden of APNG has been very low. The animation code is mostly shared with animated gifs. Unless Glenn plans on dropping support from libpng I don't anticipate an increase in this maintenance burden. Given that we use apng internally I don't see much to gain from dropping support especially now that Apple is shipping it.

Comment 12

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

What Jeff said.

Comment 13

[Mike Hommey [:glandium]]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #11)
> Unless Glenn plans on dropping support from libpng

FWIW, there's no APNG support in libpng proper, it's patched in our copy of it. However, the APNG support in webkit does rely on a vanilla libpng (and is kind of gross as a result)

Comment 14

[Jeff Muizelaar [:jrmuizel]]

(In reply to Mike Hommey [:glandium] from comment #13)
> (In reply to Jeff Muizelaar [:jrmuizel] from comment #11)
> > Unless Glenn plans on dropping support from libpng
> 
> FWIW, there's no APNG support in libpng proper, it's patched in our copy of
> it. However, the APNG support in webkit does rely on a vanilla libpng (and
> is kind of gross as a result)

Right, but Glenn maintains this patch and does the updating of libpng into Mozilla so it's essentially upstream from a maintenance point of view.

Comment 15

[Glenn Randers-Pehrson]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #14)
> (In reply to Mike Hommey [:glandium] from comment #13)
> > (In reply to Jeff Muizelaar [:jrmuizel] from comment #11)
...
> Right, but Glenn maintains this patch and does the updating of libpng into
> Mozilla so it's essentially upstream from a maintenance point of view.

Actually, Max Stepin maintains the patch, and I use it to maintain the
intree libpng.  It's exactly the same patch used by others to maintain
an external system libpng that mozilla can link with.

Comment 16

[Max Stepin]

(In reply to Mike Hommey [:glandium] from comment #13)
> FWIW, there's no APNG support in libpng proper, it's patched in our copy of
> it. However, the APNG support in webkit does rely on a vanilla libpng (and
> is kind of gross as a result)

I wouldn't call it gross :) just a bit hacky remuxing, nothing too complicated.
I'm fine with maintaining the patch, but for long-term maintenance it would be better to rely on vanilla libpng by keeping all APNG code outside of it.