Re: [Tails-dev] review and merge feature/6999-compress-png

intrigeri:
> sajolida wrote (01 Mar 2015 18:00:02 GMT) :
>> Thanks to the investigation of naar on PNG compression, I'm
>> submitting a branch that compresses the PNG images we ship from the
>> website in our ISO
>
>> [...] and adapt the release process accordingly.
>
> That part seems quite problematic to me, as "The compression seems to
> be deterministic. Running it several times produces the same binaries"
> (found in the commit message that introduces this find command) is
> apparently not entirely correct: I've just run that find command, and
> it changed no less that 120 image files. If I commit the result as
> documented, I bet our .git will grow by ~3% (~2M), just like fetching
> your branch did here.
>
> So, it may lead to regular, substantial increases in the size of our
> .git directory. Let's please avoid that :)

Too bad!

> It might be that this non-determinism happens only because I'm running
> different versions of optipng and advdef (and then, will happen "only"
> when we switch RMs back and forth, or when the RM upgrade their
> system). It might be that this would also happen with the very same
> version of the tools. It could be arch-dependent, and a RM running an
> amd64 system might get different files than someone running (i386)
> Tails.
>
> => If we want to include this command, this requires quite some more
> testing to evaluate what its potential painful impact it. Or, let's
> just revert commit 488af40 and merge the branch?
>
> Another option would be to have ikiwiki recompress these images when
> building the wiki. This would be a bit costly, so likely not suitable
> for local builds, but just fine on our production website I guess.
> Is there any plugin that does something like that? If not, it should
> be relatively trivial to write.

Maybe we need to make it more clear what's the objective. To me the
objective is to reduce the impact of PNG images on the size of our ISO
images. I don't care so much about online visits to the website, seeing
that this only bring 15% compression overall.

If we agree on that, then maybe that could be hooked in the ISO build
process (and not in the wiki build process). Could that go in auto/build
right after build-wiki? So that people doing local builds of the wiki in
Tails (translators and doc writers) are not affected given that optipng
and advcompress are not in Tails.

But then, how would that interfere with IUKs? Would non-deterministic
builds of those images always end up in IUKs? But I guess that this does
not depend on whether this is done at ISO or wiki build time...

If we agree on this, then I'm very sorry to have polluted the Git repo
with 2MB of compressed binaries right after you cleaned it...