[webkit-dev] optimising png files in LayoutTests - an experiment

[Jarred Nicholls]

On Wed, Jan 25, 2012 at 4:57 PM, Elliot Poger <epoger at google.com> wrote:

> In deciding whether to just let the PNGs get shrunk over time or to do a
> pass over all of them at once, I think we should decide what we are trying
> to optimize for.  (Download time for initial checkout of the webkit tree?


For git users, the history is there and so initial checkout is not really
going to change afaik.


>  Time for existing developers to update their trees?  Storage space in the
> repository?)
>
> I would think that, except for initial checkout of the webkit repository,
> the others would be optimized by lazily converting the files (waiting until
> we need to check in new baselines, instead of shrinking them all at once).
>
>
> On Wed, Jan 25, 2012 at 1:12 PM, Dirk Pranke <dpranke at chromium.org> wrote:
>
>> I like the idea. I'm not sure I agree w/ Adam that I'd roll the code
>> into DRT, insofar as I don't know how big it is and I would definitely
>> want the code shared across all of the DRT implementations. I'd
>> probably also do a pass over all of the existing PNGs at some point
>> rather than wait for them to be updated as necessary.
>>
>> -- Dirk
>>
>> On Tue, Jan 24, 2012 at 10:43 PM, Mike Lawther <mikelawther at chromium.org>
>> wrote:
>> > Hi guys,
>> >
>> > Just thought I'd share the results of an experiment I did in optimising
>> the
>> > png files in LayoutTests.
>> >
>> > I used a tool on Mac called ImageOptim (http://imageoptim.pornel.net/)
>> which
>> > tries a set of different png lossless optimising tools (like pngcrush -
>> I
>> > also downloaded and included PNGOUT). Note that this strips out some of
>> the
>> > stuff we need, like the hash, so if doing this for real we'd have to
>> watch
>> > out for that.
>> >
>> > My results were:
>> >
>> > Before:
>> > $ ls -laR LayoutTests/ | grep png$ | awk '{total = total + $5}END{print
>> > total}'
>> > 1220535840
>> >
>> > Test:
>> > $ find LayoutTests/ | grep png$ | xargs open -a ImageOptim.app
>> >
>> > After:
>> > $ ls -laR LayoutTests/ | grep png$ | awk '{total = total + $5}END{print
>> > total, 1220535840 - total}'
>> > 937198328 283337512
>> >
>> > So this has saved ~280MB (~23% of the original size).
>> >
>> > Based on this, it seems worthwhile to include a png optimiser somewhere
>> in
>> > the patch upload/submit toolchain, and also (separately) to optimise the
>> > existing pngs.
>> >
>> > Thoughts?
>> >
>> >     mike
>> >
>> >
>> > _______________________________________________
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>> > webkit-dev at lists.webkit.org
>> > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>> >
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>
>
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