On Thu, Aug 6, 2009 at 1:47 PM, Joel Webber <[email protected]> wrote:

> On Thu, Aug 6, 2009 at 1:40 PM, Matt Mastracci <[email protected]>wrote:
>
>> +1  This works well for us and I'd love to remove the complexity from our
>> build process.  We've dropped the transparency loader for some time now and
>> it's solved a lot of our IE6 bugginess (including random hard browser
>> lockups!).
>>
>
> Excellent. That's as good an existence proof as I need.
>
> On 6-Aug-09, at 11:29 AM, Joel Webber wrote:
>>
>>
>> If we want to support IE6 fully (which I hate having to do, but it's hard
>> to argue with the fact that it still account for ~20% of the market,
>> depending upon whose stats you use), then I think this is basically the only
>> approach that will work. We all agree that the DirectX filter is far too
>> memory hungry, especially on the old machines that are often still running
>> IE6. Bundling images with disparate palettes into a single 8-bit image is
>> far too unpredictable, which seems pretty unacceptable to me. So I will
>> argue that we should, on IE6:
>> - Leave GIFs alone.
>>
>> - Turn PNGs with transparency into GIFs.
>>   - Open question: How should we clamp the [0, 255] alpha channel to [0,
>> 1]?
>>
>>
>> In our experience, every transparency clamping preset will result in
>> artifacts in IE6 for some subset of images.  To simplify things, I'd suggest
>> mapping alpha of 0 to transparent, and alpha of 1-255 -> opaque.  If the
>> developer needs more control, they can convert the image to a GIF by
>> hand.  Alternatively, it might be useful to allow a developer to specify a
>> fallback IE6-only image.
>>
>> For quantization of partially transparent PNG to GIF, I highly recommend
>> the algorithm behind this tool:
>> http://members.ozemail.com.au/~dekker/NEUQUANT.HTML  There's already a
>> Java version of the code available.
>>
>
> Looks like it's being used in javax.media.jai. If that's available to us
> reliably, then we should probably use it.
>
> Side note: God, I thought I would never have to think about this problem
> again after everybody finally dropped their old VGA cards, and we could at
> least just deal with 5-5-5 vs. 5-6-5 16-bit color modes in all our assembly
> code. Wait, did I just date myself pretty badly?
>

Side side note: Holy crap, I just realized that NeuQuant uses a Kohonen
network to iteratively converge on a palette. No wonder it works so much
better. But does it end up taking a really long time to converge? I'd hate
to make the build take forever because it's waiting on a neural network to
converge :)

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