[webkit-dev] Newbie question re: raw bitmaps

Alex Danilo alex at legrope.com
Wed Dec 22 16:44:07 PST 2010


Hi Eric,

	Well at least it's a nice exercise to explore the architecture for
me if nothing else.

	IANAL, so I hadn't even considered IP as an issue, but that makes sense.

	It would a lot nicer to suppport it natively rather than via NPAPI
or similar, since you can skew/scale/shear and animate these things in SVG.
Good for a number of applications.

	Has anyone tried to hook in OpenEXR? Perhaps that would be a better
candidate for high dynamic range images although I'm not sure about it's
performance characteristics for embedded devices. The license is far more
friendly IIRC.

Cheers,
Alex

--Original Message--:
>Platforms provide their own image decoders.  Some of them use the
>cross-platform image decoders checked into WebCore:
>http://trac.webkit.org/browser/trunk/WebCore/platform/image-decoders
>
>A quick skim of mozilla's bug on the subject:
>https://bugzilla.mozilla.org/show_bug.cgi?id=500500
>leads me to believe there is currently no patent-safe way to use JPEG-XR.
>
>The only platform which has JPEG-XR natively is Windows, however both
>Apple's Windows port and Chromium's windows port use the checked-in
>image decoders.
>
>I think WebKit is unlikely to support JPEG-XR any time soon.
>
>Without mozilla supporting it (or much content on the web using it)
>there is little reason to add support.
>
>-eric
>
>On Wed, Dec 22, 2010 at 4:28 PM, Alex Danilo <alex at legrope.com> wrote:
>> Hi All,
>>
>>        Sorry to post a newbie question.
>>
>>        My name's Alex Danilo, I've been doing some SVG stuff over the past
>> few years and now have spent the past few months looking into the SVG
>> implementation in WebKit.
>>
>>        What I'm tyring to do is add a new image format in the engine
>> as an exercise.
>>
>>        I am trying to add support for JPEG-XR (formerly HD-Photo) as
>> a new supported image format for the <image> element (and <img> in
>> HTML I guess too).
>>
>>        Looking at the ports, code etc. this all plumbs via the Image
>> class, BitmapImage class, etc.
>>
>>        For some ports, like CG I see that the decode is done lazily
>> and defers it to CG so that no intermediate bitmaps are generated.
>>
>>        For JPEG-XR, I will have to unpack the ARGB32 bitmap somewhere
>> in memory and do a GraphicsContext drawImage() call to paint it to
>> the canvas.
>>
>>        So my question is, is there any preferred or desirable method
>> to accomplish this? i.e. how should I structure the interface to the
>> Image class to make sure it works on all ports without creating
>> a dog's breakfast of it?
>>
>>        All tips and pointers greatly appreciated.
>>
>> Cheers,
>> Alex
>>
>>
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>> webkit-dev at lists.webkit.org
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>>
>
>
>



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