[webkit-dev] Newbie question re: raw bitmaps
myutwo33 at gmail.com
Sun Jan 2 06:30:02 PST 2011
*I feel I should point out here, that as far as I understand there is no
particular patent issue with Jpeg-XR. Microsoft have included Jpeg-XR under
their community promise program which is a legal promise not to sue anyone
for using patents they own for implementing a Jpeg-XR codec. The issue
mentioned in the bugzilla entry is not a patent problem. The problem is with
the reference code that Microsoft released for implementing a Jpeg-XR codec.
The licencing of which states the code can only be used to create/decode
images conforming to the Jpeg-XR spec. This condition makes the code non GPL
compatible. There is nothing stopping anyone from creating a GPL compatible
Jpeg-XR codec from scratch though.*
On 22 December 2010 14:59, Eric Seide <eric at webkit.org> wrote:
> 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.
> On Wed, Dec 22, 2010 at 4:28 PM, Alex Danilo <alex at legrope.com <http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev>> 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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