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Re: Image orientation for backgrounds

From: Liam R E Quin <liam@w3.org>
Date: Tue, 15 Apr 2014 15:08:46 -0400
Message-ID: <1397588926.17924.212.camel@slave.barefootcomputing.com>
To: Boris Zbarsky <bzbarsky@MIT.EDU>
Cc: www-style list <www-style@w3.org>
On Tue, 2014-04-15 at 14:28 -0400, Boris Zbarsky wrote:
> On 4/15/14 2:13 PM, Liam R E Quin wrote:
> > Wouldn't a good way for Web apps be to have a JavaScript interface to
> > EXIF metadata?
> That's not enough, unfortunately, because there is no way to specify a 
> rotation for just a background

Good point.

>  and if you process the JPEG image to 
> produce a rotated image (e.g. by painting to a canvas, getImageData, 
> etc) you end up with some quality loss during the reencode.

One can rotate a jpeg image losslessly if it's a multiple of 8 pixels
wide; otherwise, there will be the same losses regardless.

>   And if you 
> don't reencode you pay a pretty hefty memory price for keeping the 
> decompressed data in memory...
Naah, a 40 megapixel node is just like a couple of DOM nodes :-)

So, really what I'm hearing is you need a way to tell the browser
rotate/transform a background image, and a way to find out from the
image metadata if that's needed, right?

Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
Ankh: irc.sorcery.net irc.gnome.org freenode/#xml
Received on Tuesday, 15 April 2014 19:08:49 UTC

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