On Wed, 21 Mar 2012 09:41:58 -0700, Brion Vibber <[email protected]> wrote:
On Mar 21, 2012 4:40 AM, "Bergi" <[email protected]> wrote:
Brion Vibber schrieb:
Ooh! We may be able to handle this like the js/nojs styles.
Have a bit of JS on startup check for svg support and add a class to
the
HTML root element. Then we just need .svg .foo {} entries with the svg
background overrides.
Wouldn't that mean loading the png thumbnails, and then onDomReady
replacing them with svgs? I think we really should deliver an output that
lets the browser choose one of them, not one plus maybe a second to load.
This'd handle CSS background images, and doesn't have to wait for dom
ready
because it operates on the document's root element - always available.
I'm thinking something like this in mediawiki.page.startup.js:
// Client profile classes for <html>
// Allows for easy hiding/showing of JS or no-JS-specific UI elements
var $html = $( 'html' )
.addClass('client-js' )
.removeClass( 'client-nojs' );
// Check for client SVG support, since we can't reliably use multiple
// images as fallbacks for SVG -> PNG in CSS
try {
var svg = document.createElementNS( 'http://www.w3.org/2000/svg',
'svg' );
if (typeof svg.createSVGPoint == 'function') {
$html.addClass('client-svg');
}
} catch (e) {
// can't even create SVG element!
}
Should also double-check the assumption that supporting SVG this way
means
supporting SVG in CSS background images. (Within modern browsers
supporting
jQuery, it *should* but you never know)
Things in <img>s still need a reliable fallback that
Still pondering best way to handle direct <img>s... ideally we'd use
<object> but this'll probably trigger missing plugin warnings on some
browsers, while we want to be nice and silent!
I actually tried that once to see if it was possible to have jpeg2000 and
a fallback image in the browsers that don't support it.
It doesn't work. Forget the warnings, it just doesn't work.
'Crazy' methods might include something like this inline:
<script>document.write('<' + 'img data-svg-src="//foo.svg"
data-png-src="//foo.png">')</script>
<noscript><img src="//foo.png"></noscript>
and a DOM-ready-time fixup to set the 'src'. This feels ugly though, and
delays start of image loading a bit (though we'd probably be loading
styles
mostly first?)
-- brion
--
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]
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