[Sugar-devel] Web activity example that uses html5 canvas

[James Cameron]

On Mon, Apr 29, 2013 at 10:42:40PM -0300, Manuel Qui?ones wrote:
> 2013/4/29 James Cameron <quozl at laptop.org>:
> > On Mon, Apr 29, 2013 at 04:23:24PM -0300, Manuel Qui?ones wrote:
> >> And here a live demo:
> >>
> >> http://manuq.github.io/clockjs/activity.html
> >
> > Should this work if opened on Firefox 20.0 on Ubuntu 12.10?
> >
> > (It shows a clock face, but no arms.)
> 
> It is because of requestAnimationFrame.  To make it compatible with
> all current browsers , I could do:
> 
> var requestAnimationFrame = window.requestAnimationFrame ||
> window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame
> || window.msRequestAnimationFrame;
> 
> I certeanly dislike doing such things for compatibility :)  If we are
> targetting webkit for now, and webkit has the generic one, I suppose
> I'll go with that.  It is just time for the other browsers to get it.
> What do you think?

Tested also on an Android tablet with the Browser app, the javascript
console reported "Uncaught ReferenceError: requestAnimationFrame is
not defined".  So this is the same thing.

I think code that might be executed in the wrong environment should at
least say why it won't run, rather than fail silently.

Otherwise, add a condition when you publish a live demo: "intended to work in
${browser} only".  ;-)

> Here are links for the mozilla page of the feature, and w3 the specification:
> 
> https://developer.mozilla.org/en/docs/DOM/window.requestAnimationFrame
> http://www.w3.org/TR/animation-timing/#requestAnimationFrame

Thanks.

-- 
James Cameron
http://quozl.linux.org.au/