Adding polyfills for MouseEvent.offsetX and MouseEvent.offsetY so they work on FF.

Adding polyfills for MouseEvent.offsetX and MouseEvent.offsetY so they work on FF.


BUG=1087
Committed: https://code.google.com/p/dart/source/detail?r=11411

[vsm, 2012-08-27 17:34:07]

lgtm.  Do you have a test for this you can also check in?

[Jacob, 2012-08-27 19:18:51]

https://chromiumcodereview.appspot.com/10867073/diff/1/lib/dom/templates/html...
File lib/dom/templates/html/dart2js/impl_MouseEvent.darttemplate (right):

https://chromiumcodereview.appspot.com/10867073/diff/1/lib/dom/templates/html...
lib/dom/templates/html/dart2js/impl_MouseEvent.darttemplate:18: return
this.clientX - this.target.$dom_getBoundingClientRect().left;
perhaps cache this value as an expando? would be odd if on firefox offsetX
changed as you moved an element but on WebKit it didn't.
Other notes: is this calculation right? If an element has a large border or uses
WebKit transforms (e.g. Rotate3D) won't this give an odd result?
I'd suggest adding a comment to the interface warning about the limitations of
using offsetX.

[blois, 2012-08-27 20:12:16]

I flushed out an existing unit test to add offsetX/Y checks and added
documentation for these properties.

https://chromiumcodereview.appspot.com/10867073/diff/1/lib/dom/templates/html...
File lib/dom/templates/html/dart2js/impl_MouseEvent.darttemplate (right):

https://chromiumcodereview.appspot.com/10867073/diff/1/lib/dom/templates/html...
lib/dom/templates/html/dart2js/impl_MouseEvent.darttemplate:18: return
this.clientX - this.target.$dom_getBoundingClientRect().left;
Caching only really helps if it's set in the constructor, but doing so would
involve unwanted performance overhead. Rather, I'm adding documentation noting
the potential platform limitations.

On 2012/08/27 19:18:51, Jacob wrote:
> perhaps cache this value as an expando? would be odd if on firefox offsetX
> changed as you moved an element but on WebKit it didn't.
> Other notes: is this calculation right? If an element has a large border or
uses
> WebKit transforms (e.g. Rotate3D) won't this give an odd result?
> I'd suggest adding a comment to the interface warning about the limitations of
> using offsetX.

[Jacob, 2012-08-27 20:14:20]

lgtm