[whatwg] Supporting scrollTop and scrollLeft on the Canvas element
chuck at jumis.com
Sat Feb 4 10:21:32 PST 2012
On 2/4/12 12:30 AM, Anne van Kesteren wrote:
> On Tue, 31 Jan 2012 23:35:45 +0100, Charles Pritchard
> <chuck at jumis.com> wrote:
>> I'd like to see scrollTop and scrollLeft supported for the Canvas
>> element. They would simply fire an onscroll event on the element, and
>> do nothing else.
>> Many Canvas UIs use only one visible canvas layer, or otherwise, one
>> main canvas layer.
> That would require special casing <canvas> in
> http://dev.w3.org/csswg/cssom-view/#scroll-an-element which I'm not
> sure is a good idea. Why don't you just dispatch a synthetic scroll
Does the scroll event carry x/y information?
I agree, this is a special case for canvas -- the precedent set by
<input type=text> is that form controls may have separate scroll semantics.
My proposal is not thought-out all the way, but I'm hoping it can float.
The idea here is to enable scroll with limited height/width canvas layer
to work well.
This is going to be useful for context.scrollPathIntoView as well as
simply running Element.scrollIntoView on elements within the Canvas
Currently, the scroll* attributes in Canvas are read only and set to
zero. So, I think there is room to support them in the future.
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