[whatwg] Canvas Proposal: aliasClipping property

Charles Pritchard chuck at jumis.com
Sat Oct 3 16:10:53 PDT 2009

There have been a few discussions about anti-aliasing / aliasing in 
Canvas implementations.
Of those I read through, the conflict remains.

In some implementations: when drawImage is used along with a clipping path,
feathering is applied. This shows up in several projective 
transformation demos
contrasting Firefox with Chrome.

I believe that if we allow a toggle for this setting, we can bring some 
to the two systems.

Enumerate two aliasClipping values : "aliased", "feathered"

I consider "anti-aliased" to confusing, I think "feathered" is a better 


interface CanvasRenderingContext2D {
     attribute DOMString aliasClipping; // default "feathered"

context . aliasClipping [ = value ]

     Returns the current aliasing of the clipping region, as applied to 
rendering operations.

     Can be set, to change the aliasing value.

     If any of the arguments are not implemented, throws a 

CanvasRenderingContext2D.prototype.defineSetter('aliasClipping') { throw 

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