[whatwg] isPointInPath v. set of pixels in canvas hit regions
ian at hixie.ch
Thu Jul 5 14:25:50 PDT 2012
On Thu, 5 Jul 2012, Edward O'Connor wrote:
> As things currently stand in the spec, implementations basically need to
> keep N+1 bitmaps per canvas, where N is the number of hit regions. I
> doubt any implementors would be enthusiastic to implement hit regions
> like this. From a WebKit perspective, we'd much prefer keeping a Path
> for each hit region, and then simply using isPointInPath for hit
> testing. This also implies that the current piggybacking of "Clear
> regions that cover the pixels" in clearRect() could go away. Yay! :)
You only need one bitmap to implement the hit testing.
(Or you can do it using paths, sure. The effect is the same, but it's
probably quicker to use a bitmap.)
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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