[whatwg] [canvas] inner shadows

Ian Hickson ian at hixie.ch
Sat Nov 24 08:36:34 PST 2012

On Sat, 24 Nov 2012, Rik Cabanier wrote:
> > >
> > > How about the strokes?
> >
> > The example in the OP didn't have them, but you'd have to include them 
> > in the fill area. With the new Path objects, you'd just use 
> > addPathByStrokingPath(), which would be relatively simple.
> Unfortunately the winding rules will mess up your shape. (non-zero 
> winding)
> Take for instance a stroked circle. The stroke which is added with 
> addPathByStrokingPath will always create a hole so you end up with a 
> donut instead of just a slightly larger circle.


> > So long as they don't overlap, that's not generally a problem. But 
> > sure, for some complex shapes you'd need some new feature or other, 
> > whether it's in shadows or path construction or elsewhere.

In the case of a circle, if you wanted to draw the inner shadow over the 
stroke and the fill, you'd have to create the path as just a fill with the 
radius increased by half the line width.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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