[whatwg] Still more comments and questions on Web Apps 1.0
ian at hixie.ch
Tue Jan 15 19:00:46 PST 2008
On Sun, 10 Jun 2007, Maciej Stachowiak wrote:
> On Jun 8, 2007, at 6:05 PM, Ian Hickson wrote:
> > > I am not an expert here, but IIRC, the underlying PDF/Quartz imaging
> > > model does not allow general xoring. I think it is important to
> > > ensure that canvas can be implemented on top a Quartz 2D drawing
> > > context on OS X without breaking hardware acceleration or PDF
> > > output.
> > I can drop 'xor', I guess...
> PDF can't actually do the other porter-duff operators either (except
> SrcOver). Instead it has a different concept of "blend modes" which are
> supposedly more general but can't actually synthesize the porter-duff
> operators. However, on OS X the 'xor' operator will be supported at
> least as well on any given graphics context as, say, SrcAtop or
> DestAtop. In practice what happens on graphics contexts that can't
> natively support the operator is that a bitmap is generated.
> I would recommend against dropping XOR.
Ok, 'xor' remains.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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