- From: Ian Hickson <ian@hixie.ch>
- Date: Wed, 16 Jan 2008 03:00:46 +0000 (UTC)
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. `._.-(,_..'--(,_..'`-.;.'
Received on Tuesday, 15 January 2008 19:00:46 UTC