- From: Philip Taylor <excors+whatwg@gmail.com>
- Date: Mon, 21 May 2007 02:22:03 +0100
On 20/05/07, L. David Baron <dbaron at dbaron.org> wrote: > I thought what Safari does is basically "lighter", but with the > color components inverted (where inverting is CX = 1-CX, or cX = aX > - cX), so that it comes out to: > > aO = min(1, aA + aB) > cO = aO - min(1, aA - cA + aB - cB) Aha, that does indeed match what Safari does exactly - I thought I'd tried that before, but must have done something wrong. > Hrm. I thought lighter was confusingly *like* darker, in that they > act exactly the same when the alphas add to less than or equal to 1. > (I think that's true for plus (a.k.a. lighter), Cocoa's darker, and > for saturate.) I thought it may be more common to have alpha=1 on source and destination - then you get red lighter green = yellow red saturate green = green red darker green = black so they don't seem that much alike, except when looking in the range where they do seem alike. But I have no idea how people tend to really use these things in practice, and whether they give similar results in those cases... > > -David > -- Philip Taylor excors at gmail.com
Received on Sunday, 20 May 2007 18:22:03 UTC