On Fri, Feb 1, 2013 at 8:42 AM, Simon Sapin <simon.sapin@kozea.fr> wrote: > Le 01/02/2013 17:34, Rik Cabanier a écrit : > >> >> >> On Fri, Feb 1, 2013 at 6:50 AM, Brad Kemper <brad.kemper@gmail.com >> <mailto:brad.kemper@gmail.com>**> wrote: >> >> On Jan 31, 2013, at 11:18 PM, Simon Fraser <smfr@me.com >> <mailto:smfr@me.com>> wrote: >> >> > We rely on Core Graphics to render gradients on Mac, and that >> can't do pre-multiplied. That's the main reason why gradients don't >> match transitions. >> >> If I understand correctly, this means that if an author wants a nice >> clean-looking 3-stop gradient that goes from yellow to transparent >> to blue, he will have to use two same-position transparent color >> stops, so that it is actually yellow to transparent-yellow, and then >> transparent-blue to blue. Couldn't WebKit just perform this extra >> conversion step for us before passing it on to Core Graphics? >> >> >> This is why I would do under the hood. >> > > Is this equivalent to pre-multiplied with transparent being always > rgba(0,0,0,0)? > > For going to 'transparent', yes, you would get the same result. There will be a different though when you go from green to transparent red. With a premultiplied gradient, the color in the middle is green with 50% alpha. (The red is ignored) With a non-premultiplied gradient, the color in the middle is rgba(127, 127, 0, .5)
Received on Friday, 1 February 2013 18:36:17 UTC