- From: Dirk Schulze <dschulze@adobe.com>
- Date: Thu, 6 Mar 2014 22:15:48 +0000
- To: fantasai <fantasai.lists@inkedblade.net>
- CC: "www-style@w3.org" <www-style@w3.org>
I prepared a draft of CSS Masking with multiple layers and the mask-composite property. I believe that it is ready for an initial review[1]. Greetings, Dirk [1] http://dirkschulze.github.io/specs/css-masking-1/ On Mar 5, 2014, at 11:19 PM, Dirk Schulze <dschulze@adobe.com> wrote: > During the todays CSS WG call, there has been a discussion about mask-composite[1]. It was asked to align masking and background as close together as possible in general. > > More specifically, it was asked to view the proposal for mask-composite in the light of background. Similar to background-blend-mode there could be a property background-composite that allows the different compositing operators defined by CSS Compositing[2]. > > The mask-composite and background-composite properties are both implemented prefixed in WebKit and Blink based browsers. It is possible to experiment with these implementations. > > A problem that came up while implementing background-blend-mode is that many graphic libraries do not allow setting a compositing operator other than source-over together with a blend-mode other than normal. WebKit won’t apply blending if you specify a compositing operator other than source-over IIRC. > > I will add a use case for compositing of background layers soon. The use case I had was compositing an image with a background color and continue using the result by blending if with another layer. > > Greetings, > Dirk > > [1] http://dirkschulze.github.io/specs/css-masking-1/#the-mask-composite > [2] http://www.w3.org/TR/compositing-1/#canvascompositingandblending > > On Mar 5, 2014, at 9:49 PM, Dirk Schulze <dschulze@adobe.com> wrote: > >> >> On Mar 5, 2014, at 6:02 PM, fantasai <fantasai.lists@inkedblade.net> wrote: >> >>> On 03/05/2014 03:15 AM, Dirk Schulze wrote: >>>> >>>>> I vaguely remember the problem being something about choosing between >>>>> - each layer acts individually as a mask over all the layers+content >>>>> before it >>>>> vs. >>>>> - composite all the mask images, then use that as a mask >>>>> and then the possibility of grouping certain combinations of images >>>>> rather than all or none. Does your proposal address that in a reasonable >>>>> way? >>>> >>>> I believe so. Not only that, it provides much more control over the content, >>>> many people familiar with globalCompositeOperators from HTML canvas will >>>> appreciate having the same capabilities. >>>> >>>> The two modes you mention can be archived with source-over (draw layers >>>> on top of each other and mask together) and destination-in (mask each >>>> layer with the the next layer and then mask content with the result). >>> >>> Can you give an example that would accomplish the two behaviors above? >>> Do I need to be careful with the operator assigned to the last image, >>> for example? >> >> I added 3 images to the compositing examples[1]. It hope it make things more clear. Please take a look at the examples. >> >> Greetings, >> Dirk >> >> [1] http://dirkschulze.github.io/specs/css-masking-1/#the-mask-composite >> >>> >>> ~fantasai > >
Received on Thursday, 6 March 2014 22:16:38 UTC