- From: Dirk Schulze <dschulze@adobe.com>
- Date: Wed, 5 Mar 2014 22:19:39 +0000
- To: fantasai <fantasai.lists@inkedblade.net>
- CC: "www-style@w3.org" <www-style@w3.org>
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 Wednesday, 5 March 2014 22:20:29 UTC