[fxtf-drafts] [css-masking-1] Clarify how mask-mode & mask-composite behave with layered mask images

AmeliaBR has just created a new issue for https://github.com/w3c/fxtf-drafts:

== [css-masking-1] Clarify how mask-mode & mask-composite behave with layered mask images ==
When it comes to layering multiple images in the `mask-` properties, the [CSS Masking module](https://drafts.fxtf.org/css-masking-1/#layering) mostly references CSS backgrounds.  That would mean that if any of the longhand properties consisted of a single value, it would be repeated for every image layer.

However, `mask-mode` and `mask-composite` properties don't have a counterpart in CSS backgrounds.  I would assume they would behave the same way, but the good folks who implemented masks in Firefox (Hooray for them!) seem to have not thought of that.  I have [filed a bug on them](https://bugzilla.mozilla.org/show_bug.cgi?id=1366434), but I thought the spec itself could use some extra clarification.

PS, [Test case on CodePen](https://codepen.io/AmeliaBR/pen/0698690e9eadcd708a9709b73ebb7d89/?editors=1100).  

Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/171 using your GitHub account

Received on Saturday, 20 May 2017 03:13:34 UTC