1260094 - Implement margin-box value support for mask-origin and mask-clip properties.

Status: RESOLVED WONTFIX

(Core :: Layout, defect)

Description

[Astley Chen (inactive)]

Per spec, need to support margin-box value parsing and computation and relevant rendering.

mask-origin: margin-box
https://www.w3.org/TR/css-masking-1/#valuedef-margin-box

mask-clip: margin-box
https://www.w3.org/TR/css-masking-1/#valuedef-margin-box0

Comment 1

[Daosheng Mu[:daoshengmu]]

Ref tests:
http://dsmu.me/css-masking/bug1260094/mask-clip-margin-box.html
http://dsmu.me/css-masking/bug1260094/mask-origin-margin-box.html

Using -webkit-mask-image can't get my mask image. Probably, it is not be supported...

Comment 2

[Astley Chen (inactive)]

(In reply to Daosheng Mu[:daoshengmu] from comment #1)
> Ref tests:
> http://dsmu.me/css-masking/bug1260094/mask-clip-margin-box.html
> http://dsmu.me/css-masking/bug1260094/mask-origin-margin-box.html
> 
> Using -webkit-mask-image can't get my mask image. Probably, it is not be
> supported...

In current implementation, mask-repeat initial value is set to repeat instead of no-repeat, this is why in your test cases the masking is not working as expected. You can refer to bug1258623 for more details.

Comment 3

[Daosheng Mu[:daoshengmu]]

Update the ref test to the new link, http://dsmu.me/css-masking/bug1260094/mask-clip_origin-margin-box.html.

I have confirmed -webkit-mask-image is not supported in FF 48, but Chrome and Safari are good.

Regarding to mask-origin and mask-clip, Chrome and Safari are only supported border-box, FF is still waiting for implementation.

Comment 4

[Daosheng Mu[:daoshengmu]]

Attachment: MozReview Request: Bug 1260094 - Implement mask-origin for margin-box support.

Review commit: https://reviewboard.mozilla.org/r/48301/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/48301/

Comment 5

[Daosheng Mu[:daoshengmu]]

In nsCSSRendering::GetImageLayerClip, the aClipState->mBGClipArea has been clipped without referring the background-clip attribute. So, when I change the clip rect, the image is shifted but the visible region is still like before. 

The bounds of nsDisplayBackgroundImage get from nsBackgroundLayerState.mFillArea. We need to make it handle background-clip attribute internally.

Comment 6

[David Baron :dbaron:]

(In reply to Daosheng Mu[:daoshengmu] from comment #3)
> Update the ref test to the new link,
> http://dsmu.me/css-masking/bug1260094/mask-clip_origin-margin-box.html.

This test seems to show that Chrome does NOT support -webkit-mask-origin: margin-box.  But I don't see how the test would do anything differently if -webkit-mask-clip: margin-box were supported.

(I'd also note that background-origin does not have a margin-box value.)

> Regarding to mask-origin and mask-clip, Chrome and Safari are only supported
> border-box, FF is still waiting for implementation.

I'm not quite sure what you mean here, but if Chrome and Safari don't support the margin-box value, then it might make more sense to ask for the spec not to include the value, rather than spending work on implementing it.  Do they support margin-box?

Comment 7

[Daosheng Mu[:daoshengmu]]

(In reply to David Baron [:dbaron] ⌚️UTC-7 (review requests must explain patch) from comment #6)
> (In reply to Daosheng Mu[:daoshengmu] from comment #3)
> > Update the ref test to the new link,
> > http://dsmu.me/css-masking/bug1260094/mask-clip_origin-margin-box.html.
> 
> This test seems to show that Chrome does NOT support -webkit-mask-origin:
> margin-box.  But I don't see how the test would do anything differently if
> -webkit-mask-clip: margin-box were supported.
> 
> (I'd also note that background-origin does not have a margin-box value.)
> 
> > Regarding to mask-origin and mask-clip, Chrome and Safari are only supported
> > border-box, FF is still waiting for implementation.
> 
> I'm not quite sure what you mean here, but if Chrome and Safari don't
> support the margin-box value, then it might make more sense to ask for the
> spec not to include the value, rather than spending work on implementing it.
> Do they support margin-box?

Indeed, Chrome and Safari don't support margin-box value on mask-origin and mask-clip. We should stop implementing this bug and ask for modifying the spec.

Comment 8

[David Baron :dbaron:]

Attachment: some clearer testcases

Comment 9

[David Baron :dbaron:]

I filed https://github.com/w3c/fxtf-drafts/issues/5 .