[fxtf-drafts] [css-masking-1] Clarify effect of `mask-image: none` (#563)

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

== [css-masking-1] Clarify effect of `mask-image: none` ==
Although `mask-image: none` intuitively reads as not masking the element, it is somewhat unclear from the [spec text](https://drafts.fxtf.org/css-masking-1/#the-mask-image).

In a [previous version of the spec](https://www.w3.org/TR/2014/WD-css-masking-1-20140213/#the-mask-image),  it was explicitly stated that the element is not masked:
> A value of none counts as an image layer but does not mask the element.

However, in later versions this has been changed to the following:
> A value of none counts as a transparent black image layer.

This text by itself makes it seem like the element is made transparent, as masking by a transparent black image would have the same effect as setting `opacity: 0`. Only by reading [the Mask Image Rendering Model](https://drafts.fxtf.org/css-masking-1/#the-mask-image-rendering-model) you find out that masking is only applied when `mask-image` is other than `none`.


Could we clarify that a value of `none` does not mask the element, either by adding a note or adding it to the spec text?
The same applies to [`mask-border-source`](https://drafts.fxtf.org/css-masking-1/#the-mask-border-source) where it's clarified that an empty or failing image will not mask the element, but a similar definition for `none` is missing.

Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/563 using your GitHub account


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Received on Monday, 17 June 2024 19:33:46 UTC