mask-mode

The mask-mode CSS property indicates whether the mask reference defined by mask-image is treated as a luminance or alpha mask.

Initial value	match-source
Applies to	all elements; In SVG, it applies to container elements excluding the <defs> element and all graphics elements
Inherited	no
Media	visual
Computed value	as specified
Animation type	discrete
Canonical order	the unique non-ambiguous order defined by the formal grammar

Syntax

/* Keyword values */
mask-mode: alpha;
mask-mode: luminance;
mask-mode: match-source;

/* Multiple values */
mask-mode: alpha, match-source;

/* Global values */
mask-mode: inherit;
mask-mode: initial;
mask-mode: unset;

Values

alpha

This keyword indicates that the transparency (alpha channel) values of the mask layer image should be used as the mask values.

luminance

This keyword indicates that the luminance values of the mask layer image should be used as the mask values.

match-source

If the mask-image property is of type <mask-source>, the luminance values of the mask layer image should be used as the mask values.

If it is of type <image>, the alpha values of the mask layer image should be used as the mask values.

Formal syntax

<masking-mode>#
where 
<masking-mode> = alpha | luminance | match-source

Example

CSS Content

#masked {
  width: 227px;
  height: 200px;
  background: blue linear-gradient(red, blue);
  mask-image: url(https://mdn.mozillademos.org/files/12668/MDN.svg);
  mask-mode: alpha; /* Can be changed in the live sample */
}

Specifications

Specification	Status	Comment
CSS Masking Level 1 The definition of 'mask-mode' in that specification.	Candidate Recommendation	Initial definition

Browser compatibility

[1] This feature is not implemented yet. It is only available in Nightly and Dev Edition. See bug 1251161.