mask-mode

Baseline 2023

Newly available

Since December 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

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

Syntax

css

/* 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: revert;
mask-mode: revert-layer;
mask-mode: unset;

The mask-mode property is specified as one or more of the keyword values listed below, separated by commas.

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 definition

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
Computed value	as specified
Animation type	discrete

Formal syntax

mask-mode = 
  <masking-mode>#  

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

Examples

Using alpha mask mode

html

<div class="masked"></div>

css

.masked {
  width: 227px;
  height: 200px;
  background: blue linear-gradient(red, blue);

  mask-image: url(https://mdn.github.io/shared-assets/images/examples/mdn.svg);
  mask-mode: alpha;
}

Specifications

Specification
CSS Masking Module Level 1 # the-mask-mode