The mask-composite CSS property represents a compositing operation used on the current mask layer with the mask layers below it.

/* Keyword values */ mask-composite: add; mask-composite: subtract; mask-composite: intersect; mask-composite: exclude;  /* Global values */ mask-composite: inherit; mask-composite: initial; mask-composite: revert; mask-composite: unset; 

mask-composite

The mask-composite CSS property represents a compositing operation used on the current mask layer with the mask layers below it.

/* Keyword values */ mask-composite: add; mask-composite: subtract; mask-composite: intersect; mask-composite: exclude;  /* Global values */ mask-composite: inherit; mask-composite: initial; mask-composite: revert; mask-composite: unset; 

Syntax

One or more of the keyword values listed below, separated by commas.

Values

For the composition the current mask layer is referred to as source, while all layers below it are referred to as destination.

add

The source is placed over the destination.

subtract

The source is placed, where it falls outside of the destination.

intersect

The parts of source that overlap the destination, replace the destination.

exclude

The non-overlapping regions of source and destination are combined.

Formal definition

Initial value	add
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

<compositing-operator>#
where <compositing-operator> = add | subtract | intersect | exclude

Examples

Compositing mask layers with addition

Specifications

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

See also

Clipping and Masking in CSS

Last modified: Aug 12, 2021, by MDN contributors