mask-type

The mask-type CSS property sets whether an SVG <mask> element is used as a luminance or an alpha mask. It applies to the <mask> element itself.

This property may be overridden by the mask-mode property, which has the same effect but applies to the element where the mask is used. Alpha masks will generally be faster to render.

Syntax

css
/* Keyword values */
mask-type: luminance;
mask-type: alpha;

/* Global values */
mask-type: inherit;
mask-type: initial;
mask-type: revert;
mask-type: revert-layer;
mask-type: unset;

The mask-type property is specified as one of the keyword values listed below.

Values

luminance

Is a keyword indicating that the associated mask image is a luminance mask, i.e., that its relative luminance values must be used when applying it.

alpha

Is a keyword indicating that the associated mask image is an alpha mask, i.e., that its alpha channel values must be used when applying it.

Formal definition

Initial valueluminance
Applies to<mask> elements
Inheritedno
Computed valueas specified
Animation typediscrete

Formal syntax

mask-type = 
  luminance  |
  alpha

Examples

Setting an alpha mask

HTML

html
<div class="redsquare"></div>
<svg
  version="1.1"
  xmlns="http://www.w3.org/2000/svg"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  width="0"
  height="0">
  <defs>
    <mask id="m" maskContentUnits="objectBoundingBox" style="mask-type:alpha">
      <rect
        x=".1"
        y=".1"
        width=".8"
        height=".8"
        fill="red"
        fill-opacity="0.7" />
    </mask>
  </defs>
</svg>

CSS

css
.redsquare {
  height: 100px;
  width: 100px;
  background-color: rgb(128 128 128);
  border: solid 1px black;
  mask: url("#m");
}

Result

Setting a luminance mask

HTML

html
<div class="redsquare"></div>
<svg
  version="1.1"
  xmlns="http://www.w3.org/2000/svg"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  width="0"
  height="0">
  <defs>
    <mask
      id="m"
      maskContentUnits="objectBoundingBox"
      style="mask-type:luminance">
      <rect
        x=".1"
        y=".1"
        width=".8"
        height=".8"
        fill="red"
        fill-opacity="0.7" />
    </mask>
  </defs>
</svg>

CSS

css
.redsquare {
  height: 100px;
  width: 100px;
  background-color: rgb(128 128 128);
  border: solid 1px black;
  mask: url("#m");
}

Result

Specifications

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

Browser compatibility

BCD tables only load in the browser

See also