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.

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

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

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

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 value luminance
Applies to <mask> elements
Inherited no
Computed value as specified
Animation type discrete

Formal syntax

luminance | alpha

Examples

Setting an alpha mask

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

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

Result

Setting a luminance mask

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

.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 (CSS Masking 1)
# the-mask-type

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
mask-type
24
79
35
No
15
7
37
25
35
14
7
1.5

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/mask-type