The mask
CSS property alters the visibility of an element by either partially or fully hiding it. This is accomplished by either masking or clipping the image at specific points.
/* Keyword values */ mask: none; /* Image values */ mask: url(mask.png); /* Pixel image used as mask */ mask: url(masks.svg#star); /* Element within SVG graphic used as mask */ /* Combined values */ mask: url(masks.svg#star) luminance; /* Element within SVG graphic used as luminance mask */ mask: url(masks.svg#star) 40px 20px; /* Element within SVG graphic used as mask positioned 40px from the top and 20px from the left */ mask: url(masks.svg#star) 0 0/50px 50px; /* Element within SVG graphic used as mask with a width and height of 50px */ mask: url(masks.svg#star) repeat-x; /* Element within SVG graphic used as horizontally repeated mask */ mask: url(masks.svg#star) stroke-box; /* Element within SVG graphic used as mask extending to the box enclosed by the stroke */ mask: url(masks.svg#star) exclude; /* Element within SVG graphic used as mask and combined with background using non-overlapping parts */ /* Global values */ mask: inherit; mask: initial; mask: unset;
The mask
shorthand also resets mask-border
to its initial value. It is therefore recommended to use the mask
shorthand rather than other shorthands or the individual properties to override any mask settings earlier in the cascade. This will ensure that mask-border
has also been reset to allow the new styles to take effect.
Initial value | as each of the properties of the shorthand:
|
---|---|
Applies to | all elements; In SVG, it applies to container elements excluding the <defs> element and all graphics elements |
Inherited | no |
Percentages | as each of the properties of the shorthand:
|
Media | visual |
Computed value | as each of the properties of the shorthand:
|
Animation type | as each of the properties of the shorthand:
|
Canonical order | per grammar |
Creates stacking context | yes |
Syntax
Values
<mask-reference>
- Sets the mask image source. See
mask-image
. <masking-mode>
- Sets the masking mode of the mask image. See
mask-mode
. <position>
- Sets the position of the mask image. See
mask-position
. <bg-size>
- Sets the size of the mask image. See
mask-size
. <repeat-style>
- Sets the repetition of the mask image. See
mask-repeat
. <geometry-box>
- If only one <geometry-box> value is given, it sets both
mask-origin
andmask-clip
. If two <geometry-box> values are present, then the first setsmask-origin
and the second setsmask-clip
. <geometry-box> | no-clip
- Sets the area that is affected by the mask image. See
mask-clip
. <compositing-operator>
- Sets the compositing operation used on the current mask layer. See
mask-composite
.
Formal syntax
<mask-layer>#where
<mask-layer> = <mask-reference> || <position> [ / <bg-size> ]? || <repeat-style> || <geometry-box> || [ <geometry-box> | no-clip ] || <compositing-operator> || <masking-mode>
where
<mask-reference> = none | <image> | <mask-source>
<position> = [[ left | center | right | top | bottom | <length-percentage> ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] | [ center | [ left | right ] <length-percentage>? ] && [ center | [ top | bottom ] <length-percentage>? ]]
<bg-size> = [ <length-percentage> | auto ]{1,2} | cover | contain
<repeat-style> = repeat-x | repeat-y | [ repeat | space | round | no-repeat ]{1,2}
<geometry-box> = <shape-box> | fill-box | stroke-box | view-box
<compositing-operator> = add | subtract | intersect | exclude
<masking-mode> = alpha | luminance | match-sourcewhere
<image> = <url> | <image()> | <image-set()> | <element()> | <cross-fade()> | <gradient>
<mask-source> = <url>
<length-percentage> = <length> | <percentage>
<shape-box> = <box> | margin-boxwhere
<image()> = image( [ [ <image> | <string> ]? , <color>? ]! )
<image-set()> = image-set( <image-set-option># )
<element()> = element( <id-selector> )
<cross-fade()> = cross-fade( <cf-mixing-image> , <cf-final-image>? )
<gradient> = <linear-gradient()> | <repeating-linear-gradient()> | <radial-gradient()> | <repeating-radial-gradient()>
<box> = border-box | padding-box | content-boxwhere
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
<image-set-option> = [ <image> | <string> ] <resolution>
<cf-mixing-image> = <percentage>? && <image>
<cf-final-image> = <image> | <color>
<linear-gradient()> = linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )
<repeating-linear-gradient()> = repeating-linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )
<radial-gradient()> = radial-gradient( [ <ending-shape> || <size> ]? [ at <position> ]? , <color-stop-list> )
<repeating-radial-gradient()> = repeating-radial-gradient( [ <ending-shape> || <size> ]? [ at <position> ]? , <color-stop-list> )where
<rgb()> = rgb( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<rgba()> = rgba( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<hsl()> = hsl( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
<hsla()> = hsla( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
<side-or-corner> = [ left | right ] || [ top | bottom ]
<color-stop-list> = <color-stop>#{2,}
<ending-shape> = circle | ellipse
<size> = closest-side | farthest-side | closest-corner | farthest-corner | <length> | <length-percentage>{2}where
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>
<color-stop> = <color> <length-percentage>?
Examples
.target { mask: url(#c1) luminance; } .anothertarget { mask: url(resources.svg#c1) 50px 30px/10px 10px repeat-x exclude; }
Specifications
Specification | Status | Comment |
---|---|---|
CSS Masking Module Level 1 The definition of 'mask' in that specification. |
Candidate Recommendation | Extends its usage to HTML elements. Extends its syntax by making it a shorthand for the new mask-* properties defined in that specification. |
Scalable Vector Graphics (SVG) 1.1 (Second Edition) The definition of 'mask' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 11 | Yes | Yes3 | No | Yes1 | 41 |
Applies to HTML elements | Yes -webkit- | ? | 3.5 | No | Yes -webkit- | No |
Shorthand for mask-* properties | Yes -webkit- | ? | 53 | No | Yes -webkit- | No |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | 2.1 Yes -webkit- | ? | Yes | Yes | ? | ? | 3.2 -webkit- |
Applies to HTML elements | ? | ? | ? | ? | ? | ? | ? |
Shorthand for mask-* properties | ? | ? | ? | 53 | ? | ? | ? |
1. While the property is recognized, values applied to it don't have any effect.
2. The prefixed property can be used with SVG and HTML with a slightly different syntax, which allows setting the non-standard -webkit-mask-attachment
property.
3. From Firefox 10, the default color space when handling masks is sRGB. Previously, the default and only supported color space was linear RGB. This changes the appearance of mask effects, but brings Firefox into compliance with the second edition of the SVG 1.1 specification.