mask-position - CSS: Cascading Style Sheets 编辑

The mask-position CSS property sets the initial position, relative to the mask position layer set by mask-origin, for each defined mask image.

/* Keyword values */
mask-position: top;
mask-position: bottom;
mask-position: left;
mask-position: right;
mask-position: center;

/* <position> values */
mask-position: 25% 75%;
mask-position: 0px 0px;
mask-position: 10% 8em;

/* Multiple values */
mask-position: top right;
mask-position: 1rem 1rem, center;

/* Global values */
mask-position: inherit;
mask-position: initial;
mask-position: unset;

Syntax

One or more <position> values, separated by commas.

Values

<position>

One to four values representing a 2D position regarding the edges of the element's box. Relative or absolute offsets can be given. Note that the position can be set outside of the element's box.

Formal definition

Formal syntax

<position>#
where 
<position> = [ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]
where 
<length-percentage> = <length> | <percentage>

Examples

Setting mask position

CSS

#wrapper {
  border: 1px solid black;
  width: 250px;
  height: 250px;
}

#masked {
  width: 250px;
  height: 250px;
  background: blue linear-gradient(red, blue);
  mask-image: url(https://mdn.mozillademos.org/files/12676/star.svg);
  mask-repeat: no-repeat;
  mask-position: top right; /* Can be changed in the live sample */
  margin-bottom: 10px;
}

HTML

<div id="wrapper">
  <div id="masked">
  </div>
</div>
<select id="maskPosition">
  <option value="top">top</option>
  <option value="center">center</option>
  <option value="bottom">bottom</option>
  <option value="top right" selected>top right</option>
  <option value="center center">center center</option>
  <option value="bottom left">bottom left</option>
  <option value="10px 20px">10px 20px</option>
  <option value="60% 20%">60% 20%</option>
</select>

JavaScript

var maskPosition = document.getElementById("maskPosition");
maskPosition.addEventListener("change", function (evt) {
  document.getElementById("masked").style.maskPosition = evt.target.value;
});

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Clipping and Masking in CSS