SVGMaskElement: maskUnits property
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The read-only maskUnits property of the SVGMaskElement interface reflects the maskUnits attribute of a <mask> element which defines the coordinate system to use for the mask of the element.
Value
An SVGAnimatedEnumeration representing the coordinate system. The possible values are defined in the SVGUnitTypes interface:
0(SVG_UNIT_TYPE_UNKNOWN)-
The type is not one of the predefined types.
1(SVG_UNIT_TYPE_USERSPACEONUSE)-
Corresponds to a value of
userSpaceOnUsefor themaskUnitsattribute and means that all coordinates inside the element refer to the user coordinate system as defined when the mask was created. It is the default value. 2(SVG_UNIT_TYPE_OBJECTBOUNDINGBOX)-
Corresponds to a value of
objectBoundingBoxfor the attribute and means that all coordinates inside the element are relative to the bounding box of the element the mask is applied to. It means that the origin of the coordinate system is the top left corner of the object bounding box and the width and height of the object bounding box are considered to have a length of 1 unit value.
Examples
<div>
<svg
viewBox="0 0 100 100"
height="200"
width="200"
xmlns="http://www.w3.org/2000/svg">
<mask
id="mask1"
maskUnits="userSpaceOnUse"
x="20%"
y="20%"
width="60%"
height="60%">
<rect fill="black" x="0" y="0" width="100%" height="100%" />
<circle fill="white" cx="50" cy="50" r="35" />
</mask>
<mask
id="mask2"
maskUnits="objectBoundingBox"
x="20%"
y="20%"
width="60%"
height="60%">
<rect fill="black" x="0" y="0" width="100%" height="100%" />
<circle fill="white" cx="50" cy="50" r="35" />
<animate
attributeName="maskUnits"
values="objectBoundingBox;userSpaceOnUse"
dur="1s"
repeatCount="indefinite" />
</mask>
<!-- Some reference rect to materialized the mask -->
<rect id="r1" x="0" y="0" width="45" height="45" />
<rect id="r2" x="0" y="55" width="45" height="45" />
<rect id="r3" x="55" y="55" width="45" height="45" />
<rect id="r4" x="55" y="0" width="45" height="45" />
<!-- The first 3 rect are masked with useSpaceOnUse units -->
<use mask="url(#mask1)" href="#r1" fill="blue" />
<use mask="url(#mask1)" href="#r2" fill="green" />
<use mask="url(#mask1)" href="#r3" fill="yellow" />
<!-- The last rect is masked with objectBoundingBox units -->
<use mask="url(#mask2)" href="#r4" fill="lightblue" />
</svg>
</div>
<pre id="log"></pre>
const unitType = ["unknown", "userSpaceOnUse", "objectBoundingBox"];
const mask = document.getElementById("mask2");
const log = document.getElementById("log");
function displayLog() {
const baseValue = unitType[mask.maskUnits.baseVal];
const animValue = unitType[mask.maskUnits.animVal];
log.textContent = `The top-right 'maskUnits.baseVal' coord system : ${baseValue}\n`;
log.textContent += `The top-right 'maskUnits.animVal' coord system : ${animValue}`;
requestAnimationFrame(displayLog);
}
displayLog();
Specifications
| Specification |
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| CSS Masking Module Level 1 # dom-svgmaskelement-maskunits |
Browser compatibility
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maskUnits
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