maskContentUnits

The maskContentUnits attribute indicates which coordinate system to use for the contents of the <mask> element.

You can use this attribute with the following SVG elements:

Example

<svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <mask id="myMask1" maskContentUnits="userSpaceOnUse">
    <rect   fill="black" x="0" y="0" width="100%" height="100%" />
    <circle fill="white" cx="50" cy="50" r="35" />
  </mask>

  <mask id="myMask2" maskContentUnits="objectBoundingBox">
    <rect   fill="black" x="0" y="0" width="100%" height="100%" />
    <circle fill="white" cx=".5" cy=".5" r=".35" />
  </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(#myMask1)" xlink:href="#r1" fill="red" />
  <use mask="url(#myMask1)" xlink:href="#r2" fill="red" />
  <use mask="url(#myMask1)" xlink:href="#r3" fill="red" />

  <!-- The last rect is masked with objectBoundingBox units -->
  <use mask="url(#myMask2)" xlink:href="#r4" fill="red" />
</svg>

mask

For <mask>, maskContentUnits defines the coordinate system in use for the content of the element.

Value userSpaceOnUse | objectBoundingBox
Default value userSpaceOnUse
Animatable Yes
userSpaceOnUse

This value indicates that all coordinates inside the <mask> element refer to the user coordinate system as defined when the mask was created.

objectBoundingBox

This value indicates that all coordinates inside the <mask> element are relative to the bounding box of the element the mask is applied to. A bounding box could be considered the same as if the content of the <mask> were bound to a "0 0 1 1" viewbox.

Specifications

Specification Status Comment
CSS Masking Module Level 1
The definition of 'maskContentUnits' in that specification.		 Candidate Recommendation
Scalable Vector Graphics (SVG) 1.1 (Second Edition)
The definition of 'maskContentUnits' in that specification.		 Recommendation Initial definition

Browser compatibility

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