The mask-origin CSS property sets the origin of a mask.

/* Keyword values */ mask-origin: content-box; mask-origin: padding-box; mask-origin: border-box; mask-origin: margin-box; mask-origin: fill-box; mask-origin: stroke-box; mask-origin: view-box;  /* Multiple values */ mask-origin: padding-box, content-box; mask-origin: view-box, fill-box, border-box;  /* Non-standard keyword values */ -webkit-mask-origin: content; -webkit-mask-origin: padding; -webkit-mask-origin: border;  /* Global values */ mask-origin: inherit; mask-origin: initial; mask-origin: revert; mask-origin: unset; 

mask-origin

The mask-origin CSS property sets the origin of a mask.

/* Keyword values */ mask-origin: content-box; mask-origin: padding-box; mask-origin: border-box; mask-origin: margin-box; mask-origin: fill-box; mask-origin: stroke-box; mask-origin: view-box;  /* Multiple values */ mask-origin: padding-box, content-box; mask-origin: view-box, fill-box, border-box;  /* Non-standard keyword values */ -webkit-mask-origin: content; -webkit-mask-origin: padding; -webkit-mask-origin: border;  /* Global values */ mask-origin: inherit; mask-origin: initial; mask-origin: revert; mask-origin: unset; 

For elements rendered as a single box, this property specifies the mask positioning area. In other words, this property specifies the origin position of an image specified by the mask-image CSS property. For elements rendered as multiple boxes, such as inline boxes on several lines or boxes on several pages, it specifies which boxes box-decoration-break operates upon to determine the mask positioning area.

Syntax

One or more of the keyword values listed below, separated by commas.

Values

content-box

The position is relative to the content box.

padding-box

The position is relative to the padding box. For single boxes 0 0 is the upper left corner of the padding edge, 100% 100% is the lower right corner.

border-box

The position is relative to the border box.

margin-box

The position is relative to the margin box.

fill-box

The position is relative to the object bounding box.

stroke-box

The position is relative to the stroke bounding box.

view-box

Uses the nearest SVG viewport as reference box. If a viewBox attribute is specified for the element creating the SVG viewport, the reference box is positioned at the origin of the coordinate system established by the viewBox attribute and the dimension of the reference box is set to the width and height values of the viewBox attribute.

content

Same as content-box.

padding

Same as padding-box.

border

Same as border-box.

Formal definition

Initial value	border-box
Applies to	all elements; In SVG, it applies to container elements excluding the defs element and all graphics elements
Inherited	no
Computed value	as specified
Animation type	discrete

Formal syntax

<geometry-box>#
where <geometry-box> = <shape-box> | fill-box | stroke-box | view-box
where <shape-box> = <box> | margin-box
where <box> = border-box | padding-box | content-box

Examples

Setting mask origin to border-box

Try some of the other possible values by updating the CSS in the box below.

Specifications

Specification
CSS Masking Module Level 1 # the-mask-origin

See also

Clipping and Masking in CSS

Last modified: Aug 12, 2021, by MDN contributors

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