The mask-border-slice
CSS property divides the image set by mask-border-source
into regions. These regions are used to form the components of an element's mask border.
The mask-border-slice
CSS property divides the image set by mask-border-source
into regions. These regions are used to form the components of an element's mask border.
/* All sides */ mask-border-slice: 30%; /* top and bottom | left and right */ mask-border-slice: 10% 30%; /* top | left and right | bottom */ mask-border-slice: 30 30% 45; /* top | right | bottom | left */ mask-border-slice: 7 12 14 5; /* Using the `fill` keyword */ mask-border-slice: 10% fill 7 12; /* Global values */ mask-border-slice: inherit; mask-border-slice: initial; mask-border-slice: revert; mask-border-slice: revert-layer; mask-border-slice: unset;
The mask-border-slice
property may be specified using one to four <number-percentage>
values to represent the position of each image slice. Negative values are invalid; values greater than their corresponding dimension are clamped to 100%
.
The optional fill
value, if used, can be placed anywhere in the declaration.
<number>
Represents an edge offset in pixels for raster images and coordinates for vector images. For vector images, the number is relative to the element's size, not the size of the source image, so percentages are generally preferable in these cases.
<percentage>
Represents an edge offset as a percentage of the source image's size: the width of the image for horizontal offsets, the height for vertical offsets.
fill
Preserves the middle image region. Its width and height are sized to match the top and left image regions, respectively.
The slicing process creates nine regions in total: four corners, four edges, and a middle region. Four slice lines, set a given distance from their respective sides, control the size of the regions.
The above diagram illustrates the location of each region.
fill
is set.The mask-border-repeat
, mask-border-width
, and mask-border-outset
properties determine how these regions are used to form the final mask border.
Initial value | 0 |
---|---|
Applies to | all elements; In SVG, it applies to container elements excluding the <defs> element and all graphics elements |
Inherited | no |
Percentages | refer to size of the mask border image |
Computed value | as specified |
Animation type | discrete |
This property doesn't appear to be supported anywhere yet. When it eventually starts to be supported, it will serve to define the size of the slices taken from the source image, and used to create the border mask.
mask-border-slice: 30 fill;
Chromium-based browsers support an outdated version of this property — mask-box-image-slice
— with a prefix:
-webkit-mask-box-image-slice: 30 fill;
Note: The mask-border
page features a working example (using the out-of-date prefixed border mask properties supported in Chromium), so you can get an idea of the effect.
Note: The fill keyword needs to be included if you want the element's content to be visible.
Specification |
---|
CSS Masking Module Level 1 # the-mask-border-slice |
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
mask-border-slice |
1 | 79 | NoSee bug 877294. |
No | 15 | 3.1 | 4.4 | 18 | NoSee bug 877294. |
14 | 3 | 1.0 |
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https://developer.mozilla.org/en-US/docs/Web/CSS/mask-border-slice