CSS transform-box

The CSS transform-box property defines the reference box to which the transform and transform-origin properties relate.

All transformations defined by the transform and transform-origin properties are relative to the position and dimensions of the reference box of the element.

Syntax

The syntax goes like this:

Which means that the reference box is specified by one of the following:

Explanation of the possible values:

content-box: Uses the content box as reference box. The reference box of a table is the border box of its table wrapper box, not its table box.
border-box: Uses the border box as reference box. The reference box of a table is the border box of its table wrapper box, not its table box.
fill-box: Uses the object bounding box as reference box. The object bounding box is the bounding box that contains only an element's geometric shape. For basic shapes, this is the area that is filled.
stroke-box: Uses the stroke bounding box as reference box. The stroke bounding box is the bounding box that contains an element's geometric shape and its stroke shape.
view-box: Uses the nearest SVG viewport as reference box.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

initial: Represents the value specified as the property's initial value.
inherit: Represents the computed value of the property on the element's parent.
unset: This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

Basic Property Information

Initial Value

view-box

Applies To

This property applies only to transformable elements.

In HTML, a transformable element is either:

a block-level or atomic inline-level element
or whose CSS display property computes to table-row, table-row-group, table-header-group, table-footer-group, table-cell, or table-caption

In SVG, a transformable element is an element which has the attributes transform, patternTransform or gradientTransform.

Inherited?

Computed Value

Specified keyword.

Animatable

Discrete

CSS Specifications

The transform-box property is defined in CSS Transforms Module Level 1 (W3C Candidate Recommendation, 14 February 2019).

Browser Support

The following table provided by Caniuse.com shows the level of browser support for this feature.

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.