files/en-us/web/css/reference/properties/transform-box/index.md
The transform-box CSS property defines the layout box to which the {{cssxref("transform")}}, individual transform properties {{cssxref("translate")}}, {{cssxref("scale")}}, and {{cssxref("rotate")}}, and {{cssxref("transform-origin")}} properties relate.
/* Keyword values */
transform-box: content-box;
transform-box: border-box;
transform-box: fill-box;
transform-box: stroke-box;
transform-box: view-box;
/* Global values */
transform-box: inherit;
transform-box: initial;
transform-box: revert;
transform-box: revert-layer;
transform-box: unset;
The transform-box property is specified as one of the keyword values listed below.
content-box
border-box
fill-box
content-box.stroke-box
border-box.view-box
viewBox attribute, and the dimension of the reference box is set to the width and height values of the viewBox attribute. For elements with associated CSS layout box, acts as border-box.{{CSSInfo}}
{{csssyntax}}
In this example we have an SVG:
<svg id="svg" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 50 50">
<g>
<circle id="center" fill="red" r="1" transform="translate(25 25)" />
<circle id="boxcenter" fill="blue" r=".5" transform="translate(15 15)" />
<rect
id="box"
x="10"
y="10"
width="10"
height="10"
rx="1"
ry="1"
stroke="black"
fill="none" />
</g>
</svg>
In the CSS we have an animation that uses a transform to rotate the rectangle infinitely. transform-box: fill-box is used to make the transform-origin the center of the bounding box, so the rectangle spins in place. Without it, the transform origin is the center of the SVG canvas, and so you get a very different effect.
svg {
width: 80vh;
border: 1px solid #d9d9d9;
position: absolute;
margin: auto;
inset: 0;
}
#box {
transform-origin: 50% 50%; /* anything other than `0 0` to see the effect */
transform-box: fill-box;
animation: rotate-box 3s linear infinite;
}
@keyframes rotate-box {
to {
transform: rotate(360deg);
}
}
{{EmbedLiveSample("SVG transform-origin scoping", "", 400)}}
{{Specifications}}
{{Compat}}