getBBox() - Web APIs 编辑

The SVGGraphicsElement.getBBox() allows us to determine the coordinates of the smallest rectangle in which the object fits. The coordinates returned are with respect to the current SVG space (after the application of all geometry attributes on all the elements contained in the target element).

Note: getBBox() must return the actual bounding box at the time the method was called—even in case the element has not yet been rendered. It also does not account for any transformation applied to the element or its parents.

getBBox returns different values than getBoundingClientRect(), as the latter returns value relative to the viewport

Syntax

let bboxRect = object.getBBox();

Return value

The returned value is a SVGRect object, which defines the bounding box. This value is irrespective of any transformation attribute applied to it or the parent elements.

Example

HTML

<svg viewBox="0 0 200 200" xmlns="http://www.w3.org/2000/svg">
    <g id="group_text_1">
        <text x="5" y="16" transform="scale(2, 2)">Hello World!</text>
        <text x="8" y="32" transform="translate(0 20) scale(1.25 1)">Hello World Again!</text>
    </g>
    <!-- Shows BBox in green -->
    <rect id="rect_1" stroke="#00ff00" stroke-width="3" fill="none"> </rect>
    <!-- Shows BoundingClientRect in red -->
    <rect id="rect_2" stroke="#ff0000" stroke-width="3" fill="none"></rect>
</svg>

JavaScript

var rectBBox = document.querySelector('#rect_1');
var rectBoundingClientRect = document.querySelector('#rect_2');
var groupElement = document.querySelector('#group_text_1');

var bboxGroup = groupElement.getBBox();
rectBBox.setAttribute('x', bboxGroup.x);
rectBBox.setAttribute('y', bboxGroup.y);
rectBBox.setAttribute('width', bboxGroup.width);
rectBBox.setAttribute('height', bboxGroup.height);

var boundingClientRectGroup = groupElement.getBoundingClientRect();
rectBoundingClientRect.setAttribute('x', boundingClientRectGroup.x);
rectBoundingClientRect.setAttribute('y', boundingClientRectGroup.y);
rectBoundingClientRect.setAttribute('width', boundingClientRectGroup.width);
rectBoundingClientRect.setAttribute('height', boundingClientRectGroup.height);

Specifications

See also

• getBBox in SVG Primer