SVGLengthList

The SVGLengthList interface defines a list of SVGLength objects. It is used for the baseVal and animVal properties of SVGAnimatedLengthList.

An SVGLengthList object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown.

An SVGLengthList object is indexable and can be accessed like an array.

Instance properties

length

The number of items in the list.

numberOfItems

The number of items in the list.

Instance methods

appendItem()

Inserts a new item at the end of the list.

clear()

Clears all existing items from the list, with the result being an empty list.

initialize()

Clears all existing items from the list and re-initializes the list to hold the single item specified by the parameter.

getItem()

Returns the specified item from the list.

insertItemBefore()

Inserts a new item into the list at the specified position.

removeItem()

Removes an existing item from the list.

replaceItem()

Replaces an existing item in the list with a new item.

Examples

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Using SVGLengthList

An SVGLengthList object can be retrieved from an SVGAnimatedLengthList object, which itself is retrievable from many animatable length attributes, such as SVGTextPositioningElement.x.

HTML

html
<svg
  viewBox="0 0 200 100"
  xmlns="http://www.w3.org/2000/svg"
  width="200"
  height="100">
  <text id="text1" x="10" y="50">Hello</text>
</svg>
<button id="equally-distribute">Equally distribute letters</button>
<button id="reset-spacing">Reset spacing</button>
<div>
  <b>Current <code>SVGLengthList</code></b>
  <pre><output id="output"></output></pre>
</div>

JavaScript

js
const text = document.getElementById("text1");
const output = document.getElementById("output");
const list = text.x.baseVal;
function equallyDistribute() {
  list.clear();
  for (let i = 0; i < text.textContent.length; i++) {
    const length = text.ownerSVGElement.createSVGLength();
    length.value = i * 20 + 10;
    list.appendItem(length);
  }
  printList();
}
function resetSpacing() {
  const length = text.ownerSVGElement.createSVGLength();
  length.value = 10;
  list.initialize(length);
  printList();
}
function printList() {
  output.textContent = "";
  for (let i = 0; i < list.length; i++) {
    output.innerText += `${list.getItem(i).value}\n`;
  }
}
printList();

document
  .getElementById("equally-distribute")
  .addEventListener("click", equallyDistribute);
document
  .getElementById("reset-spacing")
  .addEventListener("click", resetSpacing);

Result

Specifications

See also