SVGLengthList

{{APIRef("SVG")}}

The SVGLengthList interface defines a list of {{ domxref("SVGLength") }} objects. It is used for the {{domxref("SVGAnimatedLengthList.baseVal", "baseVal")}} and {{domxref("SVGAnimatedLengthList.animVal", "animVal")}} properties of {{domxref("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

• {{domxref("SVGLengthList.length", "length")}}
  • : The number of items in the list.
• {{domxref("SVGLengthList.numberOfItems", "numberOfItems")}}
  • : The number of items in the list.

Instance methods

• {{domxref("SVGLengthList.appendItem", "appendItem()")}}
  • : Inserts a new item at the end of the list.
• {{domxref("SVGLengthList.clear", "clear()")}}
  • : Clears all existing items from the list, with the result being an empty list.
• {{domxref("SVGLengthList.initialize", "initialize()")}}
  • : Clears all existing items from the list and re-initializes the list to hold the single item specified by the parameter.
• {{domxref("SVGLengthList.getItem", "getItem()")}}
  • : Returns the specified item from the list.
• {{domxref("SVGLengthList.insertItemBefore", "insertItemBefore()")}}
  • : Inserts a new item into the list at the specified position.
• {{domxref("SVGLengthList.removeItem", "removeItem()")}}
  • : Removes an existing item from the list.
• {{domxref("SVGLengthList.replaceItem", "replaceItem()")}}
  • : Replaces an existing item in the list with a new item.

Examples

Using SVGLengthList

An SVGLengthList object can be retrieved from an {{domxref("SVGAnimatedLengthList")}} object, which itself is retrievable from many animatable length attributes, such as {{domxref("SVGTextPositioningElement.x")}}.

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

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

{{EmbedLiveSample("Using SVGLengthList", "", "300")}}

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("SVGNumberList")}}
• {{domxref("SVGPointList")}}
• {{domxref("SVGStringList")}}
• {{domxref("SVGTransformList")}}