DOMPoint

A DOMPoint object represents a 2D or 3D point in a coordinate system; it includes values for the coordinates in up to three dimensions, as well as an optional perspective value. DOMPoint is based on DOMPointReadOnly but allows its properties' values to be changed.

In general, a positive x component represents a position to the right of the origin, a positive y component is downward from the origin, and a positive z component extends outward from the screen (in other words, toward the user).

Constructor

DOMPoint()

Creates and returns a new DOMPoint object given the values of zero or more of its coordinate components and optionally the w perspective value. You can also use an existing DOMPoint or DOMPointReadOnly or a DOMPointInit dictionary to create a new point by calling the DOMPoint.fromPoint() static method.

Methods

DOMPoint inherits methods from its parent, DOMPointReadOnly.

fromPoint()

Creates a new mutable DOMPoint object given an existing point or a DOMPointInit dictionary which provides the values for its properties.

Properties

DOMPoint inherits properties from its parent, DOMPointReadOnly.

DOMPoint.x

The x coordinate of the DOMPoint.

DOMPoint.y

The y coordinate of the DOMPoint.

DOMPoint.z

The z coordinate of the DOMPoint.

DOMPoint.w

The perspective value of the DOMPoint.

Examples

In the WebVR API, DOMPoint values are used to represent points in the coordinate space that the user's head mounted display exists in. In the following snippet, the position of the VR HMD can be retrieved by first grabbing a reference to the position sensor's current state using PositionSensorVRDevice.getState(), then accessing the resulting VRPositionState's position property, which returns a DOMPoint. Note below the usage of position.x, position.y, and position.z.

function setView() {
  var posState = gPositionSensor.getState();

  if (posState.hasPosition) {
    posPara.textContent = 'Position: x' + roundToTwo(posState.position.x) + " y"
                                        + roundToTwo(posState.position.y) + " z"
                                        + roundToTwo(posState.position.z);
    xPos = -posState.position.x * WIDTH * 2;
    yPos = posState.position.y * HEIGHT * 2;

    if (-posState.position.z > 0.01) {
      zPos = -posState.position.z;
    } else {
      zPos = 0.01;
    }
  }

  /* ... */

}

Specifications

Browser compatibility

See also

• DOMRect
• DOMMatrix