Touch: azimuthAngle property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

The azimuthAngle read-only property of the Touch interface returns the angle between the Y-Z plane and the plane containing both the transducer (pointer or stylus) axis and the Y axis. This represents the compass direction that the transducer is pointing in relative to the device surface.

For hardware and platforms that do not report tilt or angle, the value is 0. When the transducer is perpendicular to the surface (altitudeAngle of π/2), the value is 0.

Value

An angle in radians between 0 and 2π, where 0 represents a transducer whose cap is pointing in the direction of increasing X values (point to "3 o'clock" if looking straight down) on the X-Y plane, and the values progressively increase when going clockwise (π/2 at "6 o'clock", π at "9 o'clock", 3π/2 at "12 o'clock").

Example

Basic usage

someElement.addEventListener(
  "touchstart",
  (event) => {
    for (const touch of event.changedTouches) {
      // Log the altitude and azimuth angles for each stylus touch point.
      if (touch.touchType === "stylus") {
        console.log(`altitudeAngle: ${touch.altitudeAngle}`);
        console.log(`azimuthAngle: ${touch.azimuthAngle}`);
      }
    }
  },
  false,
);