Touch: altitudeAngle property

Limited availability

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

The altitudeAngle read-only property of the Touch interface returns the angle between a transducer (a pointer or stylus) axis and the X-Y plane of a device screen. The altitude angle describes whether the transducer is perpendicular to the screen, parallel, or at some angle in between.

Note: The default value of altitudeAngle is 0 (parallel to the device surface), which differs from the PointerEvent.altitudeAngle property, which defaults to π/2 (perpendicular to the surface).

For hardware and platforms that do not report tilt or angle, the value is 0.

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,
);