Touch: altitudeAngle property

{{ APIRef("Touch Events") }}

The altitudeAngle read-only property of the {{domxref("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 {{domxref("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.

Value

An angle in radians between 0 and π/2, where 0 is parallel to the device surface (X-Y plane), and π/2 is perpendicular to the surface.

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,
);

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("Touch.azimuthAngle")}}
• {{domxref("Touch.touchType")}}
• {{domxref("PointerEvent.altitudeAngle")}}
• Touch events