CameraControl.meteringAreas

« DOM Reference

Non-standard
This feature is not on a current W3C standards track, but it is supported on the Firefox OS platform. Although implementations may change in the future and it is not supported widely across browsers, it is suitable for use in code dedicated to Firefox OS apps.

This API is available on Firefox OS for certified applications only.

Summary

The meteringAreas property is an Array of one or more Area objects that define where the camera will perform light metering.

If the array contains more objects than the number defined inside CameraCapabilities.maxMeteringAreas, extra objects will be ignored.

If set to null, the camera will determine the light metering areas by itself.

Area

Area objects are arbitrary JavaScript objects which describe an area of the sensor field. They are used in the Array presented by the meteringAreas property. Each object must have the following properties:

top
A number ranging from -1000 at the topmost of the sensor to 1000 at the bottommost of the sensor.
left
A number ranging from -1000 at the leftmost of the sensor to 1000 at the rightmost of the sensor.
bottom
A number ranging from -1000 at the topmost of the sensor to 1000 at the bottommost of the sensor.
right
A number ranging from -1000 at the leftmost of the sensor to 1000 at the rightmost of the sensor.
weight
A number defining the relative importance of the area against other areas, range from 0 to 1000.

Note: Objects missing one or more of these properties will be ignored.

Syntax

var areas = instanceOfCameraControl.meteringAreas

Value

Return an Array of one or more objects that define where the camera will perform light metering.

Example

var options = {
  camera: navigator.mozCameras.getListOfCameras()[0]
};
 
function onSuccess( camera ) {
  var max = camera.capabilities.maxMeteringAreas;

  if (max > 0) {
    camera.meteringAreas = [
      {top: -500, bottom: 500, left: -500, right: 500, weight: 1000}
    ];
  }
};

navigator.mozCameras.getCamera(options, onSuccess)

Specification

Not part of any specification; however, this API should be removed when the WebRTC Capture and Stream API has been implemented.

See also

Document Tags and Contributors

Contributors to this page: Sheppy, kscarfone, ajaybhat, Jeremie
Last updated by: ajaybhat,