CameraControl

When you use the CameraManager.getCamera() method to get a reference to a camera, you specify a callback function to be invoked on success. That function receives as a parameter a CameraControl object. You can use its methods and properties to manage and make use of the camera.

Properties

CameraControl.capabilities 只读

A CameraCapabilities object indicating all the capabilities for the given camera.

CameraControl.effect

A string defining the effect to be used by the camera (none by default). Its value must be one of the values available in CameraCapabilities.effects.

CameraControl.exposureCompensation 只读

A value used to compensate the camera exposure. This attribute is read-only; to change the exposure, you need to call the CameraControl.setExposureCompensation() method.

CameraControl.flashMode

A string that defines how the flash, if any, is to be used; this is auto by default if the device has a flash, none otherwise. When set, its value must be chosen from the list of options specified by  CameraCapabilities.flashModes.

CameraControl.focalLength 只读

A number that express the camera's focal length in millimeters.

CameraControl.focusAreas

An Array of one or more objects that define where the camera will perform auto-focusing.

CameraControl.focusDistanceFar 只读

This value is a distance in meter used with CameraControl.focusDistanceNear to defined the image's depth of field. The value for this property may be Infinity.

CameraControl.focusDistanceNear 只读

This value is a distance in meter used with CameraControl.focusDistanceFar to defined the image's depth of field.

CameraControl.focusDistanceOptimum 只读

This value is a distance in meter where the subject will appear sharpest.

CameraControl.focusMode

A string that defines which kind of focus mode the camera should use (auto or fixed by default). Its value must be chosen from CameraCapabilities.focusModes.

CameraControl.meteringAreas

An Array of one or more objects that define where the camera will perform auto-focusing.

CameraControl.onShutter

A handler for the camera's "shutter" event, to trigger a shutter sound and/or a visual shutter indicator.

CameraControl.onClosed

A handler called when a new CameraControl object in the same app takes over the camera.

CameraControl.onRecorderStateChange

A function to call when the recorder changes state, either because the recording process encountered an error, or because one of the recording limits (see CameraControl.startRecording()) was reached.

CameraControl.sceneMode

A string that defines which scene mode the camera is to use (auto by default). Its value must be chosen from CameraCapabilities.sceneModes.

CameraControl.whiteBalanceMode

A string that defines which white balance mode the camera is to use (auto by default). Its value must be chosen from CameraCapabilities.whiteBalanceModes.

CameraControl.zoom

A number that defines which kind of zoom factor mode the camera is to use (1 by default). Its value must be chosen from CameraCapabilities.zoomRatios.

Methods

CameraControl.autoFocus()

Tells the camera to attempt to focus the image.

CameraControl.getPreviewStream()

Gets a video stream from the camera; you can use this in an arbitrary context.

CameraControl.getPreviewStreamVideoMode()

Gets a video stream from the camera based on a specific video mode.

CameraControl.release()

Releases the camera so that other applications can use it.

CameraControl.resumePreview()

Resumes the preview video stream after it's been paused by a call to CameraControl.takePicture().

CameraControl.setExposureCompensation()

Lets you specify the exposure compensation factor.

CameraControl.startRecording()

Lets you start recording a video stream.

CameraControl.stopRecording()

Lets you stop recording a video stream.

CameraControl.takePicture()

Lets you capture a single image, receiving it as a Blob.

Specification

Not part of any specification as yet; this will probably be replaced by WebRTC when it gains more widespread support on mobile devices.

Permissions

Up until Firefox OS 1.4, The Camera API was a certified API, so not accessible to third party apps. From Firefox OS 2.0 onwards, the permission level has been downgraded to privileged, so it is now available for developers to use in their apps.

"permissions": {
  "camera": {
    "description": "Required for accessing cameras on the device."
  }
}

See also

• CameraManager
• CameraCapabilities
• navigator.mozCamera