Class “Camera”

Object > NativeObject > Camera

A Camera provides access to the device’s camera. The Camera can be used as a source for a CameraView to display a live preview feed or to capture a photo.

In order to capture an image or to show a camera preview image the app has to have the 'camera' permission.

Type: Camera extends NativeObject
Constructor: private
Singleton: No
Namespace: tabris
Direct subclasses: None
JSX Support: No

Examples

JavaScript

import {device} from 'tabris';

const camera = device.cameras[0];
camera.active = true;

camera.captureImage()
  .then(({image}) => console.log(`Captured image with size ${image.size}.`));

See also:

JSX Simple example to capture an image
TSX Control Camera and CameraView to capture an image
JSX Check and request camera permissions

Methods

captureImage(options?)

Captures an image and returns a result object when the returned promise resolves successfully. The Camera has to be in an active state to capture an image. The result object has an image property of type Blob which contains the jpg encoded image, as well as a width and height property describing the dimensions of the captured image.

Parameter Type Description
options {
  flash: 'auto' | 'on' | 'off' // Whether to enable or disable the device flashlight. If set to `'auto'` the device will decide (based on the lighting conditions) whether to activate the flashlight. defaults to off
}
A set of capture options to apply when taking a picture. Optional.

Returns: Promise<{image: Blob, width: number, height: number}>

Properties

active

Setting active to true activates the camera. If it is currently assigned to a CameraView, the CameraView will now show the video feed from the Camera. It is then possible to capture an image via the captureImage() method.

Setting active to false stops the camera and disables any video feed shown on a CameraView.

It is recommended to stop the Camera when not in use in order to preserve battery life.

Type: boolean
Default: false
Settable: Yes
Change Event: activeChanged

availableCaptureResolutions

An array of resolutions supported by the camera. Each array entry is an object consisting of width and height. Eg.: `{width: 4000, height: 3000}

Type: Array<{width: number, height: number}>
Settable: No
Change Event: availableCaptureResolutionsChanged

cameraId

The id of the device camera given by the native platform.

Type: string
Settable: No
Change Event: Not supported

This property can only be set via constructor. Once set, it cannot change anymore.

captureResolution

An object determining the pixel dimensions of the captured image. Has to be an object containing width and height properties of type number. The list of natively available resolutions can be obtained from the availableCaptureResolutions property.

If the given captureResolution is not in the list of availableCaptureResolutions, a closely matching resolution larger than the given resolution is used. When no captureResolution is given (value is null), the best possible match for the device is chosen automatically. The physical dimensions of the captured image should be checked on the resolved result object of the captureImage() method.

When setting the captureResolution on the iOS platform, a small grace period should pass before capturing an image. Otherwise the image might turn out incorrectly exposed.

Type: {width: number, height: number}
Settable: Yes
Change Event: captureResolutionChanged

position

The position of the camera on the device. The external position is used for devices like usb cameras.

Type: 'front'
| 'back'
| 'external'
Settable: No
Change Event: Not supported

This property can only be set via constructor. Once set, it cannot change anymore.

Change Events

activeChanged

Fired when the active property has changed.

EventObject Type: PropertyChangedEvent<Camera, boolean>

Property Type Description
value boolean The new value of active.

availableCaptureResolutionsChanged

Fired when the availableCaptureResolutions property has changed.

EventObject Type: PropertyChangedEvent<Camera, Array>

Property Type Description
value Array<{width: number, height: number}> The new value of availableCaptureResolutions.

captureResolutionChanged

Fired when the captureResolution property has changed.

EventObject Type: PropertyChangedEvent<Camera, Object>

Property Type Description
value {width: number, height: number} The new value of captureResolution.