Archive Expo Snack Discord Forums Changelog

Expo Camera
GitHub
npm

expo-camera provides a React component that renders a preview of the device's front or back camera. The camera's parameters like zoom, auto focus, white balance and flash mode are adjustable. With the use of Camera, one can also take photos and record videos that are then saved to the app's cache. The component is also capable of detecting faces and bar codes appearing in the preview. Run the example on your device to see all these features working together.

Platform Compatibility

Android Device	Android Emulator	iOS Device	iOS Simulator	Web

Android devices can use one of two available Camera APIs: you can opt-in to using Camera2 with the useCamera2Api prop.

Installation

Terminal

- npx expo install expo-camera

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Configuration in app.json/app.config.js

You can configure expo-camera using its built-in config plugin if you use config plugins in your project (EAS Build or npx expo run:[android|ios]). The plugin allows you to configure various properties that cannot be set at runtime and require building a new app binary to take effect.

Example app.json with config plugin

app.json

{
  "expo": {
    "plugins": [
      [
        "expo-camera",
        {
          "cameraPermission": "Allow $(PRODUCT_NAME) to access your camera."
        }
      ]
    ]
  }
}

Configurable properties

Name	Default	Description
`cameraPermission`	`"Allow $(PRODUCT_NAME) to access your camera"`	Only for: iOS A string to set the `NSCameraUsageDescription` permission message.
`microphonePermission`	`"Allow $(PRODUCT_NAME) to access your microphone"`	Only for: iOS A string to set the `NSMicrophoneUsageDescription` permission message.

Are you using this library in a bare React Native app?

Learn how to configure the native projects in the installation instructions in the expo-camera repository.

Usage

Only one Camera preview can be active at any given time. If you have multiple screens in your app, you should unmount Camera components whenever a screen is unfocused.

Basic Camera usage

import { Camera, CameraType } from 'expo-camera';
import { useState } from 'react';
import { Button, StyleSheet, Text, TouchableOpacity, View } from 'react-native';

export default function App() {
  const [type, setType] = useState(CameraType.back);
  const [permission, requestPermission] = Camera.useCameraPermissions();

  %%placeholder-start%%if (!permission) ... %%placeholder-end%%if (!permission) {
    // Camera permissions are still loading
    return <View />;
  }

  %%placeholder-start%%if (!permission.granted) ... %%placeholder-end%%if (!permission.granted) {
    // Camera permissions are not granted yet
    return (
      <View style={styles.container}>
        <Text style={{ textAlign: 'center' }}>We need your permission to show the camera</Text>
        <Button onPress={requestPermission} title="grant permission" />
      </View>
    );
  }

  function toggleCameraType() {
    setType(current => (current === CameraType.back ? CameraType.front : CameraType.back));
  }

  return (
    <View style={styles.container}>
      <Camera style={styles.camera} type={type}>
        <View style={styles.buttonContainer}>
          <TouchableOpacity style={styles.button} onPress={toggleCameraType}>
            <Text style={styles.text}>Flip Camera</Text>
          </TouchableOpacity>
        </View>
      </Camera>
    </View>
  );
}

%%placeholder-start%%const styles = StyleSheet.create({ ... }); %%placeholder-end%%const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
  },
  camera: {
    flex: 1,
  },
  buttonContainer: {
    flex: 1,
    flexDirection: 'row',
    backgroundColor: 'transparent',
    margin: 64,
  },
  button: {
    flex: 1,
    alignSelf: 'flex-end',
    alignItems: 'center',
  },
  text: {
    fontSize: 24,
    fontWeight: 'bold',
    color: 'white',
  },
});

Web Support

Luckily most browsers support at least some form of web camera functionality, you can check out the web camera browser support here. Image URIs are always returned as base64 strings because local file system paths are not available in the browser.

Chrome `iframe` usage

When using Chrome versions 64+, if you try to use a web camera in a cross-origin iframe nothing will render. To add support for cameras in your iframe simply add the attribute allow="microphone; camera;" to the iframe element:

<iframe src="..." allow="microphone; camera;">
  <!-- <Camera /> -->
</iframe>

API

import { Camera } from 'expo-camera';

Component

`Camera`

Type: React.Component<CameraProps>

Props

`autoFocus`

Optional • Type: boolean | number | AutoFocus • Default: AutoFocus.on

State of camera auto focus. Use one of AutoFocus.<value>. When AutoFocus.on, auto focus will be enabled, when AutoFocus.off, it won't and focus will lock as it was in the moment of change, but it can be adjusted on some devices via focusDepth prop.

`barCodeScannerSettings`

Optional • Type: BarCodeSettings

Settings exposed by BarCodeScanner module. Supported settings: barCodeTypes.

Example

<Camera
  barCodeScannerSettings={{
    barCodeTypes: [BarCodeScanner.Constants.BarCodeType.qr],
  }}
/>

`faceDetectorSettings`

Optional • Type: object

A settings object passed directly to an underlying module providing face detection features. See DetectionOptions in FaceDetector documentation for details.

`flashMode`

Optional • Type: number | FlashMode • Default: FlashMode.off

Camera flash mode. Use one of FlashMode.<value>. When FlashMode.on, the flash on your device will turn on when taking a picture, when FlashMode.off, it won't. Setting to FlashMode.auto will fire flash if required, FlashMode.torch turns on flash during the preview.

`focusDepth`

Optional • Type: number • Default: 0

Distance to plane of the sharpest focus. A value between 0 and 1 where: 0 - infinity focus, 1 - focus as close as possible. For Android this is available only for some devices and when useCamera2Api is set to true.

`onBarCodeScanned`

Optional • Type: (scanningResult: BarCodeScanningResult) => void

Callback that is invoked when a bar code has been successfully scanned. The callback is provided with an object of the BarCodeScanningResult shape, where the type refers to the bar code type that was scanned and the data is the information encoded in the bar code (in this case of QR codes, this is often a URL). See BarCodeScanner.Constants.BarCodeType for supported values.

`onCameraReady`

Optional • Type: () => void

Callback invoked when camera preview has been set.

`onFacesDetected`

Optional • Type: (faces: FaceDetectionResult) => void

Callback invoked with results of face detection on the preview. See DetectionResult in FaceDetector documentation for more details.

`onMountError`

Optional • Type: (event: CameraMountError) => void

Callback invoked when camera preview could not been started.

`pictureSize`

Optional • Type: string

A string representing the size of pictures takePictureAsync will take. Available sizes can be fetched with getAvailablePictureSizesAsync.

Only for:

Web

`poster`

Optional • Type: string

A URL for an image to be shown while the camera is loading.

Only for:

Android

`ratio`

Optional • Type: string • Default: 4:3

A string representing aspect ratio of the preview, eg. 4:3, 16:9, 1:1. To check if a ratio is supported by the device use getSupportedRatiosAsync.

`type`

Optional • Type: number | CameraType • Default: CameraType.back

Camera facing. Use one of CameraType. When CameraType.front, use the front-facing camera. When CameraType.back, use the back-facing camera.

Only for:

Android

`useCamera2Api`

Optional • Type: boolean

Whether to use Android's Camera2 API. See Note at the top of this page.

Only for:

iOS

`videoStabilizationMode`

Optional • Type: VideoStabilization

The video stabilization mode used for a video recording. Use one of VideoStabilization.<value>. You can read more about each stabilization type in Apple Documentation.

`whiteBalance`

Optional • Type: number | WhiteBalance • Default: WhiteBalance.auto

Camera white balance. Use one of WhiteBalance.<value>. If a device does not support any of these values previous one is used.

`zoom`

Optional • Type: number • Default: 0

A value between 0 and 1 being a percentage of device's max zoom. 0 - not zoomed, 1 - maximum zoom.

Inherited Props

ViewProps

Static Methods

Only for:

Web

`getAvailableCameraTypesAsync()`

Returns a list of camera types ['front', 'back']. This is useful for desktop browsers which only have front-facing cameras.

Returns

Promise<CameraType[]>

Only for:

iOS

`getAvailableVideoCodecsAsync()`

Queries the device for the available video codecs that can be used in video recording.

Returns

Promise<VideoCodec[]>

A promise that resolves to a list of strings that represents available codecs.

Only for:

Web

`isAvailableAsync()`

Check whether the current device has a camera. This is useful for web and simulators cases. This isn't influenced by the Permissions API (all platforms), or HTTP usage (in the browser). You will still need to check if the native permission has been accepted.

Returns

Promise<boolean>

Component Methods

`getAvailablePictureSizesAsync(ratio)`

Name	Type	Description
ratio (optional)	`string`	A string representing aspect ratio of sizes to be returned.

Get picture sizes that are supported by the device for given ratio.

Returns

Promise<string[]>

Returns a Promise that resolves to an array of strings representing picture sizes that can be passed to pictureSize prop. The list varies across Android devices but is the same for every iOS.

Only for:

Android

`getSupportedRatiosAsync()`

Get aspect ratios that are supported by the device and can be passed via ratio prop.

Returns

Promise<string[]>

Returns a Promise that resolves to an array of strings representing ratios, eg. ['4:3', '1:1'].

`pausePreview()`

Pauses the camera preview. It is not recommended to use takePictureAsync when preview is paused.

Returns

void

Only for:

Android

iOS

`recordAsync(options)`

Name	Type	Description
options (optional)	`CameraRecordingOptions`	A map of `CameraRecordingOptions` type.

Starts recording a video that will be saved to cache directory. Videos are rotated to match device's orientation. Flipping camera during a recording results in stopping it.

Returns

Promise<{ uri: string }>

Returns a Promise that resolves to an object containing video file uri property and a codec property on iOS. The Promise is returned if stopRecording was invoked, one of maxDuration and maxFileSize is reached or camera preview is stopped.

`resumePreview()`

Resumes the camera preview.

Returns

void

`stopRecording()`

Stops recording if any is in progress.

Returns

void

`takePictureAsync(options)`

Name	Type	Description
options (optional)	`CameraPictureOptions`	An object in form of `CameraPictureOptions` type.

Takes a picture and saves it to app's cache directory. Photos are rotated to match device's orientation (if options.skipProcessing flag is not enabled) and scaled to match the preview. Anyway on Android it is essential to set ratio prop to get a picture with correct dimensions.

Note: Make sure to wait for the onCameraReady callback before calling this method.

Returns

Promise<CameraCapturedPicture>

Returns a Promise that resolves to CameraCapturedPicture object, where uri is a URI to the local image file on iOS, Android, and a base64 string on web (usable as the source for an Image element). The width and height properties specify the dimensions of the image. base64 is included if the base64 option was truthy, and is a string containing the JPEG data of the image in Base64--prepend that with 'data:image/jpg;base64,' to get a data URI, which you can use as the source for an Image element for example. exif is included if the exif option was truthy, and is an object containing EXIF data for the image--the names of its properties are EXIF tags and their values are the values for those tags.

On native platforms, the local image URI is temporary. Use FileSystem.copyAsync to make a permanent copy of the image.

Hooks

`useCameraPermissions(options)`

Name	Type	Description
options (optional)	`PermissionHookOptions<object>`	-

Check or request permissions to access the camera. This uses both requestCameraPermissionsAsync and getCameraPermissionsAsync to interact with the permissions.

Example

const [status, requestPermission] = Camera.useCameraPermissions();

Returns

[null | PermissionResponse, RequestPermissionMethod<PermissionResponse>, GetPermissionMethod<PermissionResponse>]

`useMicrophonePermissions(options)`

Name	Type	Description
options (optional)	`PermissionHookOptions<object>`	-

Check or request permissions to access the microphone. This uses both requestMicrophonePermissionsAsync and getMicrophonePermissionsAsync to interact with the permissions.

Example

const [status, requestPermission] = Camera.useMicrophonePermissions();

Returns

[null | PermissionResponse, RequestPermissionMethod<PermissionResponse>, GetPermissionMethod<PermissionResponse>]

Methods

`Camera.getCameraPermissionsAsync()`

Checks user's permissions for accessing camera.

Returns

Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

`Camera.getMicrophonePermissionsAsync()`

Checks user's permissions for accessing microphone.

Returns

Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

Deprecated. Use getCameraPermissionsAsync or getMicrophonePermissionsAsync instead. Checks user's permissions for accessing camera.

`Camera.getPermissionsAsync()`

Returns

Promise<PermissionResponse>

`Camera.requestCameraPermissionsAsync()`

Asks the user to grant permissions for accessing camera. On iOS this will require apps to specify an NSCameraUsageDescription entry in the Info.plist.

Returns

Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

`Camera.requestMicrophonePermissionsAsync()`

Asks the user to grant permissions for accessing the microphone. On iOS this will require apps to specify an NSMicrophoneUsageDescription entry in the Info.plist.

Returns

Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

Deprecated. Use requestCameraPermissionsAsync or requestMicrophonePermissionsAsync instead.

`Camera.requestPermissionsAsync()`

Asks the user to grant permissions for accessing camera. On iOS this will require apps to specify both NSCameraUsageDescription and NSMicrophoneUsageDescription entries in the Info.plist.

Returns

Promise<PermissionResponse>

A promise that resolves to an object of type PermissionResponse.

Interfaces

`PermissionResponse`

An object obtained by permissions get and request functions.

PermissionResponse Properties

Name	Type	Description
canAskAgain	`boolean`	Indicates if user can be asked again for specific permission. If not, one should be directed to the Settings app in order to enable/disable the permission.
expires	`PermissionExpiration`	Determines time when the permission expires.
granted	`boolean`	A convenience boolean that indicates if the permission is granted.
status	`PermissionStatus`	Determines the status of the permission.

Types

`BarCodeBounds`

Name	Type	Description
origin	`BarCodePoint`	The origin point of the bounding box.
size	`BarCodeSize`	The size of the bounding box.

`BarCodePoint`

Type: Point

These coordinates are represented in the coordinate space of the camera source (e.g. when you are using the camera view, these values are adjusted to the dimensions of the view).

`BarCodeScanningResult`

Name	Type	Description
bounds	`BarCodeBounds`	The BarCodeBounds object. `bounds` in some case will be representing an empty rectangle. Moreover, `bounds` doesn't have to bound the whole barcode. For some types, they will represent the area used by the scanner.
cornerPoints	`BarCodePoint[]`	Corner points of the bounding box. `cornerPoints` is not always available and may be empty. On iOS, for `code39` and `pdf417` you don't get this value.
data	`string`	The information encoded in the bar code.
type	`string`	The barcode type.

`BarCodeSettings`

Name	Type	Description
barCodeTypes	`string[]`	-
interval (optional)	`number`	-

`BarCodeSize`

Name	Type	Description
height	`number`	The height value.
width	`number`	The width value.

`CameraCapturedPicture`

Name	Type	Description
base64 (optional)	`string`	A Base64 representation of the image.
exif (optional)	`Partial<MediaTrackSettings> \| any`	On Android and iOS this object may include various fields based on the device and operating system. On web, it is a partial representation of the `MediaTrackSettings` dictionary.
height	`number`	Captured image height.
uri	`string`	On web, the value of `uri` is the same as `base64` because file system URLs are not supported in the browser.
width	`number`	Captured image width.

`CameraMountError`

Name	Type	Description
message	`string`	-

`CameraPictureOptions`

Name	Type	Description
additionalExif (optional)	`undefined`	Only for: Android iOS Additional EXIF data to be included for the image. Only useful when `exif` option is set to `true`.
base64 (optional)	`boolean`	Whether to also include the image data in Base64 format.
exif (optional)	`boolean`	Whether to also include the EXIF data for the image.
imageType (optional)	`ImageType`	-
isImageMirror (optional)	`boolean`	-
onPictureSaved (optional)	`(picture: CameraCapturedPicture) => void`	-
quality (optional)	`number`	Specify the quality of compression, from 0 to 1. 0 means compress for small size, 1 means compress for maximum quality.
scale (optional)	`number`	-
skipProcessing (optional)	`boolean`	If set to `true`, camera skips orientation adjustment and returns an image straight from the device's camera. If enabled, `quality` option is discarded (processing pipeline is skipped as a whole). Although enabling this option reduces image delivery time significantly, it may cause the image to appear in a wrong orientation in the `Image` component (at the time of writing, it does not respect EXIF orientation of the images). Note: Enabling `skipProcessing` would cause orientation uncertainty. `Image` component does not respect EXIF stored orientation information, that means obtained image would be displayed wrongly (rotated by 90°, 180° or 270°). Different devices provide different orientations. For example some Sony Xperia or Samsung devices don't provide correctly oriented images by default. To always obtain correctly oriented image disable `skipProcessing` option.

`CameraRecordingOptions`

Name	Type	Description
codec (optional)	`VideoCodec`	Only for: iOS This option specifies what codec to use when recording the video. See `VideoCodec` for the possible values.
maxDuration (optional)	`number`	Maximum video duration in seconds.
maxFileSize (optional)	`number`	Maximum video file size in bytes.
mirror (optional)	`boolean`	Only for: iOS If `true`, the recorded video will be flipped along the vertical axis. iOS flips videos recorded with the front camera by default, but you can reverse that back by setting this to `true`. On Android, this is handled in the user's device settings.
mute (optional)	`boolean`	If present, video will be recorded with no sound.
quality (optional)	`number \| string`	Specify the quality of recorded video. Use one of `VideoQuality.<value>`. Possible values: for 16:9 resolution `2160p`, `1080p`, `720p`, `480p` : `Android only` and for 4:3 `4:3` (the size is 640x480). If the chosen quality is not available for a device, the highest available is chosen.
videoBitrate (optional)	`number`	Only for: Android Only works if `useCamera2Api` is set to `true`. This option specifies a desired video bitrate. For example, `510001000` would be 5Mbps.

`FaceDetectionResult`

Name	Type	Description
faces	`object[]`	Array of objects representing results of face detection. See `FaceFeature` in FaceDetector documentation for more details.

`PermissionExpiration`

Permission expiration time. Currently, all permissions are granted permanently.

Acceptable values are: 'never', number.

`PermissionHookOptions`

Acceptable values are: PermissionHookBehavior, Options.

`Point`

Name	Type	Description
x	`number`	-
y	`number`	-

Enums

`AutoFocus`

Only for:

Web

`auto`

AutoFocus.auto ＝ "auto"

`off`

AutoFocus.off ＝ "off"

`on`

AutoFocus.on ＝ "on"

Only for:

Web

`singleShot`

AutoFocus.singleShot ＝ "singleShot"

`CameraType`

`back`

CameraType.back ＝ "back"

`front`

CameraType.front ＝ "front"

`FlashMode`

`auto`

FlashMode.auto ＝ "auto"

`off`

FlashMode.off ＝ "off"

`on`

FlashMode.on ＝ "on"

`torch`

FlashMode.torch ＝ "torch"

`ImageType`

`jpg`

ImageType.jpg ＝ "jpg"

`png`

ImageType.png ＝ "png"

`PermissionStatus`

`DENIED`

PermissionStatus.DENIED ＝ "denied"

User has denied the permission.

`GRANTED`

PermissionStatus.GRANTED ＝ "granted"

User has granted the permission.

`UNDETERMINED`

PermissionStatus.UNDETERMINED ＝ "undetermined"

User hasn't granted or denied the permission yet.

Only for:

iOS

`VideoCodec`

This option specifies what codec to use when recording a video.

`AppleProRes4444`

VideoCodec.AppleProRes4444 ＝ "ap4h"

`AppleProRes422`

VideoCodec.AppleProRes422 ＝ "apcn"

`H264`

VideoCodec.H264 ＝ "avc1"

`HEVC`

VideoCodec.HEVC ＝ "hvc1"

`JPEG`

VideoCodec.JPEG ＝ "jpeg"

`VideoQuality`

`1080p`

VideoQuality.1080p ＝ "1080p"

`2160p`

VideoQuality.2160p ＝ "2160p"

`4:3`

VideoQuality.4:3 ＝ "4:3"

`480p`

VideoQuality.480p ＝ "480p"

`720p`

VideoQuality.720p ＝ "720p"

Only for:

iOS

`VideoStabilization`

This option specifies the stabilization mode to use when recording a video.

`auto`

VideoStabilization.auto ＝ "auto"

`cinematic`

VideoStabilization.cinematic ＝ "cinematic"

`off`

VideoStabilization.off ＝ "off"

`standard`

VideoStabilization.standard ＝ "standard"

`WhiteBalance`

`auto`

WhiteBalance.auto ＝ "auto"

Only for:

Android

iOS

`cloudy`

WhiteBalance.cloudy ＝ "cloudy"

Only for:

Web

`continuous`

WhiteBalance.continuous ＝ "continuous"

Only for:

Android

iOS

`fluorescent`

WhiteBalance.fluorescent ＝ "fluorescent"

Only for:

Android

iOS

`incandescent`

WhiteBalance.incandescent ＝ "incandescent"

Only for:

Web

`manual`

WhiteBalance.manual ＝ "manual"

Only for:

Android

iOS

`shadow`

WhiteBalance.shadow ＝ "shadow"

Only for:

Android

iOS

Android Permission	Description
`CAMERA`	Required to be able to access the camera device.
`RECORD_AUDIO`	Allows an application to record audio.

iOS

The following usage description keys are used by this library:

Info.plist Key	Description
`NSCameraUsageDescription`	A message that tells the user why the app is requesting access to the device’s camera.
`NSMicrophoneUsageDescription`	A message that tells the user why the app is requesting access to the device’s microphone.