expo-camera
Version:
A React component that renders a preview for the device's either front or back camera. Camera's parameters like zoom, auto focus, white balance and flash mode are adjustable. With expo-camera, one can also take photos and record videos that are saved to t
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JavaScript
import { UnavailabilityError } from 'expo-modules-core';
import { PermissionStatus, } from './Camera.types';
import { canGetUserMedia, isBackCameraAvailableAsync, isFrontCameraAvailableAsync, } from './web/WebUserMediaManager';
function getUserMedia(constraints) {
if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
return navigator.mediaDevices.getUserMedia(constraints);
}
// Some browsers partially implement mediaDevices. We can't just assign an object
// with getUserMedia as it would overwrite existing properties.
// Here, we will just add the getUserMedia property if it's missing.
// First get ahold of the legacy getUserMedia, if present
const getUserMedia =
// TODO: this method is deprecated, migrate to https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getUserMedia
navigator.getUserMedia ||
navigator.webkitGetUserMedia ||
navigator.mozGetUserMedia ||
function () {
const error = new Error('Permission unimplemented');
error.code = 0;
error.name = 'NotAllowedError';
throw error;
};
return new Promise((resolve, reject) => {
// TODO(@kitten): The types indicates that this is incorrect.
// Please check whether this is correct!
// @ts-expect-error: The `successCallback` doesn't match a `resolve` function
getUserMedia.call(navigator, constraints, resolve, reject);
});
}
function handleGetUserMediaError({ message }) {
// name: NotAllowedError
// code: 0
if (message === 'Permission dismissed') {
return {
status: PermissionStatus.UNDETERMINED,
expires: 'never',
canAskAgain: true,
granted: false,
};
}
else {
// TODO: Bacon: [OSX] The system could deny access to chrome.
// TODO: Bacon: add: { status: 'unimplemented' }
return {
status: PermissionStatus.DENIED,
expires: 'never',
canAskAgain: true,
granted: false,
};
}
}
async function handleRequestPermissionsAsync() {
try {
const streams = await getUserMedia({
video: true,
});
// We need to close the media stream returned by getUserMedia
// to avoid using the camera since we won't use these streams now
// https://developer.mozilla.org/fr/docs/Web/API/MediaDevices/getUserMedia
streams.getTracks().forEach((track) => {
track.stop();
streams.removeTrack(track);
});
return {
status: PermissionStatus.GRANTED,
expires: 'never',
canAskAgain: true,
granted: true,
};
}
catch (error) {
return handleGetUserMediaError(error.message);
}
}
async function handlePermissionsQueryAsync(query) {
if (!navigator?.permissions?.query) {
throw new UnavailabilityError('expo-camera', 'navigator.permissions API is not available');
}
try {
const { state } = await navigator.permissions.query({ name: query });
switch (state) {
case 'prompt':
return {
status: PermissionStatus.UNDETERMINED,
expires: 'never',
canAskAgain: true,
granted: false,
};
case 'granted':
return {
status: PermissionStatus.GRANTED,
expires: 'never',
canAskAgain: true,
granted: true,
};
case 'denied':
return {
status: PermissionStatus.DENIED,
expires: 'never',
canAskAgain: true,
granted: false,
};
}
}
catch (e) {
// Firefox doesn't support querying for the camera permission, so return undetermined status
if (e instanceof TypeError) {
return {
status: PermissionStatus.UNDETERMINED,
expires: 'never',
canAskAgain: true,
granted: false,
};
}
throw e;
}
}
export default {
get Type() {
return {
back: 'back',
front: 'front',
};
},
get FlashMode() {
return {
on: 'on',
off: 'off',
auto: 'auto',
torch: 'torch',
};
},
get AutoFocus() {
return {
on: 'on',
off: 'off',
auto: 'auto',
singleShot: 'singleShot',
};
},
get WhiteBalance() {
return {
auto: 'auto',
continuous: 'continuous',
manual: 'manual',
};
},
get VideoQuality() {
return {};
},
get VideoStabilization() {
return {};
},
async isAvailableAsync() {
return canGetUserMedia();
},
async takePicture(options, camera) {
return await camera.takePicture(options);
},
async pausePreview(camera) {
await camera.pausePreview();
},
async resumePreview(camera) {
return await camera.resumePreview();
},
async getAvailableCameraTypesAsync() {
if (!canGetUserMedia() || !navigator.mediaDevices.enumerateDevices)
return [];
const devices = await navigator.mediaDevices.enumerateDevices();
const types = await Promise.all([
(await isFrontCameraAvailableAsync(devices)) && 'front',
(await isBackCameraAvailableAsync()) && 'back',
]);
return types.filter(Boolean);
},
async getAvailablePictureSizes(ratio, camera) {
return await camera.getAvailablePictureSizes(ratio);
},
/*
async record(
options?: CameraRecordingOptions,
camera: ExponentCameraRef
): Promise<{ uri: string }> {
// TODO: Support on web
},
async stopRecording(camera: ExponentCameraRef): Promise<void> {
// TODO: Support on web
}, */
async getPermissionsAsync() {
return handlePermissionsQueryAsync('camera');
},
async requestPermissionsAsync() {
return handleRequestPermissionsAsync();
},
async getCameraPermissionsAsync() {
return handlePermissionsQueryAsync('camera');
},
async requestCameraPermissionsAsync() {
return handleRequestPermissionsAsync();
},
async getMicrophonePermissionsAsync() {
return handlePermissionsQueryAsync('microphone');
},
async requestMicrophonePermissionsAsync() {
try {
await getUserMedia({
audio: true,
});
return {
status: PermissionStatus.GRANTED,
expires: 'never',
canAskAgain: true,
granted: true,
};
}
catch (error) {
return handleGetUserMediaError(error.message);
}
},
};
//# sourceMappingURL=ExpoCameraManager.web.js.map