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
117 lines • 4.55 kB
JavaScript
/* eslint-env browser */
import { canUseDOM } from 'fbjs/lib/ExecutionEnvironment';
export let userMediaRequested = false;
export let mountedInstances = [];
async function requestLegacyUserMediaAsync(props) {
const optionalSource = id => ({ optional: [{ sourceId: id }] });
const constraintToSourceId = constraint => {
const { deviceId } = constraint;
if (typeof deviceId === 'string') {
return deviceId;
}
if (Array.isArray(deviceId) && deviceId.length > 0) {
return deviceId[0];
}
if (typeof deviceId === 'object' && deviceId.ideal) {
return deviceId.ideal;
}
return null;
};
const sources = await new Promise(resolve =>
// @ts-ignore: https://caniuse.com/#search=getSources Chrome for Android (78) & Samsung Internet (10.1) use this
MediaStreamTrack.getSources(sources => resolve(sources)));
let audioSource = null;
let videoSource = null;
sources.forEach(source => {
if (source.kind === 'audio') {
audioSource = source.id;
}
else if (source.kind === 'video') {
videoSource = source.id;
}
});
const audioSourceId = constraintToSourceId(props.audioConstraints);
if (audioSourceId) {
audioSource = audioSourceId;
}
const videoSourceId = constraintToSourceId(props.videoConstraints);
if (videoSourceId) {
videoSource = videoSourceId;
}
return [optionalSource(audioSource), optionalSource(videoSource)];
}
async function sourceSelectedAsync(isMuted, audioConstraints, videoConstraints) {
const constraints = {
video: typeof videoConstraints !== 'undefined' ? videoConstraints : true,
};
if (!isMuted) {
constraints.audio = typeof audioConstraints !== 'undefined' ? audioConstraints : true;
}
return await getAnyUserMediaAsync(constraints);
}
export async function requestUserMediaAsync(props, isMuted = true) {
if (canGetUserMedia()) {
return await sourceSelectedAsync(isMuted, props.audio, props.video);
}
const [audio, video] = await requestLegacyUserMediaAsync(props);
return await sourceSelectedAsync(isMuted, audio, video);
}
export async function getAnyUserMediaAsync(constraints, ignoreConstraints = false) {
try {
return await getUserMediaAsync({
...constraints,
video: ignoreConstraints || constraints.video,
});
}
catch (error) {
if (!ignoreConstraints && error.name === 'ConstraintNotSatisfiedError') {
return await getAnyUserMediaAsync(constraints, true);
}
throw error;
}
}
export async function getUserMediaAsync(constraints) {
if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
return navigator.mediaDevices.getUserMedia(constraints);
}
const _getUserMedia = navigator['mozGetUserMedia'] || navigator['webkitGetUserMedia'] || navigator['msGetUserMedia'];
return new Promise((resolve, reject) => _getUserMedia.call(navigator, constraints, resolve, reject));
}
export function canGetUserMedia() {
return (
// SSR
canUseDOM &&
// Has any form of media API
!!((navigator.mediaDevices && navigator.mediaDevices.getUserMedia) ||
navigator['mozGetUserMedia'] ||
navigator['webkitGetUserMedia'] ||
navigator['msGetUserMedia']));
}
export async function isFrontCameraAvailableAsync(devices) {
return await supportsCameraType(['front', 'user'], 'user', devices);
}
export async function isBackCameraAvailableAsync(devices) {
return await supportsCameraType(['back', 'rear'], 'environment', devices);
}
async function supportsCameraType(labels, type, devices) {
if (!devices) {
if (!navigator.mediaDevices.enumerateDevices) {
return null;
}
devices = await navigator.mediaDevices.enumerateDevices();
}
const cameras = devices.filter(t => t.kind === 'videoinput');
const [hasCamera] = cameras.filter(camera => labels.includes(camera.label.toLowerCase()));
const [isCapable] = cameras.filter(camera => {
if (!('getCapabilities' in camera)) {
return null;
}
const capabilities = camera.getCapabilities();
if (!capabilities.facingMode) {
return null;
}
return capabilities.facingMode.find((_) => type);
});
return isCapable.deviceId || hasCamera.deviceId || null;
}
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