Web-gPhoto2

A gPhoto2 implementation using WebAssembly to control DSLR cameras from the browser.

Powered by a custom fork of libgphoto2, the WebUSB backend of libusb, and WebAssembly via Emscripten.

Installation

npm install web-gphoto2

Usage

A short example on how to use this package:

import { Camera } from "web-gphoto2";

let camera = new Camera();

// Triggers the browser's native USB picker listing all connected cameras.
await Camera.showPicker();

// Connects to the camera exposed in the previous step.
// In the future we might allow to connect to multiple cameras by passing a specific instance.
await camera.connect();

console.log("Operations supported by the camera:", await camera.getSupportedOps());

console.log("Current configuration tree:", await camera.getConfig());

// Update camera configuration by the setting's name.
await camera.setConfigValue("iso", "800");

// Capture a lower-quality preview frame, useful for high-FPS live view stream.
// Returns a Blob with image mime type and contents.
const blob = await camera.capturePreviewAsBlob();
// Use `URL.createObjectURL` to create an image URL from the blob or `createImageBitmap` to decode it directly.
const img = new Image();
img.src = URL.createObjectURL(blob);

// Capture a full-resolution image in format currently selected on the camera (JPEG or RAW).
// This can be used in the same way as Blob above, but also has extra information such as filename useful for download.
const file = await camera.captureImageAsFile();
const a = document.createElement("a");
a.href = URL.createObjectURL(file);
a.download = file.name;

Demo

This repository also contains a demo app running gPhoto2 on the Web:

For the detailed technical write-up, see the official blog post. To see the demo in action, visit the hosted version here (but make sure to read the cross-platform compatibility notes first).

If you don't have a DSLR, you can check out a recording of the demo below:

https://user-images.githubusercontent.com/557590/152155035-a1664656-a7d9-411f-8cb3-5f04320f1391.mp4

Building

To build the WebAssembly part of the repo, you'll need Docker on Linux (WSL works too) or macOS machine. Then:

npm run build:wasm # runs build in Docker

If you are just updating the JS library (src/camera.ts), then it's enough to do

npm run build:ts

on any system as Wasm parts are committed to this repo.

To serve the demo, run:

npx serve examples/preact # starts a local server with COOP/COEP

Then, navigate to http://localhost:3000/ in Chrome.

Common Issues

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

Information from Stackoverflow

In vite, both of the above mentioned issues are solved by adding the following to your vite.config.js:

import { sveltekit } from "@sveltejs/kit/vite";
import { defineConfig } from "vite";

/** @type {import('vite').Plugin} */
const viteServerConfig = {
  name: "add headers",
  configureServer: (server) => {
    server.middlewares.use((req, res, next) => {
      res.setHeader("Cross-Origin-Opener-Policy", "same-origin");
      res.setHeader("Cross-Origin-Embedder-Policy", "require-corp");
      next();
    });
  },
};

export default defineConfig({
  plugins: [sveltekit(), viteServerConfig],
  optimizeDeps: {
    exclude: ["web-gphoto2"],
  },
});

See also

RReverser/eos-remote-web - my other project for controlling Canon cameras over Web Bluetooth.

License

Like the dependencies, this demo is licensed under LGPL v2.1.