@undecaf/zbar-wasm
Advanced tools
This project was forked from ZBar.wasm, a WebAssembly build of the ZBar Bar Code Reader written in C/C++.
ImageData and
RGB/grayscale ArrayBuffer objectsA simple example: on GitHub (source code), on CodePen
A polyfill for the BarcodeDetector Web API:
on GitHub
(source code
with build scripts for Rollup and esbuild),
on CodePen
<script type="module">An example that scans a static image file:
<!DOCTYPE html>
<html>
<body>
<img id="img" crossorigin="anonymous" src="https://raw.githubusercontent.com/undecaf/zbar-wasm/master/test/img/qr_code.png">
<pre id="result"></pre>
<script type="module">
import * as zbarWasm from 'https://cdn.jsdelivr.net/npm/@undecaf/zbar-wasm@0.9.16/dist/main.js'
(async () => {
const
img = document.getElementById('img'),
result = document.getElementById('result'),
canvas = document.createElement('canvas'),
context = canvas.getContext('2d');
await img.decode()
canvas.width = img.naturalWidth
canvas.height = img.naturalHeight
context.drawImage(img, 0, 0)
const
imageData = context.getImageData(0, 0, canvas.width, canvas.height),
symbols = await zbarWasm.scanImageData(imageData);
symbols.forEach(s => s.rawData = s.decode())
result.innerText = JSON.stringify(symbols, null, 2)
})()
</script>
</body>
</html>
<script>Almost identical to the snippet above, just replace the lines
⁝
<script type="module">
import * as zbarWasm from 'https://cdn.jsdelivr.net/npm/@undecaf/zbar-wasm@0.9.16/dist/main.js'
⁝
with
⁝
<script src="https://cdn.jsdelivr.net/npm/@undecaf/zbar-wasm@0.9.16/dist/index.js"></script>
<script>
⁝
Installing:
$ npm install @undecaf/zbar-wasm@0.9.16
or
$ yarn add @undecaf/zbar-wasm@0.9.16
Using:
import ... from '@undecaf/zbar-wasm' pulls the ES module from the package,
require('@undecaf/zbar-wasm') pulls the CommonJS module.
Please refer to the API documentation for what can be imported/required.
A simple Node.js example that scans a static image file:
const { createCanvas, loadImage } = require('canvas');
const { scanImageData } = require('@undecaf/zbar-wasm');
(async (url) => {
const
img = await loadImage(url),
canvas = createCanvas(img.width, img.height),
ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0);
const
imageData = ctx.getImageData(0, 0, img.width, img.height),
symbols = await scanImageData(imageData);
console.log(symbols[0].typeName, symbols[0].decode());
}) ('https://raw.githubusercontent.com/undecaf/zbar-wasm/master/test/img/qr_code.png');
zbar-wasm loads the WebAssembly file zbar.wasm at runtime. zbar.wasm must be located in the same directory
as the zbar-wasm <script> or module, be it on a file system or at a remote endpoint.
This must be observed when bundling zbar-wasm or deploying it to a server:
@undecaf/zbar-wasm/dist/zbar.wasm must be copied as-is (e.g. using copy-webpack-plugin,
rollup-plugin-copy, esbuild-plugin-copy
or similar).zbar.wasm must be copied to the directory where the zbar-wasm module/the bundle containing that module is located.application/wasm so that it can be compiled in parallel with being received
by the browser.Owing to the predecessor of this project, samsam2310/zbar.wasm, a wiki and an extensive API Reference are already available. Many thanks to the author!
Please note that a few classes have been renamed compared to the documentation in order to avoid conflicts with built-in JavaScript class names:
Symbol → ZBarSymbolImage → ZBarImageImageScanner → ZBarScannerBarcodeDetector Web APIThe BarcodeDetector polyfill
package (in this repository, by the same author) is based on
zbar-wasm but provides a standardized, higher-level and more flexible API.
Prerequisites:
To build:
$ git clone https://github.com/undecaf/zbar-wasm
$ cd zbar-wasm
$ make
The make command runs emscripten in a container, compiling the C/C++
sources of the ZBar Bar Code Reader
to WebAssembly. It also compiles and bundles the TypeScript glue code
and runs the tests in Node.js on the host machine.
If you prefer Podman as container engine then the provided Makefile needs
to be edited before running make: replace the line
EM_ENGINE = $(EM_DOCKER)
with
EM_ENGINE = $(EM_PODMAN)
Software: LGPL-2.1
Documentation: CC-BY-SA 4.0
FAQs
A WebAssembly build of the C/C++ ZBar barcode reader
The npm package @undecaf/zbar-wasm receives a total of 10,152 weekly downloads. As such, @undecaf/zbar-wasm popularity was classified as popular.
We found that @undecaf/zbar-wasm demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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