quaggaJS ======== - [Changelog](#changelog) (2017-06-07) - [Browser Support](#browser-support) - [Installing](#installing) - [Getting Started](#gettingstarted) - [API](#api) - [Configuration](#configobject) - [Tips & Tricks](#tipsandtricks) - [Sponsors](#sponsors) ## What is QuaggaJS? QuaggaJS is a barcode-scanner entirely written in JavaScript supporting real- time localization and decoding of various types of barcodes such as __EAN__, __CODE 128__, __CODE 39__, __EAN 8__, __UPC-A__, __UPC-C__, __I2of5__, __2of5__, __CODE 93__ and __CODABAR__. The library is also capable of using `getUserMedia` to get direct access to the user's camera stream. Although the code relies on heavy image-processing even recent smartphones are capable of locating and decoding barcodes in real-time. Try some [examples](https://serratus.github.io/quaggaJS/examples) and check out the blog post ([How barcode-localization works in QuaggaJS][oberhofer_co_how]) if you want to dive deeper into this topic. ![teaser][teaser_left]![teaser][teaser_right] ## Yet another barcode library? This is not yet another port of the great [zxing][zxing_github] library, but more of an extension to it. This implementation features a barcode locator which is capable of finding a barcode-like pattern in an image resulting in an estimated bounding box including the rotation. Simply speaking, this reader is invariant to scale and rotation, whereas other libraries require the barcode to be aligned with the viewport. ## Browser Support Quagga makes use of many modern Web-APIs which are not implemented by all browsers yet. There are two modes in which Quagga operates: 1. analyzing static images and 2. using a camera to decode the images from a live-stream. The latter requires the presence of the MediaDevices API. You can track the compatibility of the used Web-APIs for each mode: - [Static Images](http://caniuse.com/#feat=webworkers,canvas,typedarrays,bloburls,blobbuilder) - [Live Stream](http://caniuse.com/#feat=webworkers,canvas,typedarrays,bloburls,blobbuilder,stream) ### Static Images The following APIs need to be implemented in your browser: - [webworkers](http://caniuse.com/#feat=webworkers) - [canvas](http://caniuse.com/#feat=canvas) - [typedarrays](http://caniuse.com/#feat=typedarrays) - [bloburls](http://caniuse.com/#feat=bloburls) - [blobbuilder](http://caniuse.com/#feat=blobbuilder) ### Live Stream In addition to the APIs mentioned above: - [MediaDevices](http://caniuse.com/#feat=stream) __Important:__ Accessing `getUserMedia` requires a secure origin in most browsers, meaning that `http://` can only be used on `localhost`. All other hostnames need to be served via `https://`. You can find more information in the [Chrome M47 WebRTC Release Notes](https://groups.google.com/forum/#!topic/discuss-webrtc/sq5CVmY69sc). ### Feature-detection of getUserMedia Every browser seems to differently implement the `mediaDevices.getUserMedia` API. Therefore it's highly recommended to include [webrtc-adapter](https://github.com/webrtc/adapter) in your project. Here's how you can test your browser's capabilities: ```javascript if (navigator.mediaDevices && typeof navigator.mediaDevices.getUserMedia === 'function') { // safely access `navigator.mediaDevices.getUserMedia` } ``` The above condition evaluates to: | Browser | result | | ------------- |:-------:| | Edge | `true` | | Chrome | `true` | | Firefox | `true` | | IE 11 | `false` | | Safari iOS | `false` | ## Installing QuaggaJS can be installed using __npm__, __bower__, or by including it with the __script__ tag. ### NPM ```console > npm install quagga ``` And then import it as dependency in your project: ```javascript import Quagga from 'quagga'; // ES6 const Quagga = require('quagga').default; // Common JS (important: default) ``` Currently, the full functionality is only available through the browser. When using QuaggaJS within __node__, only file-based decoding is available. See the example for [node_examples](#node-example). ### Bower You can also install QuaggaJS through __bower__: ```console > bower install quagga ``` ### Script-Tag Anno 1998 You can simply include `dist/quagga.min.js` in your project and you are ready to go. The script exposes the library on the global namespace under `Quagga`. ## Getting Started For starters, have a look at the [examples][github_examples] to get an idea where to go from here. ## Building You can build the library yourself by simply cloning the repo and typing: ```console > npm install > npm run build ``` This npm script builds a non optimized version `quagga.js` and a minified version `quagga.min.js` and places both files in the `dist` folder. Additionally, a `quagga.map` source-map is placed alongside these files. This file is only valid for the non-uglified version `quagga.js` because the minified version is altered after compression and does not align with the map file any more. ### Node The code in the `dist` folder is only targeted to the browser and won't work in node due to the dependency on the DOM. For the use in node, the `build` command also creates a `quagga.js` file in the `lib` folder. ## API You can check out the [examples][github_examples] to get an idea of how to use QuaggaJS. Basically the library exposes the following API: ### Quagga.init(config, callback) This method initializes the library for a given configuration `config` (see below) and invokes the `callback(err)` when Quagga has finished its bootstrapping phase. The initialization process also requests for camera access if real-time detection is configured. In case of an error, the `err` parameter is set and contains information about the cause. A potential cause may be the `inputStream.type` is set to `LiveStream`, but the browser does not support this API, or simply if the user denies the permission to use the camera. If you do not specify a target, QuaggaJS would look for an element that matches the CSS selector `#interactive.viewport` (for backwards compatibility). `target` can be a string (CSS selector matching one of your DOM node) or a DOM node. ```javascript Quagga.init({ inputStream : { name : "Live", type : "LiveStream", target: document.querySelector('#yourElement') // Or '#yourElement' (optional) }, decoder : { readers : ["code_128_reader"] } }, function(err) { if (err) { console.log(err); return } console.log("Initialization finished. Ready to start"); Quagga.start(); }); ``` ### Quagga.start() When the library is initialized, the `start()` method starts the video-stream and begins locating and decoding the images. ### Quagga.stop() If the decoder is currently running, after calling `stop()` the decoder does not process any more images. Additionally, if a camera-stream was requested upon initialization, this operation also disconnects the camera. ### Quagga.onProcessed(callback) This method registers a `callback(data)` function that is called for each frame after the processing is done. The `data` object contains detailed information about the success/failure of the operation. The output varies, depending whether the detection and/or decoding were successful or not. ### Quagga.onDetected(callback) Registers a `callback(data)` function which is triggered whenever a barcode- pattern has been located and decoded successfully. The passed `data` object contains information about the decoding process including the detected code which can be obtained by calling `data.codeResult.code`. ### Quagga.decodeSingle(config, callback) In contrast to the calls described above, this method does not rely on `getUserMedia` and operates on a single image instead. The provided callback is the same as in `onDetected` and contains the result `data` object. ### Quagga.offProcessed(handler) In case the `onProcessed` event is no longer relevant, `offProcessed` removes the given `handler` from the event-queue. ### Quagga.offDetected(handler) In case the `onDetected` event is no longer relevant, `offDetected` removes the given `handler` from the event-queue. ## The result object The callbacks passed into `onProcessed`, `onDetected` and `decodeSingle` receive a `data` object upon execution. The `data` object contains the following information. Depending on the success, some fields may be `undefined` or just empty. ```javascript { "codeResult": { "code": "FANAVF1461710", // the decoded code as a string "format": "code_128", // or code_39, codabar, ean_13, ean_8, upc_a, upc_e "start": 355, "end": 26, "codeset": 100, "startInfo": { "error": 1.0000000000000002, "code": 104, "start": 21, "end": 41 }, "decodedCodes": [{ "code": 104, "start": 21, "end": 41 }, // stripped for brevity { "error": 0.8888888888888893, "code": 106, "start": 328, "end": 350 }], "endInfo": { "error": 0.8888888888888893, "code": 106, "start": 328, "end": 350 }, "direction": -1 }, "line": [{ "x": 25.97278706156836, "y": 360.5616435369468 }, { "x": 401.9220519377024, "y": 70.87524989906444 }], "angle": -0.6565217179979483, "pattern": [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, /* ... */ 1], "box": [ [77.4074243622672, 410.9288668804402], [0.050203235235130705, 310.53619724086366], [360.15706727788256, 33.05711026051813], [437.5142884049146, 133.44977990009465] ], "boxes": [ [ [77.4074243622672, 410.9288668804402], [0.050203235235130705, 310.53619724086366], [360.15706727788256, 33.05711026051813], [437.5142884049146, 133.44977990009465] ], [ [248.90769330706507, 415.2041489551161], [198.9532321622869, 352.62160512937635], [339.546160777576, 240.3979259789976], [389.5006219223542, 302.98046980473737] ] ] } ``` ## Configuration The configuration that ships with QuaggaJS covers the default use-cases and can be fine-tuned for specific requirements. The configuration is managed by the `config` object defining the following high-level properties: ```javascript { numOfWorkers: 4, locate: true, inputStream: {...}, frequency: 10, decoder:{...}, locator: {...}, debug: false, } ``` ### numOfWorkers QuaggaJS supports web-workers out of the box and runs with `4` workers in its default configuration. The number should align with the number of cores available in your targeted devices. In case you don't know the number upfront, or if the variety of devices is too big, you can either use `navigator.hardwareConcurrency` (see [here](https://wiki.whatwg.org/wiki/Navigator_HW_Concurrency)) where available or make use of [core-estimator](https://github.com/oftn/core-estimator). ### locate One of the main features of QuaggaJS is its ability to locate a barcode in a given image. The `locate` property controls whether this feature is turned on (default) or off. Why would someone turn this feature off? Localizing a barcode is a computationally expensive operation and might not work properly on some devices. Another reason would be the lack of auto-focus producing blurry images which makes the localization feature very unstable. However, even if none of the above apply, there is one more case where it might be useful to disable `locate`: If the orientation, and/or the approximate position of the barcode is known, or if you want to guide the user through a rectangular outline. This can increase performance and robustness at the same time. ### inputStream The `inputStream` property defines the sources of images/videos within QuaggaJS. ```javascript { name: "Live", type: "LiveStream", constraints: { width: 640, height: 480, facingMode: "environment", deviceId: "7832475934759384534" }, area: { // defines rectangle of the detection/localization area top: "0%", // top offset right: "0%", // right offset left: "0%", // left offset bottom: "0%" // bottom offset }, singleChannel: false // true: only the red color-channel is read } ``` First, the `type` property can be set to three different values: `ImageStream`, `VideoStream`, or `LiveStream` (default) and should be selected depending on the use-case. Most probably, the default value is sufficient. Second, the `constraint` key defines the physical dimensions of the input image and additional properties, such as `facingMode` which sets the source of the user's camera in case of multiple attached devices. Additionally, if required, the `deviceId` can be set if the selection of the camera is given to the user. This can be easily achieved via [MediaDevices.enumerateDevices()][enumerateDevices] Thirdly, the `area` prop restricts the decoding area of the image. The values are given in percentage, similar to the CSS style property when using `position: absolute`. This `area` is also useful in cases the `locate` property is set to `false`, defining the rectangle for the user. The last key `singleChannel` is only relevant in cases someone wants to debug erroneous behavior of the decoder. If set to `true` the input image's red color-channel is read instead of calculating the gray-scale values of the source's RGB. This is useful in combination with the `ResultCollector` where the gray-scale representations of the wrongly identified images are saved. ### frequency This top-level property controls the scan-frequency of the video-stream. It's optional and defines the maximum number of scans per second. This renders useful for cases where the scan-session is long-running and resources such as CPU power are of concern. ### decoder QuaggaJS usually runs in a two-stage manner (`locate` is set to `true`) where, after the barcode is located, the decoding process starts. Decoding is the process of converting the bars into its true meaning. Most of the configuration options within the `decoder` are for debugging/visualization purposes only. ```javascript { readers: [ 'code_128_reader' ], debug: { drawBoundingBox: false, showFrequency: false, drawScanline: false, showPattern: false } multiple: false } ``` The most important property is `readers` which takes an array of types of barcodes which should be decoded during the session. Possible values are: - code_128_reader (default) - ean_reader - ean_8_reader - code_39_reader - code_39_vin_reader - codabar_reader - upc_reader - upc_e_reader - i2of5_reader - 2of5_reader - code_93_reader Why are not all types activated by default? Simply because one should explicitly define the set of barcodes for their use-case. More decoders means more possible clashes, or false-positives. One should take care of the order the readers are given, since some might return a value even though it is not the correct type (EAN-13 vs. UPC-A). The `multiple` property tells the decoder if it should continue decoding after finding a valid barcode. If multiple is set to `true`, the results will be returned as an array of result objects. Each object in the array will have a `box`, and may have a `codeResult` depending on the success of decoding the individual box. The remaining properties `drawBoundingBox`, `showFrequency`, `drawScanline` and `showPattern` are mostly of interest during debugging and visualization. #### Enabling extended EAN The default setting for `ean_reader` is not capable of reading extensions such as [EAN-2](https://en.wikipedia.org/wiki/EAN_2) or [EAN-5](https://en.wikipedia.org/wiki/EAN_5). In order to activate those supplements you have to provide them in the configuration as followed: ```javascript decoder: { readers: [{ format: "ean_reader", config: { supplements: [ 'ean_5_reader', 'ean_2_reader' ] } }] } ``` Beware that the order of the `supplements` matters in such that the reader stops decoding when the first supplement was found. So if you are interested in EAN-2 and EAN-5 extensions, use the order depicted above. It's important to mention that, if supplements are supplied, regular EAN-13 codes cannot be read any more with the same reader. If you want to read EAN-13 with and without extensions you have to add another `ean_reader` reader to the configuration. ### locator The `locator` config is only relevant if the `locate` flag is set to `true`. It controls the behavior of the localization-process and needs to be adjusted for each specific use-case. The default settings are simply a combination of values which worked best during development. Only two properties are relevant for the use in Quagga (`halfSample` and `patchSize`) whereas the rest is only needed for development and debugging. ```javascript { halfSample: true, patchSize: "medium", // x-small, small, medium, large, x-large debug: { showCanvas: false, showPatches: false, showFoundPatches: false, showSkeleton: false, showLabels: false, showPatchLabels: false, showRemainingPatchLabels: false, boxFromPatches: { showTransformed: false, showTransformedBox: false, showBB: false } } } ``` The `halfSample` flag tells the locator-process whether it should operate on an image scaled down (half width/height, quarter pixel-count ) or not. Turning `halfSample` on reduces the processing-time significantly and also helps finding a barcode pattern due to implicit smoothing. It should be turned off in cases where the barcode is really small and the full resolution is needed to find the position. It's recommended to keep it turned on and use a higher resolution video-image if needed. The second property `patchSize` defines the density of the search-grid. The property accepts strings of the value `x-small`, `small`, `medium`, `large` and `x-large`. The `patchSize` is proportional to the size of the scanned barcodes. If you have really large barcodes which can be read close-up, then the use of `large` or `x-large` is recommended. In cases where the barcode is further away from the camera lens (lack of auto-focus, or small barcodes) then it's advised to set the size to `small` or even `x-small`. For the latter it's also recommended to crank up the resolution in order to find a barcode. ## Examples The following example takes an image `src` as input and prints the result on the console. The decoder is configured to detect _Code128_ barcodes and enables the locating-mechanism for more robust results. ```javascript Quagga.decodeSingle({ decoder: { readers: ["code_128_reader"] // List of active readers }, locate: true, // try to locate the barcode in the image src: '/test/fixtures/code_128/image-001.jpg' // or 'data:image/jpg;base64,' + data }, function(result){ if(result.codeResult) { console.log("result", result.codeResult.code); } else { console.log("not detected"); } }); ``` ### Using node The following example illustrates the use of QuaggaJS within a node environment. It's almost identical to the browser version with the difference that node does not support web-workers out of the box. Therefore the config property `numOfWorkers` must be explicitly set to `0`. ```javascript var Quagga = require('quagga').default; Quagga.decodeSingle({ src: "image-abc-123.jpg", numOfWorkers: 0, // Needs to be 0 when used within node inputStream: { size: 800 // restrict input-size to be 800px in width (long-side) }, decoder: { readers: ["code_128_reader"] // List of active readers }, }, function(result) { if(result.codeResult) { console.log("result", result.codeResult.code); } else { console.log("not detected"); } }); ``` ## Tips & Tricks A growing collection of tips & tricks to improve the various aspects of Quagga. ### Barcodes too small? Barcodes too far away from the camera, or a lens too close to the object result in poor recognition rates and Quagga might respond with a lot of false-positives. Starting in Chrome 59 you can now make use of `capabilities` and directly control the zoom of the camera. Head over to the [web-cam demo](https://serratus.github.io/quaggaJS/examples/live_w_locator.html) and check out the __Zoom__ feature. You can read more about those `capabilities` in [Let's light a torch and explore MediaStreamTrack's capabilities](https://www.oberhofer.co/mediastreamtrack-and-its-capabilities) ### Video too dark? Dark environments usually result in noisy images and therefore mess with the recognition logic. Since Chrome 59 you can turn on/off the __Torch__ of our device and vastly improve the quality of the images. Head over to the [web-cam demo](https://serratus.github.io/quaggaJS/examples/live_w_locator.html) and check out the __Torch__ feature. To find out more about this feature [read on](https://www.oberhofer.co/mediastreamtrack-and-its-capabilities). ## Tests Unit Tests can be run with [Karma][karmaUrl] and written using [Mocha][mochaUrl], [Chai][chaiUrl] and [SinonJS][sinonUrl]. Coverage reports are automatically generated in the coverage/ folder. ```console > npm install > npm run test ``` ## Image Debugging In case you want to take a deeper dive into the inner workings of Quagga, get to know the _debugging_ capabilities of the current implementation. The various flags exposed through the `config` object give you the abilily to visualize almost every step in the processing. Because of the introduction of the web-workers, and their restriction not to have access to the DOM, the configuration must be explicitly set to `config.numOfWorkers = 0` in order to work. ## ResultCollector Quagga is not perfect by any means and may produce false positives from time to time. In order to find out which images produced those false positives, the built-in ``ResultCollector`` will support you and me helping squashing bugs in the implementation. ### Creating a ``ResultCollector`` You can easily create a new ``ResultCollector`` by calling its ``create`` method with a configuration. ```javascript var resultCollector = Quagga.ResultCollector.create({ capture: true, // keep track of the image producing this result capacity: 20, // maximum number of results to store blacklist: [ // list containing codes which should not be recorded {code: "3574660239843", format: "ean_13"}], filter: function(codeResult) { // only store results which match this constraint // returns true/false // e.g.: return codeResult.format === "ean_13"; return true; } }); ``` ### Using a ``ResultCollector`` After creating a ``ResultCollector`` you have to attach it to Quagga by calling ``Quagga.registerResultCollector(resultCollector)``. ### Reading results After a test/recording session, you can now print the collected results which do not fit into a certain schema. Calling ``getResults`` on the ``resultCollector`` returns an ``Array`` containing objects with: ```javascript { codeResult: {}, // same as in onDetected event frame: "data:image/png;base64,iVBOR..." // dataURL of the gray-scaled image } ``` The ``frame`` property is an internal representation of the image and therefore only available in gray-scale. The dataURL representation allows easy saving/rendering of the image. ### Comparing results Now, having the frames available on disk, you can load each single image by calling ``decodeSingle`` with the same configuration as used during recording . In order to reproduce the exact same result, you have to make sure to turn on the ``singleChannel`` flag in the configuration when using ``decodeSingle``. ## Sponsors - [Maintenance Connection Canada (Asset Pro Solutions Inc.](http://maintenanceconnection.ca/) ## Changelog ### 2017-06-07 - Improvements - added `muted` and `playsinline` to `

	Stars	Issues	Version	Updated	Created
@zxing/ngx-scanner			17.0.1	2 months ago	6 years ago
ngx-scanner			0.0.0	5 years ago	5 years ago
qrcode-generator	2,061	51	1.4.4	5 years ago	9 years ago
quagga	4,976	233	0.12.1	7 years ago	9 years ago

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