Vue Qrcode Reader

# QrcodeDropZone

# Browser Support

The newest API this component depend on is the FileReader API. Vue Native is not supported (see #206).

Internet Explorer Edge Firefox Chrome Safari
10+ Yes Yes Yes Yes

# Events

# decode

  • Payload Type: String

You can drag-and-drop image files from your desktop or images embedded into other web pages anywhere in the area the component occupies. The images are directly scanned and positive results are indicated by the decode event. You can also drop multiple images at the same time (still one event per image though).

However, if no QR code is pictured or an error occurs, decode silently fails.

<qrcode-drop-zone @decode="onDecode">
   <!-- ... -->
</qrcode-drop-zone>

methods: {
  onDecode (decodedString) {
    // ...
  }
}

# detect

  • Payload Type: Promise<Object>

The detect event is basically a verbose version of decode. detect is emitted as soon as you drop an image. It carries a Promise which resolves when scanning the dropped image has finished. The Promise rejects in case of errors. Additionally, detect gives you the unprocessed raw image data and the coordinates of the QR code in the image.

<qrcode-drop-zone @detect="onDetect">
   <!-- ... -->
</qrcode-drop-zone>

methods: {
  async onDetect (promise) {
    try {
      const {
        imageData,    // raw image data of image/frame
        content,      // decoded String or null
        location      // QR code coordinates or null
      } = await promise

      if (content === null) {
         // decoded nothing
      } else {
         // ...
      }
    } catch (error) {
      if (error.name === 'DropImageFetchError') {
        // drag-and-dropped URL (probably just an <img> element) from different
        // domain without CORS header caused same-origin-policy violation
      } else if (error.name === 'DropImageDecodeError') {
        // drag-and-dropped file is not of type image and can't be decoded
      } else {
        // idk, open an issue ¯\_(ツ)_/¯
      }
    }
  }
}

# dragover

  • Payload Type: Boolean

When the user is dragging something over the the component you might want to apply some emphasizing styling. Do that by reacting to the dragover event.

<qrcode-drop-zone @dragover="onDragOver">
  <div :class="{ highlight: draggingOver }">
    <!-- ... -->
  </div>
</qrcode-drop-zone>

data () {
  return {
    draggingOver: false
  }
},

methods: {
  onDragOver (draggingOver) {
    this.draggingOver = draggingOver
  }
}

WARNING

This is a custom event not to be confused with native dragover. If you really need to listen for the DOM event instead, use Vues native event modifier.

# Props

no props

# Slots

# default

This component merely renders a wrapper div. Its height is defined by the content inside so it will have zero height if you don't provide any content.

<qrcode-drop-zone>
  <b>put anything here</b>
</qrcode-drop-zone>

← QrcodeCapture →