@castlenine/svelte-qrcode

QR Code generator for Svelte & SvelteKit, with no dependencies

Install

Use your package manager to install:

npm install --save-dev @castlenine/svelte-qrcode

Quick Start

<script>
  import QRCode from '@castlenine/svelte-qrcode';
</script>

<QRCode data="Hello world!" />

Migration from v1 to v2

Many new features have been added to version 2.0.0, and some properties have been renamed.

Here is a list of the changes:

Old property name	New property name	Note
content	data
errorCorrection	errorCorrectionLevel
base64Image	logoInBase64
logoWidth	logoSize	logoSize is applied to logoWidth and logoHeight (new property)
dispatchDownloadLink	dispatchDownloadUrl

Old event name	New event name
downloadLinkGenerated	downloadUrlGenerated

Properties

Data

The data encoded in the QR code typically consists of a URL to a website or a code used by applications, such as handling secrets in time-based one-time password (TOTP) applications.

This is the only property required to generate the QR code.

Property name	Type	Required
data	string	Yes

<QRCode data="https://duxreserve.com" />

QR Code type number

The QR code type number, an integer ranging from 1 to 40, determines the QR code's data capacity. The default value is 0, which allows for automatic detection.

More details

Property name	Type	Default value
typeNumber	Integer number between 0 and 40	0

Note: In most cases, setting this property is unnecessary. However, if you need to generate a QR code with a specific type number, you can set it as follows:

<QRCode data="https://duxreserve.com" typeNumber={4} />

Error correction level

QR Code has error correction capability to restore data if the code is dirty or damaged. Four error correction levels are available to choose according to the operating environment. Raising this level improves error correction capability but also increases the amount of data QR Code size and reduces the QR code's data capacity.

To select error correction level, various factors such as the operating environment and QR Code size need to be considered. Level Q or H may be selected for factory environment where QR Code get dirty, whereas Level L may be selected for a clean environment with the large amount of data. Typically, level M (15%) is most frequently selected.

• Level L Approx 7%
• Level M Approx 15% (default value)
• Level Q Approx 25%
• Level H Approx 30%

Property name	Type	Default value
errorCorrectionLevel	'L', 'M', 'Q', 'H'	'M'

<QRCode data="https://duxreserve.com" errorCorrectionLevel="L" />

<QRCode data="https://duxreserve.com" errorCorrectionLevel="M" />

<QRCode data="https://duxreserve.com" errorCorrectionLevel="Q" />

<QRCode data="https://duxreserve.com" errorCorrectionLevel="H" />

Colors

You can customize the colors of the QR code using hexadecimal color codes or CSS color keywords such as 'transparent' and 'red'.

Property name	Type	Default value	Note
backgroundColor	string	'#ffffff'
color	string	'#000000'	Will be apply to modulesColor,anchorsOuterColor and anchorsInnerColor if they are not defined
modulesColor	string	Same as color property
anchorsOuterColor	string	Same as modulesColor property
anchorsInnerColor	string	Same as anchorsOuterColor property

<QRCode data="https://duxreserve.com" backgroundColor="#009900" color="#ffffff" />

<QRCode data="https://duxreserve.com" backgroundColor="black" modulesColor="#ffffff" anchorsOuterColor="red" anchorsInnerColor="#00ff00" />

Shape

You have two options to customize the QR code shape: 'square' and 'circle'.

Set the haveBackgroundRoundedEdges property to true to round the edges of the QR code background.

Set the haveGappedModules property to true to create gaps between the modules.

Property name	Type	Default value
shape	'square', 'circle'	'square'
haveBackgroundRoundedEdges	boolean	false
haveGappedModules	boolean	false

<!-- No need to set the shape for `square` (default value) -->
<QRCode data="https://duxreserve.com" />

<QRCode data="https://duxreserve.com" shape="circle" />

<QRCode data="https://duxreserve.com" haveBackgroundRoundedEdges />

<QRCode data="https://duxreserve.com" haveGappedModules />

Join in unique SVG element

If isJoin is set to true, the QR code will be generated as a single SVG element. If set to false, each square will be an individual SVG element.

The isJoin property is useful for performance optimization, especially when generating a large number of QR codes. However, the colors of the anchors and modules will not differ, and the shape can only be 'square' when isJoin is set to true.

Note: Most of the cases, you don't need to set this property to true.

Property name	Type	Default value
isJoin	boolean	false

<QRCode data="https://duxreserve.com" isJoin />

Responsive

If isResponsive set to true, the QR code will be responsive and adapt to the available space in its parent element.

Property name	Type	Default value
isResponsive	boolean	false

<div style="width: 30%; height: 30%;">
  <QRCode data="https://duxreserve.com" isResponsive />
</div>

QR Code size

You can adjust the padding and size of the QR code. Increasing the size enhances the ease of scanning.

The padding is measured in "module units", while the size, width and height are in pixels.

Note: It's recommended to use a square-like QR code if you prefer different width and height values. Test the QR code with different sizes to ensure it is scannable.

Property name	Type	Default value	Note
padding	number (module unit)	1 "module unit"	1 padding = 1 module unit
size	number (pixel)	256 pixels	Will be apply to width and height if they are not defined
width	number (pixel)	Same as size property
height	number (pixel)	Same as size property

<QRCode data="https://duxreserve.com" padding={5} size={1000} />

<QRCode data="https://duxreserve.com" padding={5} width={1000} height={800} />

Centered logo

You can add a logo to the center of the QR code; it will be automatically scaled to fit and inserted in the generated SVG.

If you don't set logoInBase64 or logoPath, the logo will not be displayed. You can use either logoPath or logoInBase64 to specify the logo image. Use logoInBase64 instead of logoPath for faster logo loading times. If you use logoInBase64, the logoPath property will be ignored. There is no validation of the base64 encoding for logoInBase64; ensure it is valid.

logoPath can be either a local path or a URL. Typically, the logo file is located in the static folder. If the path is incorrect or undefined, the logo will not be displayed. It uses the Fetch API to load the image; therefore, if the URL is external, it must be CORS-enabled. There may be a slight delay in loading the image when using logoPath. You can set waitForLogo to true to ensure the logo loads before the QR code is rendered.

If you don't set logoBackgroundColor, the logo will have the same background color as the QR code.

Note: There is no validation of the base64 encoding for logoInBase64; ensure it is valid.

Property name	Type	Default value	Note
logoInBase64	base64 (image) string	'' (no logo)
logoPath	string	'' (no logo)
logoBackgroundColor	string	'' (same as the QR Code backgroundColor property)
logoPadding	number (module unit)	1 "module unit"	1 logoPadding = 1 module unit
logoSize	number (pixel)	15% of the QR code size property	Will be apply to logoWidth and logoHeight if they are not defined
logoWidth	number (pixel)	Same as logoSize property
logoHeight	number (pixel)	Same as logoSize property
waitForLogo	boolean	false

<QRCode data="https://duxreserve.com" logoPath="/logo/lightning.svg" />

<!-- External URL -->
<QRCode data="https://duxreserve.com" logoPath="https://upload.wikimedia.org/wikipedia/commons/a/a8/Lightning_bolt_simple.png" />

<!-- WaitForLogo -->
<QRCode data="https://duxreserve.com" logoPath="https://upload.wikimedia.org/wikipedia/commons/a/a8/Lightning_bolt_simple.png" waitForLogo />

<!-- logoInBase64 -->
<QRCode data="https://duxreserve.com" logoInBase64="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIzMiIgaGVpZ2h0PSIzMiIgdmlld0JveD0iMCAwIDI0IDI0Ij48cGF0aCBmaWxsPSJjdXJyZW50Q29sb3IiIGQ9Im0xOC40OTYgMTAuNzA5bC04LjYzNiA4Ljg4Yy0uMjQuMjQ2LS42MzgtLjAzOS0uNDgyLS4zNDVsMy4wNzQtNi4wNjZhLjMuMyAwIDAgMC0uMjY4LS40MzZINS43MThhLjMuMyAwIDAgMS0uMjE0LS41MWw4LjAxLTguMTE1Yy4yMzItLjIzNS42MTguMDIzLjQ4OS4zMjhMMTEuNzA2IDkuODZhLjMuMyAwIDAgMCAuMjguNDE3bDYuMjkxLS4wNzhhLjMuMyAwIDAgMSAuMjIuNTA5Ii8+PC9zdmc+" />

<!-- logo background color -->
<QRCode data="https://duxreserve.com" logoPath="/logo/lightning.svg" logoBackgroundColor="#ff0000" />

<!-- logo padding -->
<QRCode data="https://duxreserve.com" logoPath="/logo/lightning.svg" logoPadding={2} />

<!-- logo size -->
<QRCode data="https://duxreserve.com" logoPath="/logo/lightning.svg" logoSize={20} />

<QRCode data="https://duxreserve.com" logoPath="/logo/lightning.svg" logoWidth={20} logoHeigh={15} />

Downloading the QR Code

You can download the QR code as a file ('svg' | 'png' | 'jpg' | 'jpeg' | 'webp') by using an anchor tag that initiates the download. To enable this functionality, set the dispatchDownloadUrl property to true and listen for the downloadUrlGenerated event to retrieve the download URL. You can choose the file format by setting the downloadUrlFileFormat property to 'svg' (default), 'png', 'jpg', 'jpeg', or 'webp'.

Add the download attribute to the anchor tag to specify the filename for the downloaded file. The extension is optional in the file name; the file format will be determined by the downloadUrlFileFormat property.

Additionally, include the target="_blank" attribute in the anchor tag to open the download in a new tab.

Note: You cannot use the downloadUrlFileFormat other than 'svg' in a non-browser environment.

Property name	Type	Default value
dispatchDownloadUrl	boolean	false
downloadUrlFileFormat	'svg', 'png', 'jpg', 'jpeg', 'webp'	'svg'

<script>
  import QRCode from '@castlenine/svelte-qrcode';

  let downloadUrl = '';

  const handleDownloadUrlGenerated = (url = '') => {
    downloadUrl = url;
  };
</script>

<div>
  <QRCode
    data="https://duxreserve.com"
    logoPath="/logo/lightning.svg"
    downloadUrlFileFormat="png"
    dispatchDownloadUrl
    on:downloadUrlGenerated={(event) => handleDownloadUrlGenerated(event.detail.url)}
  />
</div>


{#if downloadUrl}
  <a href={downloadUrl} download="QR-code-filename.png" target="_blank">Download QR Code</a>
{/if}

Other events

You can listen for the following events:

• qrCodeGenerated: The QR Code is successfully generated
• qrCodeRegeneratedWithLogo: The QR Code is successfully regenerated with the logo
• qrCodeGenerationFailed: The QR Code generation failed. The error message can be retrieved via event.detail. Check the console for more information

<QRCode
  data="https://duxreserve.com"
  on:qrCodeGenerated={handleQrCodeGenerated}
  on:qrCodeRegeneratedWithLogo={handleQrCodeRegeneratedWithLogo}
  on:qrCodeGenerationFailed={handleQrCodeGenerationFailed}
/>

Time-based one-time passwords (TOTP)

Sample URL for a John Doe user on the Acme app:

<QRCode data="otpauth://totp/ACME%20Co:[email protected]?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME%20Co&algorithm=SHA1&digits=6&period=30" />