TiddlyWiki5/plugins/tiddlywiki/qrcode/doc/usage.tid

title: $:/plugins/tiddlywiki/qrcode/usage

! `makeqr` Macro

The <<.def makeqr>> [[macro|Macros]] converts text data into an image of the corresponding QR code. The image is returned as [[base64-encoded data URI|https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs]].

!! Parameters

;text
: The text to encode
;size
: The size of the image in pixels (defaults to 500)
;errorCorrectLevel
: Determines the amount of error correction applied to the image; see below (defaults to "M").
;fallback
: The fallback image to be returned in case of an error (see below)

The conversion will fail if the text is too long and/or complex and the macro will return the provided fallback image. If no fallback image is provided then an error image is generated.

The error correction level is a [[QR code feature|http://www.qrcode.com/en/about/error_correction.html]]:

<<<
QR Code has error correction capability to restore data if the code is dirty or damaged. ... Level Q or H may be selected for factory environment where QR Code get dirty, whereas Level L may be selected for clean environment with the large amount of data. Typically, Level M (15%) is most frequently selected.
<<<

!! Examples

Making a QR code for a simple string of text:

```
<<makeqr "Hello there!">>
```

Making a QR code for the URL field of the current tiddler:

```
<$macrocall $name="makeqr" text={{!!url}}/>
```

Making a QR code for the URL of the current wiki:

```
<$macrocall $name="makeqr" text={{$:/info/url/full}}/>
```