TiddlyWiki5/plugins/tiddlywiki/qrcode/makeqr.js

75 wiersze
1.8 KiB
JavaScript

/*\
title: $:/plugins/tiddlywiki/qrcode/makeqr.js
type: application/javascript
module-type: macro
Macro to convert a string into a QR Code
\*/
(function(){
/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";
/*
Information about this macro
*/
var qrcode = require("$:/plugins/tiddlywiki/qrcode/qrcode.js");
var QRCODE_GENERATION_ERROR_PREFIX = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 300 300"><text x="0" y="30" fill="red" font-family="Helvetica, sans-serif" font-size="18">',
QRCODE_GENERATION_ERROR_SUFFIX = '</text></svg>';
exports.name = "makeqr";
exports.params = [
{name: "text"},
{name: "size"},
{name: "errorCorrectLevel"},
{name: "fallback"}
];
/*
Run the macro
*/
exports.run = function(text,size,errorCorrectLevel,fallback) {
var result;
try {
result = generateQrCode(text,{size: size, errorCorrectLevel: errorCorrectLevel});
} catch (ex) {
console.log("makeqr error: " + ex);
result = fallback || ("data:image/svg+xml," + encodeURI(QRCODE_GENERATION_ERROR_PREFIX + ex + QRCODE_GENERATION_ERROR_SUFFIX));
}
return result || "";
};
function generateQrCode(text,options) {
options = options || {};
var typeNumber = options.typeNumber || 4,
errorCorrectLevel = options.errorCorrectLevel || "M",
size = options.size || 500,
qr;
try {
qr = qrcode(typeNumber,errorCorrectLevel);
qr.addData(text);
qr.make();
} catch (e) {
if(typeNumber >= 40) {
throw new Error("Text too long to encode");
} else {
return generateQrCode(text, {
size: size,
errorCorrectLevel: errorCorrectLevel,
typeNumber: typeNumber + 1
});
}
}
var cellsize = parseInt(size / qr.getModuleCount()),
margin = parseInt((size - qr.getModuleCount() * cellsize) / 2);
return qr.createImgTag(cellsize, margin, size);
}
})();