65 lines
2.1 KiB
JavaScript
65 lines
2.1 KiB
JavaScript
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//---------------------------------------------------------------------
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// JavaScript-HTML5 QRCode Generator
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//
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// Copyright (c) 2011 Amanuel Tewolde
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//
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// Licensed under the MIT license:
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// http://www.opensource.org/licenses/mit-license.php
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//
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//---------------------------------------------------------------------
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// Generates a QRCode of text provided.
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// First QRCode is rendered to a canvas.
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// The canvas is then turned to an image PNG
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// before being returned as an <img> tag.
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function showQRCode(text) {
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var dotsize = 5; // size of box drawn on canvas
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var padding = 10; // (white area around your QRCode)
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var black = "rgb(0,0,0)";
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var white = "rgb(255,255,255)";
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var QRCodeVersion = 15; // 1-40 see http://www.denso-wave.com/qrcode/qrgene2-e.html
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var canvas=document.createElement('canvas');
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var qrCanvasContext = canvas.getContext('2d');
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try {
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// QR Code Error Correction Capability
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// Higher levels improves error correction capability while decreasing the amount of data QR Code size.
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// QRErrorCorrectLevel.L (5%) QRErrorCorrectLevel.M (15%) QRErrorCorrectLevel.Q (25%) QRErrorCorrectLevel.H (30%)
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// eg. L can survive approx 5% damage...etc.
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var qr = new QRCode(QRCodeVersion, QRErrorCorrectLevel.L);
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qr.addData(text);
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qr.make();
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}
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catch(err) {
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var errorChild = document.createElement("p");
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var errorMSG = document.createTextNode("QR Code FAIL! " + err);
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errorChild.appendChild(errorMSG);
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return errorChild;
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}
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var qrsize = qr.getModuleCount();
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canvas.setAttribute('height',(qrsize * dotsize) + padding);
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canvas.setAttribute('width',(qrsize * dotsize) + padding);
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var shiftForPadding = padding/2;
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if (canvas.getContext){
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for (var r = 0; r < qrsize; r++) {
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for (var c = 0; c < qrsize; c++) {
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if (qr.isDark(r, c))
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qrCanvasContext.fillStyle = black;
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else
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qrCanvasContext.fillStyle = white;
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qrCanvasContext.fillRect ((c*dotsize) +shiftForPadding,(r*dotsize) + shiftForPadding,dotsize,dotsize); // x, y, w, h
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}
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}
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}
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var imgElement = document.createElement("img");
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imgElement.src = canvas.toDataURL("image/png");
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return imgElement;
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}
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