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118 lines
4.4 KiB
118 lines
4.4 KiB
/*
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* QR Code generator demo (JavaScript)
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*
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* Copyright (c) 2016 Project Nayuki
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* https://www.nayuki.io/page/qr-code-generator-library
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*
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* (MIT License)
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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* - The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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* - The Software is provided "as is", without warranty of any kind, express or
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* implied, including but not limited to the warranties of merchantability,
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* fitness for a particular purpose and noninfringement. In no event shall the
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* authors or copyright holders be liable for any claim, damages or other
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* liability, whether in an action of contract, tort or otherwise, arising from,
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* out of or in connection with the Software or the use or other dealings in the
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* Software.
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*/
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"use strict";
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function redrawQrCode() {
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// Returns a QrCode.Ecc object based on the radio buttons in the HTML form.
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function getInputErrorCorrectionLevel() {
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if (document.getElementById("errcorlvl-medium").checked)
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return qrcodegen.QrCode.Ecc.MEDIUM;
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else if (document.getElementById("errcorlvl-quartile").checked)
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return qrcodegen.QrCode.Ecc.QUARTILE;
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else if (document.getElementById("errcorlvl-high").checked)
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return qrcodegen.QrCode.Ecc.HIGH;
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else // In case no radio button is depressed
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return qrcodegen.QrCode.Ecc.LOW;
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}
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// Get form inputs and compute QR Code
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var ecl = getInputErrorCorrectionLevel();
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var text = document.getElementById("text-input").value;
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var segs = qrcodegen.QrSegment.makeSegments(text);
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var qr = qrcodegen.encodeSegments(segs, ecl);
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// Get scale and border
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var scale = parseInt(document.getElementById("scale-input").value, 10);
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var border = parseInt(document.getElementById("border-input").value, 10);
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if (scale <= 0 || border < 0 || scale > 30 || border > 100)
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return;
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// Draw QR Code onto canvas
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var canvas = document.getElementById("qrcode-canvas");
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var width = (qr.getSize() + border * 2) * scale;
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if (canvas.width != width) {
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canvas.width = width;
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canvas.height = width;
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}
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var ctx = canvas.getContext("2d");
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for (var y = -border; y < qr.getSize() + border; y++) {
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for (var x = -border; x < qr.getSize() + border; x++) {
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ctx.fillStyle = qr.getModule(x, y) == 1 ? "#000000" : "#FFFFFF";
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ctx.fillRect((x + border) * scale, (y + border) * scale, scale, scale);
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}
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}
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// Returns a string to describe the given list of segments.
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function describeSegments(segs) {
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if (segs.length == 0)
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return "none";
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else if (segs.length == 1) {
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var mode = segs[0].getMode();
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var Mode = qrcodegen.QrSegment.Mode;
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if (mode == Mode.NUMERIC ) return "numeric";
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if (mode == Mode.ALPHANUMERIC) return "alphanumeric";
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if (mode == Mode.BYTE ) return "byte";
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if (mode == Mode.KANJI ) return "kanji";
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return "unknown";
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} else
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return "multiple";
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}
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// Returns the number of Unicode code points in the given UTF-16 string.
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function countUnicodeChars(str) {
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var result = 0;
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for (var i = 0; i < str.length; i++, result++) {
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var c = str.charCodeAt(i);
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if (c < 0xD800 || c >= 0xE000)
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continue;
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else if (0xD800 <= c && c < 0xDC00) { // High surrogate
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i++;
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var d = str.charCodeAt(i);
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if (0xDC00 <= d && d < 0xE000) // Low surrogate
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continue;
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}
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throw "Invalid UTF-16 string";
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}
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return result;
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}
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// Show the QR Code symbol's statistics as a string
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var stats = "QR Code version = " + qr.getVersion() + ", ";
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stats += "mask pattern = " + qr.getMask() + ", ";
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stats += "character count = " + countUnicodeChars(text) + ",\n";
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stats += "encoding mode = " + describeSegments(segs) + ", ";
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stats += "error correction = level " + "LMQH".charAt(qr.getErrorCorrectionLevel().ordinal) + ", ";
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stats += "data bits = " + qrcodegen.QrSegment.getTotalBits(segs, qr.getVersion()) + ".";
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var elem = document.getElementById("statistics-output");
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while (elem.firstChild != null)
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elem.removeChild(elem.firstChild);
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elem.appendChild(document.createTextNode(stats));
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}
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redrawQrCode();
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