javaScript生成二维码（改造jquery.qrcode.js，使之支持中文，能带logo）

Posted 2020-08-26

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最近公司要求使用javascript生成二维码，在网上搜了很多相关的资料，都不是很全面，俗话说：自己动手，丰衣足食。

（这里吐槽下，有网友有了解决方案，却刻意把源代码压缩了，导致不知道改了什么东西，知识大家一起学习嘛，授人与鱼不如授人与渔！）

总结如下：

资料搜索

技术分享

选择star最多的两个

技术分享

第一个就是用的比较多的jquery.qrcode.js（但不支持中文，不能带logo）啦，第二个支持ie6+，支持中文，根据第二个源代码，使得，jquery.qrcode.js，支持中文。

支持中文

 1 //qrcode.js
 2 function QR8bitByte(data) {
 3     this.mode = QRMode.MODE_8BIT_BYTE;
 4     this.data = data;
 5 }
 6 
 7 QR8bitByte.prototype = {
 8 
 9     getLength : function(buffer) {
10         return this.data.length;
11     },
12 
13     write : function(buffer) {
14         for (var i = 0; i < this.data.length; i++) {
15             // not JIS ...
16             buffer.put(this.data.charCodeAt(i), 8);
17         }
18     }
19 };

修改如下（就是复制粘贴了第二份代码的头部）：

function QR8bitByte(data) {
    this.mode = QRMode.MODE_8BIT_BYTE;
    this.data = data;
    this.parsedData = [];

    // Added to support UTF-8 Characters
    for (var i = 0, l = this.data.length; i < l; i++) {
        var byteArray = [];
        var code = this.data.charCodeAt(i);

        if (code > 0x10000) {
            byteArray[0] = 0xF0 | ((code & 0x1C0000) >>> 18);
            byteArray[1] = 0x80 | ((code & 0x3F000) >>> 12);
            byteArray[2] = 0x80 | ((code & 0xFC0) >>> 6);
            byteArray[3] = 0x80 | (code & 0x3F);
        } else if (code > 0x800) {
            byteArray[0] = 0xE0 | ((code & 0xF000) >>> 12);
            byteArray[1] = 0x80 | ((code & 0xFC0) >>> 6);
            byteArray[2] = 0x80 | (code & 0x3F);
        } else if (code > 0x80) {
            byteArray[0] = 0xC0 | ((code & 0x7C0) >>> 6);
            byteArray[1] = 0x80 | (code & 0x3F);
        } else {
            byteArray[0] = code;
        }

        this.parsedData.push(byteArray);
    }

    this.parsedData = Array.prototype.concat.apply([], this.parsedData);

    if (this.parsedData.length != this.data.length) {
        this.parsedData.unshift(191);
        this.parsedData.unshift(187);
        this.parsedData.unshift(239);
    }
}

QR8bitByte.prototype = {
    getLength: function (buffer) {
        return this.parsedData.length;
    },
    write: function (buffer) {
        for (var i = 0, l = this.parsedData.length; i < l; i++) {
            buffer.put(this.parsedData[i], 8);
        }
    }
};

网上也提供的解决方案：

//在传入文本处转码也可
function utf16to8(str) {
    var out, i, len, c;
    out = "";
    len = str.length;
    for(i = 0; i < len; i++) {
        c = str.charCodeAt(i);
        if ((c >= 0x0001) && (c <= 0x007F)) {
            out += str.charAt(i);
        } else if (c > 0x07FF) {
            out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
            out += String.fromCharCode(0x80 | ((c >>  6) & 0x3F));
            out += String.fromCharCode(0x80 | ((c >>  0) & 0x3F));
        } else {
            out += String.fromCharCode(0xC0 | ((c >>  6) & 0x1F));
            out += String.fromCharCode(0x80 | ((c >>  0) & 0x3F));
        }
    }
    return out;
}

支持自定义logo

修改jquery.qrcode.js，createCanvas函数

var createCanvas    = function(){
            // create the qrcode itself
            var qrcode  = new QRCode(options.typeNumber, options.correctLevel);
            qrcode.addData(options.text);
            qrcode.make();

            // create canvas element
            var canvas  = document.createElement(‘canvas‘);
            canvas.width    = options.width;
            canvas.height   = options.height;
            var ctx     = canvas.getContext(‘2d‘);

            //增加以下代码，把图片画出来
            if( options.src ) {//传进来的图片地址
                //图片大小
                options.imgWidth = options.imgWidth || options.width / 4.7;
                options.imgHeight = options.imgHeight || options.height / 4.7;
                var img = new Image();
                img.src = options.src;
                //不放在onload里，图片出不来
                img.onload = function () {
                    ctx.drawImage(img, (options.width - options.imgWidth) / 2, (options.height - options.imgHeight) / 2, options.imgWidth, options.imgHeight);
                }
            }
            // compute tileW/tileH based on options.width/options.height
            var tileW   = options.width  / qrcode.getModuleCount();
            var tileH   = options.height / qrcode.getModuleCount();

            // draw in the canvas
            for( var row = 0; row < qrcode.getModuleCount(); row++ ){
                for( var col = 0; col < qrcode.getModuleCount(); col++ ){
                    ctx.fillStyle = qrcode.isDark(row, col) ? options.foreground : options.background;
                    var w = (Math.ceil((col+1)*tileW) - Math.floor(col*tileW));
                    var h = (Math.ceil((row+1)*tileW) - Math.floor(row*tileW));
                    ctx.fillRect(Math.round(col*tileW),Math.round(row*tileH), w, h);  
                }   
            }
            // return just built canvas
            return canvas;
        };

修改jquery.qrcode.js，createTable函数（不支持canvas用table画二维码）

var createTable = function(){
            // create the qrcode itself
            var qrcode  = new QRCode(options.typeNumber, options.correctLevel);
            qrcode.addData(options.text);
            qrcode.make();

            // create table element
            var $table    = $(‘<table></table>‘)
                .css("width", options.width+"px")
                .css("height", options.height+"px")
                .css("border", "0px")
                .css("border-collapse", "collapse")
                .css(‘background-color‘, options.background);

            // compute tileS percentage
            var tileW   = options.width / qrcode.getModuleCount();
            var tileH   = options.height / qrcode.getModuleCount();

            // draw in the table
            for(var row = 0; row < qrcode.getModuleCount(); row++ ){
                var $row = $(‘<tr></tr>‘).css(‘height‘, tileH+"px").appendTo($table);

                for(var col = 0; col < qrcode.getModuleCount(); col++ ){
                    $(‘<td></td>‘)
                        .css(‘width‘, tileW+"px")
                        .css(‘background-color‘, qrcode.isDark(row, col) ? options.foreground : options.background)
                        .appendTo($row);
                }   
            }

            //主要思想，把table，和img标签放在同一个div下，div relative定位，然后使得图片absolute定位在table中间
            if( options.src ) {
                options.imgWidth = options.imgWidth || options.width / 4.7;
                options.imgHeight = options.imgHeight || options.height / 4.7;
                var $img = $(‘<img>‘).attr("src", options.src)
                    .css("width", options.imgWidth)
                    .css("height", options.imgHeight)
                    .css("position", "absolute")
                    .css("left", (options.width - options.imgWidth) / 2)
                    .css("top", (options.height - options.imgHeight) / 2);
                $table = $(‘<div style="position:relative;"></div>‘)
                    .append($table)
                    .append($img);
            }

            // return just built canvas
            return $table;
        };

对IE做特殊判断，大家懂的

//判断是否IE, IE8以下，用 table，否则用 canvas
        var isIE = function() {
            var b = document.createElement(‘b‘);
            b.innerhtml = ‘<!--[if IE]><i></i><![endif]-->‘;
            return b.getElementsByTagName(‘i‘).length === 1;
        };
        options.render = options.render ||
            (isIE(6) || isIE(7) || isIE(8))? "table": "canvas";

改过后的jquery.qrcode.js如下：

(function( $ ){
    $.fn.qrcode = function(options) {
        // if options is string, 
        if( typeof options === ‘string‘ ){
            options = { text: options };
        }

        //判断是否IE, IE8以下，用 table，否则用 canvas
        var isIE = function() {
            var b = document.createElement(‘b‘);
            b.innerHTML = ‘<!--[if IE]><i></i><![endif]-->‘;
            return b.getElementsByTagName(‘i‘).length === 1;
        };
        options.render = options.render ||
            (isIE(6) || isIE(7) || isIE(8))? "table": "canvas";
        // set default values
        // typeNumber < 1 for automatic calculation
        options = $.extend( {}, {
            // render       : "canvas",
            width       : 256,
            height      : 256,
            typeNumber  : -1,
            correctLevel    : QRErrorCorrectLevel.H,
                        background      : "#ffffff",
                        foreground      : "#000000"
        }, options);

        var createCanvas    = function(){
            // create the qrcode itself
            var qrcode  = new QRCode(options.typeNumber, options.correctLevel);
            qrcode.addData(options.text);
            qrcode.make();

            // create canvas element
            var canvas  = document.createElement(‘canvas‘);
            canvas.width    = options.width;
            canvas.height   = options.height;
            var ctx     = canvas.getContext(‘2d‘);

            //在中间画logo
            if( options.src ) {
                options.imgWidth = options.imgWidth || options.width / 4.7;
                options.imgHeight = options.imgHeight || options.height / 4.7;
                var img = new Image();
                img.src = options.src;
                img.onload = function () {
                    ctx.drawImage(img, (options.width - options.imgWidth) / 2, (options.height - options.imgHeight) / 2, options.imgWidth, options.imgHeight);
                }
            }
            // compute tileW/tileH based on options.width/options.height
            var tileW   = options.width  / qrcode.getModuleCount();
            var tileH   = options.height / qrcode.getModuleCount();

            // draw in the canvas
            for( var row = 0; row < qrcode.getModuleCount(); row++ ){
                for( var col = 0; col < qrcode.getModuleCount(); col++ ){
                    ctx.fillStyle = qrcode.isDark(row, col) ? options.foreground : options.background;
                    var w = (Math.ceil((col+1)*tileW) - Math.floor(col*tileW));
                    var h = (Math.ceil((row+1)*tileW) - Math.floor(row*tileW));
                    ctx.fillRect(Math.round(col*tileW),Math.round(row*tileH), w, h);  
                }   
            }
            // return just built canvas
            return canvas;
        };

        // from Jon-Carlos Rivera (https://github.com/imbcmdth)
        var createTable = function(){
            // create the qrcode itself
            var qrcode  = new QRCode(options.typeNumber, options.correctLevel);
            qrcode.addData(options.text);
            qrcode.make();

            // create table element
            var $table    = $(‘<table></table>‘)
                .css("width", options.width+"px")
                .css("height", options.height+"px")
                .css("border", "0px")
                .css("border-collapse", "collapse")
                .css(‘background-color‘, options.background);

            // compute tileS percentage
            var tileW   = options.width / qrcode.getModuleCount();
            var tileH   = options.height / qrcode.getModuleCount();

            // draw in the table
            for(var row = 0; row < qrcode.getModuleCount(); row++ ){
                var $row = $(‘<tr></tr>‘).css(‘height‘, tileH+"px").appendTo($table);

                for(var col = 0; col < qrcode.getModuleCount(); col++ ){
                    $(‘<td></td>‘)
                        .css(‘width‘, tileW+"px")
                        .css(‘background-color‘, qrcode.isDark(row, col) ? options.foreground : options.background)
                        .appendTo($row);
                }   
            }

            //生成logo
            if( options.src ) {
                options.imgWidth = options.imgWidth || options.width / 4.7;
                options.imgHeight = options.imgHeight || options.height / 4.7;
                var $img = $(‘<img>‘).attr("src", options.src)
                    .css("width", options.imgWidth)
                    .css("height", options.imgHeight)
                    .css("position", "absolute")
                    .css("left", (options.width - options.imgWidth) / 2)
                    .css("top", (options.height - options.imgHeight) / 2);
                $table = $(‘<div style="position:relative;"></div>‘)
                    .append($table)
                    .append($img);
            }

            // return just built canvas
            return $table;
        };


        return this.each(function(){
            var element = options.render == "canvas" ? createCanvas() : createTable();
            $(element).appendTo(this);
        });
    };
})( jQuery );

测试

jQuery(‘#qrcodeTable‘).qrcode({
        render  : "table",
        text    : "中文://jetienne.com",
        src: ‘./logo32.png‘
    });
    jQuery(‘#qrcodeCanvas‘).qrcode({
        text    : "中午你://jetienne.com",
        src: ‘./logo32.png‘
    });

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