JavaScript 生成二维码（修改qrcode.js添加icon支持）
JS生成二维码，我用到的是 qrcode.js 这个插件，地址如下：
https://github.com/davidshimjs/qrcodejs
测试 DEMO 如下（我有对源码进行修改才支持图片的）：
https://github.com/555chy/qrcodejs
在线演示地址
https://555chy.github.io/qrcodejs/demo.html
由于CSDN显示的代码中，所有onload会被吃掉，请自行添加。或到我的Github上下载qrcode.js和demo.html查看演示DEMO
注意到：qrcode.js 这个插件目前是不支持嵌入图片的，因此是要对源码进行相应的修改。
这是我对源码做的修改并 “Pull request” 给原作者了：https://github.com/davidshimjs/qrcodejs/pull/181/files
要想修改别人的源码首先要了解其大致的流程，注意以下关键字段
var useSVG = document.documentElement.tagName.toLowerCase() === "svg";
// Drawing in DOM by using Table tag
var Drawing = useSVG ? svgDrawer : !_isSupportCanvas() ? (function () { ... }
这段代码说的是先判断是否支持SVG，如果支持则使用SVG；否则判断是否支持Canvas，如果支持则使用Canvas，如果不支持，就使用Table来构造点阵。
我这里仅修改使用 Canvas 的这种方式。在修改前，我们首先要了解一下，如何绘制圆角矩形（canvas默认只有绘制矩形的方法，并不支持绘制圆角），我们可以通过1/4的圆来模拟圆角。
function drawRoundRect(ctx, x, y, width, height, radius, lineWidth, lineColor) {
ctx.lineWidth = lineWidth;
ctx.strokeStyle = lineColor
ctx.beginPath();
ctx.arc(x + radius, y + radius, radius, Math.PI, Math.PI * 3 / 2);
ctx.lineTo(width - radius + x, y);
ctx.arc(width - radius + x, radius + y, radius, Math.PI * 3 / 2, Math.PI * 2);
ctx.lineTo(width + x, height + y - radius);
ctx.arc(width - radius + x, height - radius + y, radius, 0, Math.PI * 1 / 2);
ctx.lineTo(radius + x, height +y);
ctx.arc(radius + x, height - radius + y, radius, Math.PI * 1 / 2, Math.PI);
ctx.closePath();
ctx.stroke();
};
绘制完圆角矩形，接下来我们就可以开始添加ICON了。
首先用clip方法剪出刚刚画的矩形的范围（clip的意思是只能在上面的区域内绘制才是有效的）
然后开始绘制图标，由于这里提供的是图标的SRC，因此我们需要等待它load完毕，才能拿到这个图形
这里我使用了ES6新推出的语法 async/await 配合上 promise，可以将异步的方式转为同步的，进而减小对原代码的改动
注意：函数中若包含有await语句，则该函数必须声明为async。且在调用该async函数时，如果想将该函数变为同步的，也需要在调用语句前加await。
async/await的出现有效的避免了Promise的回调地狱
Drawing.prototype.addIcon = async function (iconSrc) {
//通过ES6的async/await语法将异步的Promise转为同步方法
const image = await new Promise((resolve, reject) => {
const image = new Image();
image.src = iconSrc;
image.()=>{resolve(image);};
});
//图片占整个二维码的比例，在QRCode.CorrectLevel.L测试可行，那么更高的纠错率就更没问题了
const ratio = 0.3;
const radius = 10;
const marginRatio = (1-ratio)/2;
const x = this._htOption.width * marginRatio;
const y = this._htOption.height * marginRatio;
const width = this._htOption.width * ratio;
const height = this._htOption.height * ratio;
drawRoundRect(this._oContext, x, y, width, height, this._htOption.iconRadius, this._htOption.iconBorderWidth, this._htOption.iconBorderColor);
this._oContext.clip();
this._oContext.drawImage(image, x, y, width, height);
this._oContext.restore();
};
新增安卓手机兼容性的问题，比如版本号，有些返回的是9.0，有些是9，低版本基本不存在了，所以这块判断可以直接略去
// android 2.x doesn't support Data-URI spec
function _getAndroid() {
/*
var android = false;
var sAgent = navigator.userAgent;
if (/android/i.test(sAgent)) { // android
android = true;
var aMat = sAgent.toString().match(/android ([0-9]\.[0-9])/i);
if (aMat && aMat[1]) {
android = parseFloat(aMat[1]);
}
}
return android;
由于android 2.x的旧机子已经根本不用考虑了，
而这个方法在makeImage的时候被调用，并不是用来判断是否是android机子，
只是用来判断是需要考虑android老设备不支持Data-URI的问题，所以这里直接置false，不考虑即可
*/
return false;
}
由于只有二维码，要是下载下来比较难看，因此就添加了个边框
首先要添加配置项
/**
* @class QRCode
* @constructor
* @example
* new QRCode(document.getElementById("test"), "http://jindo.dev.naver.com/collie");
*
* @example
* var oQRCode = new QRCode("test", {
* text : "http://naver.com",
* width : 128,
* height : 128
* });
*
* oQRCode.clear(); // Clear the QRCode.
* oQRCode.makeCode("http://map.naver.com"); // Re-create the QRCode.
*
* @param {HTMLElement|String} el target element or 'id' attribute of element.
* @param {Object|String} vOption
* @param {String} vOption.text QRCode link data
* @param {Number} [vOption.width=256]
* @param {Number} [vOption.height=256]
* @param {String} [vOption.colorDark="#000000"]
* @param {String} [vOption.colorLight="#ffffff"]
* @param {QRCode.CorrectLevel} [vOption.correctLevel=QRCode.CorrectLevel.H] [L|M|Q|H]
*/
QRCode = function (el, vOption) {
this._htOption = {
//二维码大小
width : 256,
height : 256,
typeNumber : 4,
colorDark : "#000000",
colorLight : "#ffffff",
correctLevel : QRErrorCorrectLevel.H,
//二维码中间图标
iconSrc: undefined,
iconBorderWidth: 0,
iconBorderColor: "black",
//边框图片
borderImg: undefined,
//整个画布大小，边框充满整个画布
borderImgWidth: undefined,
borderImgHeight: undefined,
//二维码相对画布或边框图片的偏移
qrcodeOffsetX: undefined,
qrcodeOffsetY: undefined,
};
然后添加绘制边框的函数
Drawing.prototype.addBorder = async function (borderSrc) {
const image = await new Promise((resolve, reject) => {
const image = new Image();
image.src = borderSrc;
image.()=>{resolve(image);};
});
this._oContext.drawImage(image, 0, 0, this._htOption.borderImgWidth, this._htOption.borderImgHeight);
}
最后修改调用处，让边框图像最后绘制，使它的边框盖在二维码上面
/**
* Make the QRCode
*
* @param {String} sText link data
*/
QRCode.prototype.makeCode = async function (sText) {
this._oQRCode = new QRCodeModel(_getTypeNumber(sText, this._htOption.correctLevel), this._htOption.correctLevel);
this._oQRCode.addData(sText);
this._oQRCode.make();
this._el.title = sText;
const borderExists = typeof(this._htOption.qrcodeOffsetX) !== undefined && typeof(this._htOption.qrcodeOffsetY) !== undefined;
if(borderExists) {
const x = this._htOption.qrcodeOffsetX;
const y = this._htOption.qrcodeOffsetY;
this._oDrawing._oContext.save();
this._oDrawing._oContext.translate(x, y);
}
this._oDrawing.draw(this._oQRCode);
if(typeof(this._htOption.iconSrc) !== undefined) {
//这里是异步的函数，只有加了await才会变成同步（注意：即使函数里面有await，这个函数也是异步执行的）
await this._oDrawing.addIcon(this._htOption.iconSrc);
}
if(borderExists) {
this._oDrawing._oContext.restore();
}
if(typeof(this._htOption.borderImg) !== undefined) {
await this._oDrawing.addBorder(this._htOption.borderImg);
}
this.makeImage();
};
我这边图方便直接使用async/await同步执行。这样有个问题，就是两个图片下载的总时间是加法计算，优化的方案是改为Promise.all使得
它们并行执行这样的话所花的时间就是最长的那个。当然，一般来说放在手机上显示的图片要求不大于10KB，同步请求也是没问题的，用户基本感觉不到时间差异。
由于有的需求只是加个背景色
/**
* Make the QRCode
*
* @param {String} sText link data
*/
QRCode.prototype.makeCode = async function (sText) {
this._oQRCode = new QRCodeModel(_getTypeNumber(sText, this._htOption.correctLevel), this._htOption.correctLevel);
this._oQRCode.addData(sText);
this._oQRCode.make();
this._el.title = sText;
const offsetExists = typeof(this._htOption.qrcodeOffsetX) !== "undefined" && typeof(this._htOption.qrcodeOffsetY) !== "undefined";
const borderExists = typeof(this._htOption.borderWidth) !== "undefined" && typeof(this._htOption.borderHeight) !== "undefined";
const borderImgExists = typeof(this._htOption.borderImg) !== "undefined";
const borderBgColorExists = typeof this._htOption.borderBgColor !== "undefined" && borderExists;
if(borderBgColorExists) {
//如果不填充白色，下载下来的图片默认为透明色，很难看
this._oDrawing._oContext.fillStyle = this._htOption.borderBgColor ? this._htOption.borderBgColor : "white";
this._oDrawing._oContext.fillRect(0, 0, this._htOption.borderWidth, this._htOption.borderHeight);
this._oDrawing._oContext.save();
}
if(offsetExists) {
const x = this._htOption.qrcodeOffsetX;
const y = this._htOption.qrcodeOffsetY;
this._oDrawing._oContext.save();
this._oDrawing._oContext.translate(x, y);
}
if(borderBgColorExists) {
this._oDrawing._oContext.rect(0,0,this._htOption.width,this._htOption.height);
this._oDrawing._oContext.clip();
}
this._oDrawing.draw(this._oQRCode);
if(typeof(this._htOption.iconSrc) !== "undefined") {
//这里是异步的函数，只有加了await才会变成同步（注意：即使函数里面有await，这个函数也是异步执行的）
await this._oDrawing.addIcon(this._htOption.iconSrc);
}
if(borderBgColorExists) {
this._oDrawing._oContext.restore();
}
if(offsetExists) {
this._oDrawing._oContext.restore();
}
if(borderImgExists) {
await this._oDrawing.addBorder(this._htOption.borderImg);
}
this.makeImage();
};
最终修改后的完整代码如下：
/**
* @fileoverview
* - Using the 'QRCode for Javascript library'
* - Fixed dataset of 'QRCode for Javascript library' for support full-spec.
* - this library has no dependencies.
*
* @author davidshimjs
* @see http://www.d-project.com/
* @see http://jeromeetienne.github.com/jquery-qrcode/
*/
var QRCode;
(function () {
//---------------------------------------------------------------------
// QRCode for JavaScript
//
// Copyright (c) 2009 Kazuhiko Arase
//
// URL: http://www.d-project.com/
//
// Licensed under the MIT license:
// http://www.opensource.org/licenses/mit-license.php
//
// The word "QR Code" is registered trademark of
// DENSO WAVE INCORPORATED
// http://www.denso-wave.com/qrcode/faqpatent-e.html
//
//---------------------------------------------------------------------
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);
}
}
};
function QRCodeModel(typeNumber, errorCorrectLevel) {
this.typeNumber = typeNumber;
this.errorCorrectLevel = errorCorrectLevel;
this.modules = null;
this.moduleCount = 0;
this.dataCache = null;
this.dataList = [];
}
QRCodeModel.prototype={addData:function(data){var newData=new QR8bitByte(data);this.dataList.push(newData);this.dataCache=null;},isDark:function(row,col){if(row<0||this.moduleCount<=row||col<0||this.moduleCount<=col){throw new Error(row+","+col);}
return this.modules[row][col];},getModuleCount:function(){return this.moduleCount;},make:function(){this.makeImpl(false,this.getBestMaskPattern());},makeImpl:function(test,maskPattern){this.moduleCount=this.typeNumber*4+17;this.modules=new Array(this.moduleCount);for(var row=0;row=7){this.setupTypeNumber(test);}
if(this.dataCache==null){this.dataCache=QRCodeModel.createData(this.typeNumber,this.errorCorrectLevel,this.dataList);}
this.mapData(this.dataCache,maskPattern);},setupPositionProbePattern:function(row,col){for(var r=-1;r<=7;r++){if(row+r<=-1||this.moduleCount<=row+r)continue;for(var c=-1;c<=7;c++){if(col+c<=-1||this.moduleCount<=col+c)continue;if((0<=r&&r<=6&&(c==0||c==6))||(0<=c&&c<=6&&(r==0||r==6))||(2<=r&&r<=4&&2<=c&&c<=4)){this.modules[row+r][col+c]=true;}else{this.modules[row+r][col+c]=false;}}}},getBestMaskPattern:function(){var minLostPoint=0;var pattern=0;for(var i=0;i<8;i++){this.makeImpl(true,i);var lostPoint=QRUtil.getLostPoint(this);if(i==0||minLostPoint>lostPoint){minLostPoint=lostPoint;pattern=i;}}
return pattern;},createMovieClip:function(target_mc,instance_name,depth){var qr_mc=target_mc.createEmptyMovieClip(instance_name,depth);var cs=1;this.make();for(var row=0;row>i)&1)==1);this.modules[Math.floor(i/3)][i%3+this.moduleCount-8-3]=mod;}
for(var i=0;i<18;i++){var mod=(!test&&((bits>>i)&1)==1);this.modules[i%3+this.moduleCount-8-3][Math.floor(i/3)]=mod;}},setupTypeInfo:function(test,maskPattern){var data=(this.errorCorrectLevel<<3)|maskPattern;var bits=QRUtil.getBCHTypeInfo(data);for(var i=0;i<15;i++){var mod=(!test&&((bits>>i)&1)==1);if(i<6){this.modules[i][8]=mod;}else if(i<8){this.modules[i+1][8]=mod;}else{this.modules[this.moduleCount-15+i][8]=mod;}}
for(var i=0;i<15;i++){var mod=(!test&&((bits>>i)&1)==1);if(i<8){this.modules[8][this.moduleCount-i-1]=mod;}else if(i<9){this.modules[8][15-i-1+1]=mod;}else{this.modules[8][15-i-1]=mod;}}
this.modules[this.moduleCount-8][8]=(!test);},mapData:function(data,maskPattern){var inc=-1;var row=this.moduleCount-1;var bitIndex=7;var byteIndex=0;for(var col=this.moduleCount-1;col>0;col-=2){if(col==6)col--;while(true){for(var c=0;c<2;c++){if(this.modules[row][col-c]==null){var dark=false;if(byteIndex>>bitIndex)&1)==1);}
var mask=QRUtil.getMask(maskPattern,row,col-c);if(mask){dark=!dark;}
this.modules[row][col-c]=dark;bitIndex--;if(bitIndex==-1){byteIndex++;bitIndex=7;}}}
row+=inc;if(row<0||this.moduleCount<=row){row-=inc;inc=-inc;break;}}}}};QRCodeModel.PAD0=0xEC;QRCodeModel.PAD1=0x11;QRCodeModel.createData=function(typeNumber,errorCorrectLevel,dataList){var rsBlocks=QRRSBlock.getRSBlocks(typeNumber,errorCorrectLevel);var buffer=new QRBitBuffer();for(var i=0;itotalDataCount*8){throw new Error("code length overflow. ("
+buffer.getLengthInBits()
+">"
+totalDataCount*8
+")");}
if(buffer.getLengthInBits()+4<=totalDataCount*8){buffer.put(0,4);}
while(buffer.getLengthInBits()%8!=0){buffer.putBit(false);}
while(true){if(buffer.getLengthInBits()>=totalDataCount*8){break;}
buffer.put(QRCodeModel.PAD0,8);if(buffer.getLengthInBits()>=totalDataCount*8){break;}
buffer.put(QRCodeModel.PAD1,8);}
return QRCodeModel.createBytes(buffer,rsBlocks);};QRCodeModel.createBytes=function(buffer,rsBlocks){var offset=0;var maxDcCount=0;var maxEcCount=0;var dcdata=new Array(rsBlocks.length);var ecdata=new Array(rsBlocks.length);for(var r=0;r=0)?modPoly.get(modIndex):0;}}
var totalCodeCount=0;for(var i=0;i=0){d^=(QRUtil.G15<<(QRUtil.getBCHDigit(d)-QRUtil.getBCHDigit(QRUtil.G15)));}
return((data<<10)|d)^QRUtil.G15_MASK;},getBCHTypeNumber:function(data){var d=data<<12;while(QRUtil.getBCHDigit(d)-QRUtil.getBCHDigit(QRUtil.G18)>=0){d^=(QRUtil.G18<<(QRUtil.getBCHDigit(d)-QRUtil.getBCHDigit(QRUtil.G18)));}
return(data<<12)|d;},getBCHDigit:function(data){var digit=0;while(data!=0){digit++;data>>>=1;}
return digit;},getPatternPosition:function(typeNumber){return QRUtil.PATTERN_POSITION_TABLE[typeNumber-1];},getMask:function(maskPattern,i,j){switch(maskPattern){case QRMaskPattern.PATTERN000:return(i+j)%2==0;case QRMaskPattern.PATTERN001:return i%2==0;case QRMaskPattern.PATTERN010:return j%3==0;case QRMaskPattern.PATTERN011:return(i+j)%3==0;case QRMaskPattern.PATTERN100:return(Math.floor(i/2)+Math.floor(j/3))%2==0;case QRMaskPattern.PATTERN101:return(i*j)%2+(i*j)%3==0;case QRMaskPattern.PATTERN110:return((i*j)%2+(i*j)%3)%2==0;case QRMaskPattern.PATTERN111:return((i*j)%3+(i+j)%2)%2==0;default:throw new Error("bad maskPattern:"+maskPattern);}},getErrorCorrectPolynomial:function(errorCorrectLength){var a=new QRPolynomial([1],0);for(var i=0;i5){lostPoint+=(3+sameCount-5);}}}
for(var row=0;row=256){n-=255;}
return QRMath.EXP_TABLE[n];},EXP_TABLE:new Array(256),LOG_TABLE:new Array(256)};for(var i=0;i<8;i++){QRMath.EXP_TABLE[i]=1<>>(7-index%8))&1)==1;},put:function(num,length){for(var i=0;i>>(length-i-1))&1)==1);}},getLengthInBits:function(){return this.length;},putBit:function(bit){var bufIndex=Math.floor(this.length/8);if(this.buffer.length<=bufIndex){this.buffer.push(0);}
if(bit){this.buffer[bufIndex]|=(0x80>>>(this.length%8));}
this.length++;}};var QRCodeLimitLength=[[17,14,11,7],[32,26,20,14],[53,42,32,24],[78,62,46,34],[106,84,60,44],[134,106,74,58],[154,122,86,64],[192,152,108,84],[230,180,130,98],[271,213,151,119],[321,251,177,137],[367,287,203,155],[425,331,241,177],[458,362,258,194],[520,412,292,220],[586,450,322,250],[644,504,364,280],[718,560,394,310],[792,624,442,338],[858,666,482,382],[929,711,509,403],[1003,779,565,439],[1091,857,611,461],[1171,911,661,511],[1273,997,715,535],[1367,1059,751,593],[1465,1125,805,625],[1528,1190,868,658],[1628,1264,908,698],[1732,1370,982,742],[1840,1452,1030,790],[1952,1538,1112,842],[2068,1628,1168,898],[2188,1722,1228,958],[2303,1809,1283,983],[2431,1911,1351,1051],[2563,1989,1423,1093],[2699,2099,1499,1139],[2809,2213,1579,1219],[2953,2331,1663,1273]];
function _isSupportCanvas() {
return typeof CanvasRenderingContext2D != "undefined";
}
// android 2.x doesn't support Data-URI spec
function _getAndroid() {
/*
var android = false;
var sAgent = navigator.userAgent;
if (/android/i.test(sAgent)) { // android
android = true;
var aMat = sAgent.toString().match(/android ([0-9]\.[0-9])/i);
if (aMat && aMat[1]) {
android = parseFloat(aMat[1]);
}
}
return android;
由于android 2.x的旧机子已经根本不用考虑了，
而这个方法在makeImage的时候被调用，并不是用来判断是否是android机子，
只是用来判断是需要考虑android老设备不支持Data-URI的问题，所以这里直接置false，不考虑即可
*/
return false;
}
var svgDrawer = (function() {
var Drawing = function (el, htOption) {
this._el = el;
this._htOption = htOption;
};
Drawing.prototype.draw = function (oQRCode) {
var _htOption = this._htOption;
var _el = this._el;
var nCount = oQRCode.getModuleCount();
var nWidth = Math.floor(_htOption.width / nCount);
var nHeight = Math.floor(_htOption.height / nCount);
this.clear();
function makeSVG(tag, attrs) {
var el = document.createElementNS('http://www.w3.org/2000/svg', tag);
for (var k in attrs)
if (attrs.hasOwnProperty(k)) el.setAttribute(k, attrs[k]);
return el;
}
var svg = makeSVG("svg" , {'viewBox': '0 0 ' + String(nCount) + " " + String(nCount), 'width': '100%', 'height': '100%', 'fill': _htOption.colorLight});
svg.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:xlink", "http://www.w3.org/1999/xlink");
_el.appendChild(svg);
svg.appendChild(makeSVG("rect", {"fill": _htOption.colorLight, "width": "100%", "height": "100%"}));
svg.appendChild(makeSVG("rect", {"fill": _htOption.colorDark, "width": "1", "height": "1", "id": "template"}));
for (var row = 0; row < nCount; row++) {
for (var col = 0; col < nCount; col++) {
if (oQRCode.isDark(row, col)) {
var child = makeSVG("use", {"x": String(col), "y": String(row)});
child.setAttributeNS("http://www.w3.org/1999/xlink", "href", "#template")
svg.appendChild(child);
}
}
}
};
Drawing.prototype.clear = function () {
while (this._el.hasChildNodes())
this._el.removeChild(this._el.lastChild);
};
return Drawing;
})();
var useSVG = document.documentElement.tagName.toLowerCase() === "svg";
// Drawing in DOM by using Table tag
var Drawing = useSVG ? svgDrawer : !_isSupportCanvas() ? (function () {
var Drawing = function (el, htOption) {
this._el = el;
this._htOption = htOption;
};
/**
* Draw the QRCode
*
* @param {QRCode} oQRCode
*/
Drawing.prototype.draw = function (oQRCode) {
var _htOption = this._htOption;
var _el = this._el;
var nCount = oQRCode.getModuleCount();
var nWidth = Math.floor(_htOption.width / nCount);
var nHeight = Math.floor(_htOption.height / nCount);
var aHTML = [''];
for (var row = 0; row < nCount; row++) {
aHTML.push('');
for (var col = 0; col < nCount; col++) {
aHTML.push(' ');
}
aHTML.push('
');
_el.innerHTML = aHTML.join('');
// Fix the margin values as real size.
var elTable = _el.childNodes[0];
var nLeftMarginTable = (_htOption.width - elTable.offsetWidth) / 2;
var nTopMarginTable = (_htOption.height - elTable.offsetHeight) / 2;
if (nLeftMarginTable > 0 && nTopMarginTable > 0) {
elTable.style.margin = nTopMarginTable + "px " + nLeftMarginTable + "px";
}
};
/**
* Clear the QRCode
*/
Drawing.prototype.clear = function () {
this._el.innerHTML = '';
};
return Drawing;
})() : (function () { // Drawing in Canvas
function _onMakeImage() {
this._elImage.src = this._elCanvas.toDataURL("image/png");
this._elImage.style.display = "block";
//如果没有中心icon的话，二维码display会被设为none
//this._elCanvas.style.display = "none";
}
// Android 2.1 bug workaround
// http://code.google.com/p/android/issues/detail?id=5141
if (this._android && this._android <= 2.1) {
var factor = 1 / window.devicePixelRatio;
var drawImage = CanvasRenderingContext2D.prototype.drawImage;
CanvasRenderingContext2D.prototype.drawImage = function (image, sx, sy, sw, sh, dx, dy, dw, dh) {
if (("nodeName" in image) && /img/i.test(image.nodeName)) {
for (var i = arguments.length - 1; i >= 1; i--) {
arguments[i] = arguments[i] * factor;
}
} else if (typeof dw == "undefined") {
arguments[1] *= factor;
arguments[2] *= factor;
arguments[3] *= factor;
arguments[4] *= factor;
}
drawImage.apply(this, arguments);
};
}
/**
* Check whether the user's browser supports Data URI or not
*
* @private
* @param {Function} fSuccess Occurs if it supports Data URI
* @param {Function} fFail Occurs if it doesn't support Data URI
*/
function _safeSetDataURI(fSuccess, fFail) {
var self = this;
self._fFail = fFail;
self._fSuccess = fSuccess;
// Check it just once
if (self._bSupportDataURI === null) {
var el = document.createElement("img");
var fOnError = function() {
self._bSupportDataURI = false;
if (self._fFail) {
self._fFail.call(self);
}
};
var fOnSuccess = function() {
self._bSupportDataURI = true;
if (self._fSuccess) {
self._fSuccess.call(self);
}
};
el.onabort = fOnError;
el.onerror = fOnError;
el.onload = fOnSuccess;
el.src = "data:image/gif;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=="; // the Image contains 1px data.
return;
} else if (self._bSupportDataURI === true && self._fSuccess) {
self._fSuccess.call(self);
} else if (self._bSupportDataURI === false && self._fFail) {
self._fFail.call(self);
}
};
/**
* Drawing QRCode by using canvas
*
* @constructor
* @param {HTMLElement} el
* @param {Object} htOption QRCode Options
*/
var Drawing = function (el, htOption) {
this._bIsPainted = false;
this._android = _getAndroid();
this._htOption = htOption;
this._elCanvas = document.createElement("canvas");
this._elCanvas.width = htOption.curtainWidth ? htOption.curtainWidth : htOption.width;
this._elCanvas.height = htOption.curtainHeight ? htOption.curtainHeight : htOption.height;
el.appendChild(this._elCanvas);
this._el = el;
this._oContext = this._elCanvas.getContext("2d");
this._bIsPainted = false;
this._elImage = document.createElement("img");
this._elImage.alt = "Scan me!";
this._elImage.style.display = "none";
//this._el.appendChild(this._elImage);
this._bSupportDataURI = null;
};
/**
* Draw the QRCode
*
* @param {QRCode} oQRCode
*/
Drawing.prototype.draw = function (oQRCode) {
//目前真正被调用的是该draw方法
var _elImage = this._elImage;
var _oContext = this._oContext;
var _htOption = this._htOption;
var nCount = oQRCode.getModuleCount();
var nWidth = _htOption.width / nCount;
var nHeight = _htOption.height / nCount;
var nRoundedWidth = Math.round(nWidth);
var nRoundedHeight = Math.round(nHeight);
_elImage.style.display = "none";
this.clear();
for (var row = 0; row < nCount; row++) {
for (var col = 0; col < nCount; col++) {
var bIsDark = oQRCode.isDark(row, col);
var nLeft = col * nWidth;
var nTop = row * nHeight;
_oContext.strokeStyle = bIsDark ? _htOption.colorDark : _htOption.colorLight;
_oContext.lineWidth = 1;
_oContext.fillStyle = bIsDark ? _htOption.colorDark : _htOption.colorLight;
_oContext.fillRect(nLeft, nTop, nWidth, nHeight);
// 안티 앨리어싱 방지 처리
_oContext.strokeRect(
Math.floor(nLeft) + 0.5,
Math.floor(nTop) + 0.5,
nRoundedWidth,
nRoundedHeight
);
_oContext.strokeRect(
Math.ceil(nLeft) - 0.5,
Math.ceil(nTop) - 0.5,
nRoundedWidth,
nRoundedHeight
);
}
}
this._bIsPainted = true;
};
function drawRoundRect(ctx, x, y, width, height, radius, lineWidth, lineColor) {
ctx.lineWidth = lineWidth;
ctx.strokeStyle = lineColor;
ctx.beginPath();
ctx.arc(x + radius, y + radius, radius, Math.PI, Math.PI * 3 / 2);
ctx.lineTo(width - radius + x, y);
ctx.arc(width - radius + x, radius + y, radius, Math.PI * 3 / 2, Math.PI * 2);
ctx.lineTo(width + x, height + y - radius);
ctx.arc(width - radius + x, height - radius + y, radius, 0, Math.PI * 1 / 2);
ctx.lineTo(radius + x, height +y);
ctx.arc(radius + x, height - radius + y, radius, Math.PI * 1 / 2, Math.PI);
ctx.closePath();
//因为有的时候图片不需要设置边框线
if(lineWidth > 0) ctx.stroke();
};
Drawing.prototype.addIcon = async function (iconSrc) {
//通过ES6的async/await语法将异步的Promise转为同步方法
const image = await new Promise((resolve, reject) => {
const image = new Image();
image.src = iconSrc;
image.()=>{resolve(image);};
});
//图片占整个二维码的比例，在QRCode.CorrectLevel.L测试可行，那么更高的纠错率就更没问题了
const ratio = 0.3;
const radius = 10;
const marginRatio = (1-ratio)/2;
const x = this._htOption.width * marginRatio;
const y = this._htOption.height * marginRatio;
const width = this._htOption.width * ratio;
const height = this._htOption.height * ratio;
drawRoundRect(this._oContext, x, y, width, height, this._htOption.iconRadius, this._htOption.iconBorderWidth, this._htOption.iconBorderColor);
this._oContext.save();
this._oContext.clip();
this._oContext.drawImage(image, x, y, width, height);
this._oContext.restore();
};
Drawing.prototype.addCurtain = async function (curtainSrc) {
const image = await new Promise((resolve, reject) => {
const image = new Image();
image.src = curtainSrc;
image.()=>{resolve(image);};
});
this._oContext.drawImage(image, 0, 0, this._htOption.curtainWidth, this._htOption.curtainHeight);
}
/**
* Make the image from Canvas if the browser supports Data URI.
*/
Drawing.prototype.makeImage = function () {
if (this._bIsPainted) {
_safeSetDataURI.call(this, _onMakeImage);
}
};
/**
* Return whether the QRCode is painted or not
*
* @return {Boolean}
*/
Drawing.prototype.isPainted = function () {
return this._bIsPainted;
};
/**
* Clear the QRCode
*/
Drawing.prototype.clear = function () {
this._oContext.clearRect(0, 0, this._elCanvas.width, this._elCanvas.height);
this._bIsPainted = false;
};
/**
* @private
* @param {Number} nNumber
*/
Drawing.prototype.round = function (nNumber) {
if (!nNumber) {
return nNumber;
}
return Math.floor(nNumber * 1000) / 1000;
};
return Drawing;
})();
/**
* Get the type by string length
*
* @private
* @param {String} sText
* @param {Number} nCorrectLevel
* @return {Number} type
*/
function _getTypeNumber(sText, nCorrectLevel) {
var nType = 1;
var length = _getUTF8Length(sText);
for (var i = 0, len = QRCodeLimitLength.length; i <= len; i++) {
var nLimit = 0;
switch (nCorrectLevel) {
case QRErrorCorrectLevel.L :
nLimit = QRCodeLimitLength[i][0];
break;
case QRErrorCorrectLevel.M :
nLimit = QRCodeLimitLength[i][1];
break;
case QRErrorCorrectLevel.Q :
nLimit = QRCodeLimitLength[i][2];
break;
case QRErrorCorrectLevel.H :
nLimit = QRCodeLimitLength[i][3];
break;
}
if (length <= nLimit) {
break;
} else {
nType++;
}
}
if (nType > QRCodeLimitLength.length) {
throw new Error("Too long data");
}
return nType;
}
function _getUTF8Length(sText) {
var replacedText = encodeURI(sText).toString().replace(/\%[0-9a-fA-F]{2}/g, 'a');
return replacedText.length + (replacedText.length != sText ? 3 : 0);
}
/**
* @class QRCode
* @constructor
* @example
* new QRCode(document.getElementById("test"), "http://jindo.dev.naver.com/collie");
*
* @example
* var oQRCode = new QRCode("test", {
* text : "http://naver.com",
* width : 128,
* height : 128
* });
*
* oQRCode.clear(); // Clear the QRCode.
* oQRCode.makeCode("http://map.naver.com"); // Re-create the QRCode.
*
* @param {HTMLElement|String} el target element or 'id' attribute of element.
* @param {Object|String} vOption
* @param {String} vOption.text QRCode link data
* @param {Number} [vOption.width=256]
* @param {Number} [vOption.height=256]
* @param {String} [vOption.colorDark="#000000"]
* @param {String} [vOption.colorLight="#ffffff"]
* @param {QRCode.CorrectLevel} [vOption.correctLevel=QRCode.CorrectLevel.H] [L|M|Q|H]
*/
QRCode = function (el, vOption) {
this._htOption = {
//二维码大小
width : 256,
height : 256,
typeNumber : 4,
colorDark : "#000000",
colorLight : "#ffffff",
correctLevel : QRErrorCorrectLevel.H,
//二维码中间图标
iconSrc: undefined,
iconBorderWidth: 0,
iconBorderColor: "black",
//幕布图片
curtainImg: undefined,
curtainBgColor: undefined,
//整个画布大小，边框充满整个画布
curtainWidth: undefined,
curtainHeight: undefined,
//二维码相对画布或边框图片的偏移
qrcodeOffsetX: undefined,
qrcodeOffsetY: undefined,
};
if (typeof vOption === 'string') {
vOption = {
text : vOption
};
}
// Overwrites options
if (vOption) {
for (var i in vOption) {
this._htOption[i] = vOption[i];
}
}
if (typeof el == "string") {
el = document.getElementById(el);
}
if (this._htOption.useSVG) {
Drawing = svgDrawer;
}
this._android = _getAndroid();
this._el = el;
this._oQRCode = null;
this._oDrawing = new Drawing(this._el, this._htOption);
if (this._htOption.text) {
this.makeCode(this._htOption.text);
}
};
/**
* Make the QRCode
*
* @param {String} sText link data
*/
QRCode.prototype.makeCode = async function (sText) {
this._oQRCode = new QRCodeModel(_getTypeNumber(sText, this._htOption.correctLevel), this._htOption.correctLevel);
this._oQRCode.addData(sText);
this._oQRCode.make();
this._el.title = sText;
const offsetExists = typeof(this._htOption.qrcodeOffsetX) !== "undefined" && typeof(this._htOption.qrcodeOffsetY) !== "undefined";
const curtainExists = typeof(this._htOption.curtainWidth) !== "undefined" && typeof(this._htOption.curtainHeight) !== "undefined";
const curtainImgExists = typeof(this._htOption.curtainImg) !== "undefined";
const curtainBgColorExists = typeof this._htOption.curtainBgColor !== "undefined" && curtainExists;
if(curtainBgColorExists) {
//如果不填充白色，下载下来的图片默认为透明色，很难看
this._oDrawing._oContext.fillStyle = this._htOption.curtainBgColor ? this._htOption.curtainBgColor : "white";
this._oDrawing._oContext.fillRect(0, 0, this._htOption.curtainWidth, this._htOption.curtainHeight);
this._oDrawing._oContext.save();
}
if(offsetExists) {
const x = this._htOption.qrcodeOffsetX;
const y = this._htOption.qrcodeOffsetY;
this._oDrawing._oContext.save();
this._oDrawing._oContext.translate(x, y);
}
if(curtainBgColorExists) {
this._oDrawing._oContext.rect(0,0,this._htOption.width,this._htOption.height);
this._oDrawing._oContext.clip();
}
this._oDrawing.draw(this._oQRCode);
if(typeof(this._htOption.iconSrc) !== "undefined") {
//这里是异步的函数，只有加了await才会变成同步（注意：即使函数里面有await，这个函数也是异步执行的）
await this._oDrawing.addIcon(this._htOption.iconSrc);
}
if(curtainBgColorExists) {
this._oDrawing._oContext.restore();
}
if(offsetExists) {
this._oDrawing._oContext.restore();
}
if(curtainImgExists) {
await this._oDrawing.addCurtain(this._htOption.curtainImg);
}
this.makeImage();
};
/**
* Make the Image from Canvas element
* - It occurs automatically
* - Android below 3 doesn't support Data-URI spec.
*
* @private
*/
QRCode.prototype.makeImage = function () {
if (typeof this._oDrawing.makeImage == "function" && (!this._android || this._android >= 3)) {
this._oDrawing.makeImage();
}
};
/**
* Clear the QRCode
*/
QRCode.prototype.clear = function () {
this._oDrawing.clear();
};
/**
* @name QRCode.CorrectLevel
*/
QRCode.CorrectLevel = QRErrorCorrectLevel;
})();
