本文实例为大家分享了jQuery实现移动端笔触canvas电子签名的具体代码，供大家参考，具体内容如下

本文主要是通过jq实现电子签名，其中ios有一个坑，已修复。基于mui+vue框架实现的，如果使用此框架，稍稍改动代码即可。

1.相关代码

1.1引入jq

<script src="jquery-1.11.0.min.js" type="text/javascript"></script>

1.2封装signature.js

(function(window, document, $) { 'use strict'; // Get a regular interval for drawing to the screen window.requestAnimFrame = (function (callback) { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimaitonFrame || function (callback) { window.setTimeout(callback, 1000/60); }; })(); /* * Plugin Constructor */ var pluginName = 'jqSignature', defaults = { lineColor: '#222222', lineWidth: 1, border: '1px dashed #AAAAAA', background: '#FFFFFF', width: 375, height: 200, autoFit: false }, canvasFixture = '<canvas></canvas>'; function Signature(element, options) { // DOM elements/objects this.element = element; this.$element = $(this.element); this.canvas = false; this.$canvas = false; this.ctx = false; // Drawing state this.drawing = false; this.currentPos = { x: 0, y: 0 }; this.lastPos = this.currentPos; // Determine plugin settings this._data = this.$element.data(); this.settings = $.extend({}, defaults, options, this._data); // Initialize the plugin this.init(); } Signature.prototype = { // Initialize the signature canvas init: function() { // Set up the canvas this.$canvas = $(canvasFixture).appendTo(this.$element); this.$canvas.attr({ width: this.settings.width, height: this.settings.height }); this.$canvas.css({ boxSizing: 'border-box', width: this.settings.width + 'px', height: this.settings.height + 'px', border: this.settings.border, background: this.settings.background, cursor: 'crosshair' }); // Fit canvas to width of parent if (this.settings.autoFit === true) { this._resizeCanvas(); // TO-DO - allow for dynamic canvas resizing // (need to save canvas state before changing width to avoid getting cleared) var timeout = false; $(window).on('resize', $.proxy(function(e) { clearTimeout(timeout); timeout = setTimeout($.proxy(this._resizeCanvas, this), 250); }, this)); } this.canvas = this.$canvas[0]; this._resetCanvas(); // Set up mouse events this.$canvas.on('mousedown touchstart', $.proxy(function(e) { this.drawing = true; this.lastPos = this.currentPos = this._getPosition(e); }, this)); this.$canvas.on('mousemove touchmove', $.proxy(function(e) { this.currentPos = this._getPosition(e); }, this)); this.$canvas.on('mouseup touchend', $.proxy(function(e) { this.drawing = false; // Trigger a change event var changedEvent = $.Event('jq.signature.changed'); this.$element.trigger(changedEvent); }, this)); // Prevent document scrolling when touching canvas $(document).on('touchstart touchmove touchend', $.proxy(function(e) { if (e.target === this.canvas) { e.preventDefault(); } }, this)); // Start drawing var that = this; (function drawLoop() { window.requestAnimFrame(drawLoop); that._renderCanvas(); })(); }, // Clear the canvas clearCanvas: function() { this.canvas.width = this.canvas.width; this._resetCanvas(); }, // Get the content of the canvas as a base64 data URL getDataURL: function() { return this.canvas.toDataURL(); }, // Get the position of the mouse/touch _getPosition: function(event) { var u = navigator.userAgent; var isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端 var xPos, yPos, rect, getRect; rect = this.canvas.getBoundingClientRect(); event = event.originalEvent; // Touch event if (event.type.indexOf('touch') !== -1) { // event.constructor === TouchEvent xPos = event.touches[0].clientX - rect.left; yPos = event.touches[0].clientY - 50; $('#yPos').html('<p><em>当您点击“保存签名”时，W您的签名将出现在这里'+yPos+','+rect.top+','+rect.bottom+'</em></p>'); } // Mouse event else { xPos = event.clientX - rect.left; yPos = event.clientY - rect.top; $('#yPos').html(yPos); } return { x: xPos, y: yPos// y: isIOS?1.7*yPos:yPos }; }, // Render the signature to the canvas _renderCanvas: function() { if (this.drawing) { this.ctx.moveTo(this.lastPos.x, this.lastPos.y); this.ctx.lineTo(this.currentPos.x, this.currentPos.y); this.ctx.stroke(); this.lastPos = this.currentPos; } }, // Reset the canvas context _resetCanvas: function() { this.ctx = this.canvas.getContext("2d"); this.ctx.strokeStyle = this.settings.lineColor; this.ctx.lineWidth = this.settings.lineWidth; }, // Resize the canvas element _resizeCanvas: function() { var width = this.$element.outerWidth(); this.$canvas.attr('width', width); this.$canvas.css('width', width + 'px'); } }; /* * Plugin wrapper and initialization */ $.fn[pluginName] = function ( options ) { var args = arguments; if (options === undefined || typeof options === 'object') { return this.each(function () { if (!$.data(this, 'plugin_' + pluginName)) { $.data(this, 'plugin_' + pluginName, new Signature( this, options )); } }); } else if (typeof options === 'string' && options[0] !== '_' && options !== 'init') { var returns; this.each(function () { var instance = $.data(this, 'plugin_' + pluginName); if (instance instanceof Signature && typeof instance[options] === 'function') { returns = instance[options].apply( instance, Array.prototype.slice.call( args, 1 ) ); } if (options === 'destroy') { $.data(this, 'plugin_' + pluginName, null); } }); return returns !== undefined ? returns : this; } };})(window, document, jQuery);

1.3DOM页面index.html

<div class="signature-wrapper" v-show="isSignature" :class="isSignature?'isSignature':''"> <header class="mui-bar mui-bar-nav head-color"> <a class="mui-icon mui-icon-back mui-pull-left" @tap="closeSignature"></a> <h1 class="mui-title">签名</h1> <a id="menu" class="mui-icon mui-pull-right menu-btn" @tap="saveSignature">保存</a> </header> <div class="container"> <div class="row"> <div class="col-xs-12"> <div class="js-signature" data-width="600" data-height="200" data-border="1px solid black" data-line-color="#000000" data-auto-fit="true"></div> <p><button id="clearBtn" class="btn btn-default" @tap="clearCanvas();">重置签名</button>&nbsp;<button id="saveBtn" class="btn btn-default" @tap="previewSignature();" disabled>保存签名</button></p> <div id="signature"> <p><em>当您点击“保存签名”时，您的签名将出现在这里</em></p> </div> <span id="yPos"><p><em>ypos</em></p></span> </div> </div> </div></div>

1.4JS

注：由于此次的$被模型其他框架所替换，因此以jq替代

mounted: function() {this.$nextTick(function() { this.init(); });},methods:{ init: function() { jq('.js-signature').eq(0).on('jq.signature.changed', function() { //canvas签名 初始化 jq('#saveBtn').attr('disabled', false); }); }},clearCanvas:function(){ // 清除重置签名 jq('#signature').html('<p><em>当您点击“保存签名”时，您的签名将出现在这里</em></p>'); jq('.js-signature').eq(0).jqSignature('clearCanvas'); jq('#saveBtn').attr('disabled', true); vm.signatureImg="";},previewSignature:function(){ //保存签名 jq('#signature').empty(); var dataUrl = jq('.js-signature').eq(0).jqSignature('getDataURL'); var img = jq('<img>').attr('src', dataUrl); jq('#signature').append(img); console.log(dataUrl) vm.signatureImg=dataUrl;},saveSignature:function(){ // 保存按钮 逻辑if(!vm.signatureImg){ $.toast("请先保存签名"); return; } vm.closeSignature();},closeSignature:function(){// 关闭签名弹出层 vm.isSignature = false; },openSignature:function(){ // 打开签名弹出层 vm.isSignature = true; this.$nextTick(function() { if ($('.js-signature').length) { jq('.js-signature').jqSignature(); } });}

2.页面效果图如下

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。