jSignature 插件实现手写电子签名

需求：需要在合同的最后加一个签名区，让用户能用鼠标或手指进行签名。

解决方案：jSignature 插件，依赖jquery。

index.html

    //#canvasDiv 就是书写区域，img 是书写完成后转为图片<div class="person" style="">乙方(持卡人及卡片使用人签字)：</br><div id="canvasDiv"></div><button id="btn_clear" style="">重写</button><button id="btn_submit">确定</button><img id="qmimg" /></div>

index.js

<script src="./js/jquery-2.1.4.min.js"></script><script src="./js/jSignature.min.js"></script><script>$(function () {var param = {width: '400px', //签名区域的宽height: '100px', //签名区域的高// cssclass: 'cans', //画布的类 可以写自定义的样式UndoButton: true, //撤销按钮的状态 这个按钮的样式修改要去jSignature.js文件中去找signatureLine: false, //去除默认画布上那条横线lineWidth: '1' //画笔的大小};//初始化$("#canvasDiv").jSignature(param);//jSignature提供了清除的API reset$('#btn_clear').click(function () {$("#canvasDiv").jSignature("reset");});//确认$('#btn_submit').click(function () {//获取签名生成的图片 默认是png的var datapair = $("#canvasDiv").jSignature("getData", "image");var i = new Image();i.src = "data:" + datapair[0] + "," + datapair[1];i.image = datapair[1];// console.log(i.image);//i.image 是一串字符串$('#qmimg').attr('src',`data:image/png;base64,${i.image}`);$("#canvasDiv").hide();$("#btn_clear").hide();$("#btn_submit").hide();})})</script>

jSignature.min.js 文件，https://github.com/brinley/jSignature 这是github上的地址，也有这个文件

/*jSignature v2 "2018-11-06T13:56" "commit ID 89c22b348ab2e1d92a928d8fd992f175e8bc5cbd"
Copyright (c) 2012 Willow Systems Corp http://willow-systems.com
Copyright (c) 2010 Brinley Ang http://www.unbolt.net
MIT License <http://www.opensource.org/licenses/mit-license.php>Simplify.js BSD
(c) 2012, Vladimir Agafonkin
mourner.github.com/simplify-jsbase64 encoder
MIT, GPL
http://phpjs.org/functions/base64_encode
+   original by: Tyler Akins (http://rumkin.com)
+   improved by: Bayron Guevara
+   improved by: Thunder.m
+   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
+   bugfixed by: Pellentesque Malesuada
+   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
+   improved by: Rafal Kukawski (http://kukawski.pl)jSignature v2 jSignature's Undo Button and undo functionality pluginjSignature v2 jSignature's custom "base30" format export and import plugins.jSignature v2 SVG export plugin.*/
(function(){function q(a){var b=a.css("color"),c;a=a[0];for(var g=!1;a&&!c&&!g;){try{var d=$(a).css("background-color")}catch(l){d="transparent"}"transparent"!==d&&"rgba(0, 0, 0, 0)"!==d&&(c=d);g=a.body;a=a.parentNode}a=/rgb[a]*\((\d+),\s*(\d+),\s*(\d+)/;g=/#([AaBbCcDdEeFf\d]{2})([AaBbCcDdEeFf\d]{2})([AaBbCcDdEeFf\d]{2})/;d=void 0;if(d=b.match(a))var m={r:parseInt(d[1],10),g:parseInt(d[2],10),b:parseInt(d[3],10)};else(d=b.match(g))&&(m={r:parseInt(d[1],16),g:parseInt(d[2],16),b:parseInt(d[3],16)});
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this.canvasContext=b.getContext("2d");c.data("jSignature.this",this);e.lineWidth=function(a,b){return a?a:Math.max(Math.round(b/400),2)}(e.lineWidth,b.width);this.lineCurveThreshold=3*e.lineWidth;e.cssclass&&""!=$.trim(e.cssclass)&&c.addClass(e.cssclass);this.fatFingerCompensation=0;g=function(a){var b,c,d=function(d){d=d.changedTouches&&0<d.changedTouches.length?d.changedTouches[0]:d;return new h(Math.round(d.pageX+b),Math.round(d.pageY+c)+a.fatFingerCompensation)},g=new v(750,function(){a.dataEngine.endStroke()});
this.drawEndHandler=function(b){if(!a.settings.readOnly){try{b.preventDefault()}catch(A){}g.clear();a.dataEngine.endStroke()}};this.drawStartHandler=function(e){if(!a.settings.readOnly){e.preventDefault();var m=$(a.canvas).offset();b=-1*m.left;c=-1*m.top;a.dataEngine.startStroke(d(e));g.kick()}};this.drawMoveHandler=function(b){a.settings.readOnly||(b.preventDefault(),a.dataEngine.inStroke&&(a.dataEngine.addToStroke(d(b)),g.kick()))};return this}.call({},this);(function(a,b,c){var d=this.canvas,g=
$(d);if(this.isCanvasEmulator)g.bind("mousemove.jSignature",c),g.bind("mouseup.jSignature",a),g.bind("mousedown.jSignature",b);else{var m="function"===typeof d.addEventListener;this.ontouchstart=function(g){d.onmousedown=d.onmouseup=d.onmousemove=void 0;this.fatFingerCompensation=e.minFatFingerCompensation&&-3*e.lineWidth>e.minFatFingerCompensation?-3*e.lineWidth:e.minFatFingerCompensation;b(g);m?(d.addEventListener("touchend",a),d.addEventListener("touchstart",b),d.addEventListener("touchmove",c)):
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(function(){function q(k,h,p){k=k.call(this);(function(h,k,p){h.events.subscribe(p+".change",function(){h.dataEngine.data.length?k.show():k.hide()})})(this,k,h);(function(h,k,p){var n=p+".undo";k.bind("click",function(){h.events.publish(n)});h.events.subscribe(n,function(){var k=h.dataEngine.data;k.length&&(k.pop(),h.resetCanvas(k))})})(this,k,this.events.topics.hasOwnProperty(h+".undo")?p:h)}$.fn.jSignature("addPlugin","instance","UndoButton",function(k){this.events.subscribe("jSignature.attachingEventHandlers",
function(){if(this.settings[k]){var h=this.settings[k];"function"!==typeof h&&(h=function(){var h=$('<input type="button" value="Undo last stroke" style="position:absolute;display:none;margin:0 !important;top:auto" />').appendTo(this.$controlbarLower),k=h.width();h.css("left",Math.round((this.canvas.width-k)/2));k!==h.width()&&h.width(k);return h});q.call(this,h,"jSignature",k)}})})})();
(function(){for(var q={},k={},h="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWX".split(""),p=h.length/2,n=p-1;-1<n;n--)q[h[n]]=h[n+p],k[h[n+p]]=h[n];var w=function(e){e=e.split("");for(var a=e.length,b=1;b<a;b++)e[b]=q[e[b]];return e.join("")},x=function(e){for(var a=[],b=0,c=1,g=e.length,d,f,h=0;h<g;h++)d=Math.round(e[h]),f=d-b,b=d,0>f&&0<c?(c=-1,a.push("Z")):0<f&&0>c&&(c=1,a.push("Y")),d=Math.abs(f),d>=p?a.push(w(d.toString(p))):a.push(d.toString(p));return a.join("")},v=function(e){var a=
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u(e)]},f=function(e,a,b){"string"===typeof e&&("image/jsignature;base30"===e.substring(0,23).toLowerCase()&&(e=e.substring(24)),b(y(e)))};if(null==this.jQuery)throw Error("We need jQuery for some of the functionality. jQuery is not detected. Failing to initialize...");(function(e){e=e.fn.jSignature;e("addPlugin","export","base30",C);e("addPlugin","export","image/jsignature;base30",C);e("addPlugin","import","base30",f);e("addPlugin","import","image/jsignature;base30",f)})(this.jQuery);this.jSignatureDebug&&
(this.jSignatureDebug.base30={remapTailChars:w,compressstrokeleg:x,uncompressstrokeleg:v,compressstrokes:u,uncompressstrokes:y,charmap:q})}).call("undefined"!==typeof window?window:this);
(function(){function q(f,e){this.x=f;this.y=e;this.reverse=function(){return new this.constructor(-1*this.x,-1*this.y)};this._length=null;this.getLength=function(){this._length||(this._length=Math.sqrt(Math.pow(this.x,2)+Math.pow(this.y,2)));return this._length};var a=function(a){return Math.round(a/Math.abs(a))};this.resizeTo=function(b){if(0===this.x&&0===this.y)this._length=0;else if(0===this.x)this._length=b,this.y=b*a(this.y);else if(0===this.y)this._length=b,this.x=b*a(this.x);else{var c=Math.abs(this.y/
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g)*f),c=(new q(b.x+c.x,b.y+c.y)).reverse().resizeTo(Math.max(.05,e)*f),c=new q(b.x+c.x,b.y+c.y),["c",h(a.x,2),h(a.y,2),h(c.x,2),h(c.y,2),h(b.x,2),h(b.y,2)]):["l",h(b.x,2),h(b.y,2)]}function n(f,e){var a=f.x.length-1,b=new k(f.x[a],f.y[a]),c=new k(f.x[a-1],f.y[a-1]);b=c.getVectorToPoint(b);if(1<a&&b.getLength()>e){a=(new k(f.x[a-2],f.y[a-2])).getVectorToPoint(c);c=b.angleTo(a.reverse());var g=.35*b.getLength();a=(new q(a.x+b.x,a.y+b.y)).resizeTo(Math.max(.05,c)*g);return["c",h(a.x,2),h(a.y,2),h(b.x,
2),h(b.y,2),h(b.x,2),h(b.y,2)]}return["l",h(b.x,2),h(b.y,2)]}function w(f,e,a){e=["M",h(f.x[0]-e,2),h(f.y[0]-a,2)];a=1;for(var b=f.x.length-1;a<b;a++)e.push.apply(e,p(f,a,1));0<b?e.push.apply(e,n(f,a,1)):0===b&&e.push.apply(e,["l",1,1]);return e.join(" ")}function x(f){for(var e=[],a=[["fill",void 0,"none"],["stroke","color","#000000"],["stroke-width","lineWidth",2],["stroke-linecap",void 0,"round"],["stroke-linejoin",void 0,"round"]],b=a.length-1;0<=b;b--){var c=a[b][1],g=a[b][2];e.push(a[b][0]+
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f-3):e)+"===".slice(f||3)};if("undefined"===typeof $)throw Error("We need jQuery for some of the functionality. jQuery is not detected. Failing to initialize...");(function(f){f=f.fn.jSignature;f("addPlugin","export","svg",u);f("addPlugin","export","image/svg+xml",u);f("addPlugin","export","svgbase64",y);f("addPlugin","export","image/svg+xml;base64",y)})($)})();

总结：一开始有用过其他方法处理这个问题，那个方法最造成的问题是：在移动端放大页面来进行签名，签名区的滑动会导致整个页面进行滑动。
这个插件解决了这个问题。

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jSignature 插件实现手写电子签名

需求：需要在合同的最后加一个签名区，让用户能用鼠标或手指进行签名。

解决方案：jSignature 插件，依赖jquery。

index.html

index.js

jSignature.min.js 文件，https://github.com/brinley/jSignature 这是github上的地址，也有这个文件

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