HTML5中canvas支持触摸屏的签名面板

2019-11-14 15:43:56

字体：大中小

来源：转载

供稿：网友

1.前言

最近实在是太忙了，从国庆之后的辞职，在慢慢的找工作，到今天在现在的这家公司上班大半个月了，太多的心酸泪无以言表，面试过程中，见到的坑货公司是一家又一家，好几家公司自己都只是上一天班就走了，其中有第一天上班就加班到10点的，有一家公司在体育西路那边，太远，第一天回家挤公交也是太累，以前上班都是走路上班的，自己确实不适合挤公交，还有的公司面试的时候和你说什么大数据，性能优化什么的，进公司一看，他们就是用的最简单的三层，没有什么设计模式，总之太多心酸，幸运的是现在这家公司还不错，找工作就是要宁缺毋滥。

2.canvcas标签

canvas基础教程：<canvas> 标签定义图形，比如图表和其他图像。HTML5 的 canvas 元素使用 javaScript 在网页上绘制图像。甚至可以在 canvas 上创建并操作动画，这不是使用画笔和油彩所能够实现的。跨所有 web 浏览器的完整 HTML5 支持还没有完成，但在新兴的支持中，canvas 已经可以在几乎所有现代浏览器上良好运行。canvas 拥有多种绘制路径、矩形、圆形、字符以及添加图像的方法。来公司一个月了主要也是学习为主，我是做后台开发，以前也没有用过Oracle 数据库，这一个月也主要是学习H5的一些新特新，还有就是CSS3.0，在就是Oracle在服务器上面的安装部署，一些数据导入导出，数据备份啥的，前端的东西都比较差，现在也是一个学习的机会，就当好好学习了。

3.手写签名面板

公司做的是自动化办公OA系统，一些审核的地方需要加入一些手写签名的功能，刚开始做这个也是没有思路，在网上也找了一下资料，后来发现H5有这个canvcas新标签，感到格外是欣喜。于是拿过来试一下，还真可以。

4.页面代码

@{    Layout = null;}<!DOCTYPE html><html><head>    <meta name="viewport" content="width=device-width" />    <title>Testpage</title>    <script src="~/Assets/jquery-2.1.1.js"></script>    <script src="~/Assets/bootstrap/bootstrap.js"></script>    <link href="~/Assets/bootstrap/bootstrap.css" rel="stylesheet" />    <script src="~/Scripts/WritingPad.js"></script>    <script src="~/Assets/jq-signature.js"></script></head><body style="background-color:#b6ff00">    <button class="btn btn-PRimary" type="button" style="position:relative">点击我</button></body></html><script>    $(function () {        $(".btn,.btn-primary").click(function () {            var wp = new WritingPad();            //wp.init();        });    });</script>

5.脚本代码一

/** * 功能：签名canvas面板初始化,为WritingPad.js手写面板js服务。 * 作者：黄金锋 (549387177@QQ.com) * 日期：2015-11-15  15:51:01 * 版本：version 1.0 */(function (window, document, $) {    'use strict';  // Get a regular interval for drawing to the screen  window.requestAnimFrame = (function (callback) {    return window.requestAnimationFrame ||       window.webkitRequestAnimationFrame ||      window.mozRequestAnimationFrame ||      window.oRequestAnimationFrame ||      window.msRequestAnimaitonFrame ||      function (callback) {        window.setTimeout(callback, 1000/60);      };  })();  /*  * Plugin Constructor  */  var pluginName = 'jqSignature',      defaults = {        lineColor: '#222222',        lineWidth: 1,        border: '1px dashed #CCFF99',        background: '#FFFFFF',        width: 500,        height: 200,        autoFit: false      },      canvasFixture = '<canvas></canvas>';  function Signature(element, options) {    // DOM elements/objects    this.element = element;    this.$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();      }      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', $.proxy(function(e) {        if (e.target === this.canvas) {          e.preventDefault();        }      }, this));      // Start drawing      var that = this;      (function drawLoop() {        window.requestAnimFrame(drawLoop);        that._renderCanvas();      })();    },    // Clear the canvas    clearCanvas: function() {      this.canvas.width = this.canvas.width;      this._resetCanvas();    },    // Get the content of the canvas as a base64 data URL    getDataURL: function() {      return this.canvas.toDataURL();    },    reLoadData: function () {        this.$canvas.remove();        this._data = this.$element.data();        //for (var i in this.settings) {        //    alert(i+":"+this.settings[i]);        //}        //this.settings = $.extend({}, defaults, this._data);        this.init();    },    // Get the position of the mouse/touch    _getPosition: function(event) {      var xPos, yPos, rect;      rect = this.canvas.getBoundingClientRect();      event = event.originalEvent;      // Touch event      if (event.type.indexOf('touch') !== -1) { // event.constructor === TouchEvent        xPos = event.touches[0].clientX - rect.left;        yPos = event.touches[0].clientY - rect.top;      }      // Mouse event      else {        xPos = event.clientX - rect.left;        yPos = event.clientY - rect.top;      }      return {        x: xPos,        y: yPos      };    },    // Render the signature to the canvas    _renderCanvas: function() {      if (this.drawing) {        this.ctx.moveTo(this.lastPos.x, this.lastPos.y);        this.ctx.lineTo(this.currentPos.x, this.currentPos.y);        this.ctx.stroke();        this.lastPos = this.currentPos;      }    },    // Reset the canvas context    _resetCanvas: function() {      this.ctx = this.canvas.getContext("2d");      this.ctx.strokeStyle = this.settings.lineColor;      this.ctx.lineWidth = this.settings.lineWidth;    },    // Resize the canvas element    _resizeCanvas: function() {      var width = this.$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') {            var myArr=Array.prototype.slice.call( args, 1 );            returns = instance[options].apply(instance, myArr);        }        if (options === 'destroy') {          $.data(this, 'plugin_' + pluginName, null);        }        //if (options === 'reLoadData') {        //    //this.$canvas.remove();        //    $.data(this, 'plugin_' + pluginName, null);        //    this._data = this.$element.data();        //    this.settings = $.extend({}, defaults, options, this._data);        //    this.init();        //}      });      return returns !== undefined ? returns : this;    }  };})(window, document, jQuery);

6.脚本代码二

/** * 功能：使用该jQuery插件来制作在线签名或涂鸦板，用户绘制的东西可以用图片的形式保存下来。 * 作者：黄金锋 (549387177@qq.com) * 日期：2015-11-16  13:51:01 * 版本：version 1.0 */var WritingPad = function () {    var current = null;    $(function () {        initHtml();        initTable();        initSignature();        if ($(".modal")) {            $(".modal").modal("toggle");        } else {            alert("没用手写面板");        }        $(document).on("click", "#myClose,.close", null, function () {            $('#mymodal').modal('hide');            $("#mymodal").remove();        });        $(document).on("click", "#mySave", null, function () {            var myImg = $('#myImg').empty();            var dataUrl = $('.js-signature').jqSignature('getDataURL');            var img = $('<img>').attr('src', dataUrl);            $(myImg).append($('<p>').text("图片保存在这里"));            $(myImg).append(img);        });        $(document).on("click", "#myEmpty", null, function () {            $('.js-signature').jqSignature('clearCanvas');        });        $(document).on("click", "#myBackColor", null, function () {            $('#colorpanel').css('left', '95px').css('top', '45px').css("display", "block").fadeIn();            //$("canvas").css("background", "#EEEEEE");            $("#btnSave").data("sender", "#myBackColor");        });        $(document).on("click", "#myColor", null, function () {            $('#colorpanel').css('left', '205px').css('top', '45px').css("display", "block").fadeIn();            $("#btnSave").data("sender", "#myColor");        });        $(document).on("mouSEOver", "#myTable", null, function () {            if ((event.srcElement.tagName == "TD") && (current != event.srcElement)) {                if (current != null) { current.style.backgroundColor = current._background }                event.srcElement._background = event.srcElement.style.backgroundColor;                //$("input[name=DisColor]").css("background-color", event.srcElement.style.backgroundColor);                //var color = event.srcElement.style.backgroundColor;                //var strArr = color.substring(4, color.length - 1).split(',');                //var num = showRGB(strArr);                //$("input[name=HexColor]").val(num);                current = event.srcElement;            }        });        $(document).on("mouseout", "#myTable", null, function () {            if (current != null) current.style.backgroundColor = current._background        });        $(document).on("click", "#myTable", null, function () {            if (event.srcElement.tagName == "TD") {                var color = event.srcElement._background;                if (color) {                    $("input[name=DisColor]").css("background-color", color);                    var strArr = color.substring(4, color.length - 1).split(',');                    var num = showRGB(strArr);                    $("input[name=HexColor]").val(num);                }            }        });        $(document).on("click", "#btnSave", null, function () {            $('#colorpanel').css("display", "none");            var typeData = $("#btnSave").data("sender");            var HexColor = $("input[name=HexColor]").val();            var data = $(".js-signature").data();            if (typeData == "#myColor") {                data["plugin_jqSignature"]["settings"]["lineColor"] = HexColor;                $('.js-signature').jqSignature('reLoadData');            }            if (typeData == "#myBackColor") {                data["plugin_jqSignature"]["settings"]["background"] = HexColor;                $('.js-signature').jqSignature('reLoadData');            }        });        $("#mymodal").on('hide.bs.modal', function () {            $("#colorpanel").remove();            $("#mymodal").remove();            $("#myTable").remove();        });    });    function initHtml() {        var html = '<div class="modal" id="mymodal">' +            '<div class="modal-dialog">' +                '<div class="modal-content">' +                    '<div class="modal-header">' +                        '<button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span></button>' +                        '<h4 class="modal-title">手写面板</h4>' +                    '</div>' +                    '<div class="modal-body">' +                        '<div class="js-signature" id="mySignature">' +                         '</div>' +                         '<div>' +                         '<button type="button" class="btn btn-default" id="myEmpty">清空面板</button>' +                         '<button type="button" class="btn btn-default" id="myBackColor">设置背景颜色</button>' +                         //'<div style="position:absolute;relative">' +                         '<button type="button" class="btn btn-default" id="myColor">设置字体颜色</button>' +                         '<div id="colorpanel" style="position:absolute;z-index:99;display:none"></div>' +                         //'</div>'+                         '</div>' +                    '</div>' +                    '<div class="modal-footer">' +                        '<button type="button" class="btn btn-default" id="myClose">关闭</button>' +                        '<button type="button" class="btn btn-primary" id="mySave">保存</button>' +                        '<div id="myImg">' +                        '<div>' +                    '</div>' +                '</div>' +            '</div>' +        '</div>';        $('body').append(html);    }    function initTable() {        var colorTable = "";        var ColorHex = new Array('00', '33', '66', '99', 'CC', 'FF');        var SpColorHex = new Array('FF0000', '00FF00', '0000FF', 'FFFF00', '00FFFF', 'FF00FF');        for (var i = 0; i < 2; i++)        {            for (var j = 0; j < 6; j++)            {                colorTable = colorTable + '<tr height=12>';                colorTable = colorTable + '<td width=11 style="background-color:#000000"></td>';                if (i == 0)                {                    colorTable = colorTable + '<td width=11 style="background-color:#' + ColorHex[j] + ColorHex[j] + ColorHex[j] + '"></td>';                }                else                {                    colorTable = colorTable + '<td width=11 style="background-color:#' + SpColorHex[j] + '"></td>';                }                //colorTable = colorTable + '<td width=11 style="background-color:#000000"></td>';                for (var k = 0; k < 3; k++)                {                    for (l = 0; l < 6; l++)                    {                        colorTable = colorTable + '<td width=11 style="background-color:#' + ColorHex[k + i * 3] + ColorHex[l] + ColorHex[j] + '"></td>';                    }                }                colorTable = colorTable + '</tr>';            }        }        colorTable =        '<table border="1" id="myTable" cellspacing="0" cellpadding="0" style="border-collapse: collapse;cursor:pointer;" bordercolor="000000">'        + colorTable + '</table>' +        '<table width=225 border="0" cellspacing="0" cellpadding="0" style="border:1px #000000 solid;border-collapse: collapse;background-color:#000000">' +        '<tr style="height:30px">' +        '<td colspan=21 bgcolor=#cccccc>' +        '<table cellpadding="0" cellspacing="1" border="0" style="border-collapse: collapse">' +        '<tr>' +        '<td width="3"><input type="text" name="DisColor" size="6" disabled style="border:solid 1px #000000;background-color:#ffff00"></td>' +        '<td width="3"><input type="text" name="HexColor" size="7" style="border:inset 1px;font-family:Arial;" value="#000000"></td>' +         '<td width="3"><button type="button" class="btn btn-primary btn-sm" id="btnSave">确认</button></td>' +        '</tr>' +        '</table>' +               '</td>' +        '</tr>' +        '</table>';        $("#colorpanel").append(colorTable);    }    function initSignature() {        if (window.requestAnimFrame) {            var signature = $("#mySignature");            signature.jqSignature({ width: 500, height: 200, border: '1px solid red', background: '#16A085', lineColor: '#ABCDEF', lineWidth: 2, autoFit: false });            //{ width: 600, height: 200, border: '1px solid red', background: '#16A085', lineColor: '#ABCDEF', lineWidth: 2, autoFit: true }        } else {            alert("请加载jq-signature.js");            return;        }    }    function showRGB(arr) {        hexcode = "#";        for (x = 0; x < 3; x++) {            var n = arr[x];            if (n == "") n = "0";            if (parseInt(n) != n)                return alert("RGB颜色值不是数字！");            if (n > 255)                return alert("RGB颜色数字必须在0-255之间！");            var c = "0123456789ABCDEF", b = "", a = n % 16;            b = c.substr(a, 1); a = (n - a) / 16;            hexcode += c.substr(a, 1) + b        }        return hexcode;    }    function init() {    }    return {        init: function () {            init();        }    };}