详解HTML5中canvas支持触摸屏的签名面板的示例代码
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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">×</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();
}
};
}以上就是详解HTML5中canvas支持触摸屏的签名面板的示例代码的详细内容，更多请关注Gxl网其它相关文章！
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