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[js高手之路]html5 canvas动画教程,

[js高手之路]html5 canvas动画教程,这个绘图工具,我还没有做完,不过已经实现了总架构,以及常见的简易图形绘制功能: 1,可以绘制直线,圆,矩形,正多边形【已完成】 2,填充颜色和描边...

[js高手之路]html5 canvas动画教程,

这个绘图工具,我还没有做完,不过已经实现了总架构,以及常见的简易图形绘制功能:

1,可以绘制直线,圆,矩形,正多边形【已完成】

2,填充颜色和描边颜色的选择【已完成】

3,描边和填充功能的选择【已完成】

后续版本:

橡皮擦,坐标系,线形设置,箭头,其他流程图形,裁剪与调整图形。。。。。

终极目标:

流程绘制软件

我是之前看见一位朋友在我的博客中留言说:

非常感谢这个朋友,今天终于抽出时间完成非常非常小的雏形!

完整的雏形代码,请自行打开,复制到本地测试.

1 <head> 2 <meta charset="UTF-8"> 3 <meta name="viewport" content="width=device-width, initial-scale=1.0"> 4 <meta http-equiv="X-UA-Compatible" content="ie=edge"> 5 <title>windows简易画图工具 - by ghostwu</title> 6 </head> 7 8 <body> 9 <div class="paint"> 10 <div class="paint-header"> 11 <ul> 12 <li class="active">形状</li> 13 <li>颜色</li> 14 <li>绘制类型</li> 15 <li>线条宽度</li> 16 <li>橡皮擦</li> 17 </ul> 18 </div> 19 <div class="paint-body"> 20 <div class="siderbar"> 21 <div class="item active" data-type="paint-shape"> 22 <ul> 23 <li class="active" data-role="line">线条</li> 24 <li data-role="circle">圆形</li> 25 <li data-role="rect">矩形</li> 26 <li data-role="polygon">正多边形</li> 27 <li data-role="arrow">箭头</li> 28 </ul> 29 </div> 30 <div class="item" data-type="paint-color"> 31 <ul> 32 <li data-role="strokeStyle"> 33 <input type="color" data-role="strokeStyle"> 34 </li> 35 <li data-role="fillStyle"> 36 <input type="color" data-role="fillStyle"> 37 </li> 38 </ul> 39 </div> 40 <div class="item" data-type="paint-type"> 41 <ul> 42 <li data-role="stroke">描边</li> 43 <li data-role="fill">填充</li> 44 </ul> 45 </div> 46 <div class="item" data-type="paint-line"> 47 <ul> 48 <li data-role="1">小号</li> 49 <li data-role="4">中号</li> 50 <li data-role="7">大号</li> 51 <li> 52 <input type="number" data-role="line-size" placeholder="请输入数字"> 53 </li> 54 </ul> 55 </div> 56 <div class="item" data-type="paint-erase"> 57 <ul> 58 <li> 59 <input type="number" data-role="erase-size" placeholder="请输入数字"> 60 </li> 61 </ul> 62 </div> 63 </div> 64 </div> 65 </div> 66 <script>// <![CDATA[ 67 var oPaintBody = document.querySelector( ‘.paint-body‘ ); 68 var oC = document.createElement( ‘canvas‘ ); 69 oC.setAttribute( ‘width‘, ‘830‘ ); 70 oC.setAttribute( ‘height‘, ‘500‘ ); 71 oPaintBody.appendChild( oC ); 72 var aHeaderLi = document.querySelectorAll(‘.paint-header li‘), 73 aItem = document.querySelectorAll(‘.paint-body .item‘), 74 oCanvas = document.querySelector(‘.paint canvas‘), 75 oGc = oCanvas.getContext(‘2d‘), 76 cWidth = oCanvas.width, cHeight = oCanvas.height, 77 curItem = aItem[0], 78 aItemLi = curItem.querySelectorAll(‘li‘); 79 80 for (let i = 0, len = aHeaderLi.length; i < len; i++) { //头部选项卡切换功能 81 aHeaderLi[i].onclick = function () { 82 for (let j = 0; j < len; j++) { 83 aHeaderLi[j].classList.remove(‘active‘); 84 aItem[j].style.display = ‘none‘; 85 } 86 aItem[i].style.display = "block"; 87 this.classList.add(‘active‘); 88 curItem = aItem[i]; 89 aItemLi = curItem.querySelectorAll(‘li‘); 90 activeItem(aItemLi); 91 } 92 } 93 activeItem(aItemLi); 94 var role = null; 95 function activeItem(aItemLi) { //canvas左侧选项卡切换功能 96 for (let i = 0, len = aItemLi.length; i < len; i++) { 97 aItemLi[i].onclick = function () { 98 checkPaintType(this); //绘制类型 99 for (let j = 0; j < len; j++) { 100 aItemLi[j].classList.remove(‘active‘); 101 } 102 this.classList.add(‘active‘); 103 } 104 } 105 } 106 107 function Shape(canvasObj, cxtObj, w, h) { 108 this.oCanvas = canvasObj; 109 this.oGc = cxtObj; 110 this.oCanvas.width = w; 111 this.oCanvas.height = h; 112 this.fillStyle = ‘#000‘; 113 this.storkeStyle = ‘#000‘; 114 this.lineWidth = 1; 115 this.drawType = ‘line‘; 116 this.paintType = ‘stroke‘; 117 this.nums = 6; //正多边形的边数 118 } 119 120 Shape.prototype = { 121 init: function () { 122 this.oGc.fillStyle = this.fillStyle; 123 this.oGc.strokeStyle = this.strokeStyle; 124 this.oGc.lineWidth = this.lineWidth; 125 }, 126 draw: function () { 127 var _this = this; 128 this.oCanvas.onmousedown = function (ev) { 129 _this.init(); 130 var oEvent = ev || event, 131 startX = oEvent.clientX - _this.oCanvas.offsetLeft, 132 startY = oEvent.clientY - _this.oCanvas.offsetTop; 133 _this.oCanvas.onmousemove = function (ev) { 134 _this.oGc.clearRect(0, 0, _this.oCanvas.width, _this.oCanvas.height); 135 var oEvent = ev || event, 136 endX = oEvent.clientX - _this.oCanvas.offsetLeft, 137 endY = oEvent.clientY - _this.oCanvas.offsetTop; 138 _this[_this.drawType](startX, startY, endX, endY); 139 }; 140 _this.oCanvas.onmouseup = function () { 141 _this.oCanvas.onmousemove = null; 142 _this.oCanvas.onmouseup = null; 143 } 144 } 145 }, 146 line: function (x1, y1, x2, y2) { 147 this.oGc.beginPath(); 148 this.oGc.moveTo(x1, y1); 149 this.oGc.lineTo(x2, y2); 150 this.oGc.closePath(); 151 this.oGc.stroke(); 152 }, 153 circle: function (x1, y1, x2, y2) { 154 this.oGc.beginPath(); 155 var r = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)); 156 this.oGc.arc(x1, y1, r, 0, 2 * Math.PI, false); 157 this.oGc.closePath(); 158 this.oGc[this.paintType](); 159 }, 160 rect: function (x1, y1, x2, y2) { 161 this.oGc.beginPath(); 162 this.oGc.rect(x1, y1, x2 - x1, y2 - y1); 163 this.oGc[this.paintType](); 164 }, 165 polygon: function (x1, y1, x2, y2) { 166 var angle = 360 / this.nums * Math.PI / 180;//边对应的角的弧度 167 var r = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)); 168 this.oGc.beginPath(); 169 for (var i = 0; i < this.nums; i++) { 170 this.oGc.lineTo(x1 + r * Math.cos(angle * i), y1 + r * Math.sin(angle * i)); 171 } 172 this.oGc.closePath(); 173 this.oGc[this.paintType](); 174 } 175 } 176 177 var oShape = new Shape(oCanvas, oGc, cWidth, cHeight); 178 function checkPaintType(liType) { 179 var dataType = liType.parentNode.parentNode.dataset.type; 180 var curType = liType.dataset.role; 181 switch (dataType) { 182 case ‘paint-shape‘: //形状 183 oShape.drawType = curType; 184 if (curType == ‘polygon‘) { 185 oShape.nums = prompt("请输入边数", 6); 186 } 187 oShape.draw(); 188 break; 189 case ‘paint-color‘: //绘制颜色 190 liType.children[0].onchange = function () { 191 oShape[this.dataset.role] = this.value; 192 } 193 oShape.draw(); 194 break; 195 case ‘paint-type‘: //绘制类型 196 oShape.paintType = curType; 197 oShape.draw(); 198 break; 199 } 200 } 201 // ]]></script> 202 <style> 203 .paint * { 204 margin: 0; 205 padding: 0; 206 } 207 208 .paint ul, 209 .paint li { 210 list-style: none; 211 } 212 213 .paint li:hover { 214 cursor: pointer; 215 } 216 217 .paint { 218 width: 980px; 219 margin: 20px auto; 220 border: 1px solid #ccc; 221 overflow: hidden; 222 } 223 224 .paint .paint-header ul { 225 width: 980px; 226 height: 40px; 227 line-height: 40px; 228 border-bottom: 1px solid #ccc; 229 } 230 231 .paint .paint-header li { 232 float: left; 233 width: 120px; 234 height: 40px; 235 line-height: 40px; 236 text-align: center; 237 } 238 239 .paint li.active { 240 box-shadow: #666 0px 1px 8px inset; 241 } 242 243 .paint .paint-body .siderbar { 244 float: left; 245 width: 150px; 246 height: 500px; 247 } 248 249 .paint .paint-body .item { 250 width: 150px; 251 overflow: hidden; 252 display: none; 253 height: 500px; 254 border-right: 1px solid #ccc; 255 } 256 257 .paint .paint-body canvas { 258 float: right; 259 } 260 261 .paint .paint-body .item li { 262 height: 40px; 263 text-align: center; 264 border-bottom: 1px solid #ccc; 265 line-height: 40px; 266 } 267 268 .paint .paint-body .active { 269 display: block; 270 } 271 </style> 272 </body> View Code

关于流程设计,后期要做的功能,思路基本上已经有了,好了,圆规正传,想要完成这个终极目标,完成一个画图工具应该就能接近目标了。先体验下目前的简易功能,下面是可以正常画图的,【需要你的浏览器支持canvas才可以额】

  • 形状
  • 颜色
  • 绘制类型
  • 线条宽度
  • 橡皮擦
  • 线条
  • 圆形
  • 矩形
  • 正多边形
  • 箭头
  • 描边
  • 填充
  • 小号
  • 中号
  • 大号

主要来讲下目标的雏形架构:

1,图形绘制部分,我封装了一个类Shape

 1 function Shape(canvasObj, cxtObj, w, h) {
 2         this.oCanvas = canvasObj;
 3         this.oGc = cxtObj;
 4         this.oCanvas.width = w;
 5         this.oCanvas.height = h;
 6         this.fillStyle = ‘#000‘;
 7         this.storkeStyle = ‘#000‘;
 8         this.lineWidth = 1;
 9         this.drawType = ‘line‘;
10         this.paintType = ‘stroke‘;
11         this.nums = 6; //正多边形的边数
12     }

canvasObj: 就是canvas画布对象

cxtObj: 就是上下文绘图环境

w: canvas的宽度

h: canvas的高度

fillStyle: 填充颜色

strokeStyle: 描边颜色

lineWidth: 线宽

drawType: 默认为画直线

paintType: stroke/fill 两种选择( 描边/填充)

2,在原型对象上扩展一个公共方法draw用来绘制图形

draw方法,主要获取起始点坐标(startX, startY),以及终点坐标( endX, endY );

然后调用init方法来获取绘制状态,绘制具体的图形靠下面这个关键方法:

_this[_this.drawType](startX, startY, endX, endY)

这个方法的drawType会根据界面的实时选择,变换对应的绘制类型,如:

_this[‘line‘]( startX, startY, endX, endY )

调用的就是oShape对象中的line,画直线的方法

 1 Shape.prototype = {
 2         init: function () {
 3             this.oGc.fillStyle = this.fillStyle;
 4             this.oGc.strokeStyle = this.strokeStyle;
 5             this.oGc.lineWidth = this.lineWidth;
 6         },
 7         draw: function () {
 8             var _this = this;
 9             this.oCanvas.onmousedown = function ( ev ) {
10                 _this.init();
11                 var oEvent = ev || event,
12                     startX = oEvent.clientX - _this.oCanvas.offsetLeft,
13                     startY = oEvent.clientY - _this.oCanvas.offsetTop;
14                 _this.oCanvas.onmousemove = function ( ev ) {
15                     _this.oGc.clearRect( 0, 0, _this.oCanvas.width, _this.oCanvas.height );
16                     var oEvent = ev || event,
17                         endX = oEvent.clientX - _this.oCanvas.offsetLeft,
18                         endY = oEvent.clientY - _this.oCanvas.offsetTop;
19                     _this[_this.drawType](startX, startY, endX, endY);
20                 };
21                 _this.oCanvas.onmouseup = function(){
22                     _this.oCanvas.onmousemove = null;
23                     _this.oCanvas.onmouseup = null;
24                 }
25             }
26         },
27         line: function ( x1, y1, x2, y2 ) {
28             this.oGc.beginPath();
29             this.oGc.moveTo( x1, y1 );
30             this.oGc.lineTo( x2, y2 );
31             this.oGc.closePath();
32             this.oGc.stroke();
33         },
34         circle : function( x1, y1, x2, y2 ){
35             this.oGc.beginPath();
36             var r = Math.sqrt( Math.pow( x2 - x1, 2 ) + Math.pow( y2 - y1, 2 ) );
37             this.oGc.arc( x1, y1, r, 0, 2 * Math.PI, false );
38             this.oGc.closePath();
39             this.oGc[this.paintType]();
40         },
41         rect : function( x1, y1, x2, y2 ){
42             this.oGc.beginPath();
43             this.oGc.rect( x1, y1, x2 - x1, y2 - y1 );
44             this.oGc[this.paintType]();
45         },
46         polygon : function( x1, y1, x2, y2 ){
47             var angle = 360 / this.nums * Math.PI / 180;//边对应的角的弧度
48             var r = Math.sqrt( Math.pow( x2 - x1, 2 ) + Math.pow( y2 - y1, 2 ) );
49             this.oGc.beginPath();
50             for( var i = 0; i < this.nums; i ++ ){
51                 this.oGc.lineTo( x1 + r * Math.cos( angle * i ), y1 + r * Math.sin( angle * i ) );
52             }
53             this.oGc.closePath();
54             this.oGc[this.paintType]();
55         }
56     }

3,界面操作很简单,基本是选项卡的操作+html5的自定义属性+classList的应用

http://www.bkjia.com/HTML5/1229633.htmlwww.bkjia.comtruehttp://www.bkjia.com/HTML5/1229633.htmlTechArticle[js高手之路]html5 canvas动画教程, 这个绘图工具,我还没有做完,不过已经实现了总架构,以及常见的简易图形绘制功能: 1,可以绘制直线...