html5 canvas+js实现ps钢笔抠图

  1  <script type="text/javascript">
  2         $(function () {
  3             var a = new tailorImg();
  4             a.iniData();
  5         });
  6         //
  7         var tailorImg=function()
  8         {
  9             this.iniData = function () {
 10                 //画布
 11                 this.can.id = "canvas";
 12                 this.can.w = 400;
 13                 this.can.h = 400;
 14                 this.can.roundr = 7;
 15                 this.can.roundrr = 3;
 16                 this.can.curPointIndex = 0;
 17                 this.can.imgBack.src = "gzf.png";
 18                 this.can.canvas = document.getElementById(this.can.id).getContext("2d");
 19                 //图片
 20                 this.img.w = 400;
 21                 this.img.h = 400;
 22                 this.img.image.src = "flower.jpg";
 23                 //加载事件：
 24                 //初始化事件：
 25                 var a = this;
 26                 var p = a.can.pointList;
 27                 $("#" + a.can.id).mousemove(function (e) {
 28                     if (a.can.paint) {//是不是按下了鼠标  
 29                         if (p.length > 0) {
 30                             a.equalStartPoint(p[p.length - 1].pointx, p[p.length - 1].pointy);
 31                         }
 32                         a.roundIn(e.offsetX, e.offsetY);
 33                     }
 34                     //判断是否在直线上
 35                     //光标移动到线的附近如果是闭合的需要重新划线，并画上新添加的点
 36                     a.AddNewNode(e.offsetX, e.offsetY);
 37                 });
 38                 $("#" + a.can.id).mousedown(function (e) {
 39                     a.can.paint = true;
 40                     //点击判断是否需要在线上插入新的节点：
 41                     if (a.can.tempPointList.length > 0) {
 42                         a.can.pointList.splice(a.can.tempPointList[1].pointx, 0, new a.point(a.can.tempPointList[0].pointx, a.can.tempPointList[0].pointy));
 43                         //清空临时数组
 44                         a.can.tempPointList.length = 0;
 45                     }
 46                 });
 47                 $("#" + a.can.id).mouseup(function (e) {
 48                     //拖动结束
 49                     a.can.paint = false;
 50                     //拖动结束；
 51                     if (a.can.juPull) {
 52                         a.can.juPull = false;
 53                         a.can.curPointIndex = 0;
 54                         //验证抠图是否闭合：闭合，让结束点=开始点；添加标记
 55                         a.equalStartPoint(p[p.length - 1].pointx, p[p.length - 1].pointy);
 56                         //判断是否闭合：
 57                         if (a.can.IsClose) {
 58 
 59                         }
 60                     }
 61                     else {
 62                         //如果闭合：禁止添加新的点；
 63                         if (!a.can.IsClose) {//没有闭合
 64                             p.push(new a.point(e.offsetX, e.offsetY));
 65                             //验证抠图是否闭合：闭合，让结束点=开始点；添加标记
 66                             a.equalStartPoint(p[p.length - 1].pointx, p[p.length - 1].pointy);
 67                             //判断是否闭合：
 68                             //重新画；
 69                             if (p.length > 1) {
 70                                 a.drawLine(p[p.length - 2].pointx, p[p.length - 2].pointy, p[p.length - 1].pointx, p[p.length - 1].pointy);
 71                                 a.drawArc(p[p.length - 1].pointx, p[p.length - 1].pointy);
 72                             } else {
 73                                 a.drawArc(p[p.length - 1].pointx, p[p.length - 1].pointy);
 74                             }
 75                         }
 76                         else {
 77                             //闭合
 78                         }
 79                     }
 80                     //验证是否填充背景：
 81                     if (a.can.IsClose) {
 82                         a.fillBackColor();
 83                         a.drawAllLine();
 84                     }
 85                 });
 86                 $("#" + a.can.id).mouseleave(function (e) {
 87                     a.can.paint = false;
 88                 });
 89                 //鼠标点击事件：
 90                 $("#" + a.can.id).click(function (e) {
 91                     //空
 92                 });
 93             }
 94             this.point = function (x, y) {
 95                 this.pointx = x;
 96                 this.pointy = y;
 97             };
 98             //图片
 99             this.img = {
100                 image:new Image(),
101                 id: "",
102                 w:0,
103                 h:0
104             };
105             //画布；
106             this.can = {
107                 canvas:new Object(),
108                 id: "",
109                 w: 0,
110                 h: 0,
111                 //坐标点集合
112                 pointList: new Array(),
113                 //临时存储坐标点
114                 tempPointList: new Array(),
115                 //圆点的触发半径：
116                 roundr: 7,
117                 //圆点的显示半径：
118                 roundrr: 7,
119                 //当前拖动点的索引值；
120                 curPointIndex : 0,
121                 //判断是否点击拖动
122                 paint : false,
123                 //判断是否点圆点拖动，并瞬间离开,是否拖动点；
124                 juPull : false,
125                 //判断是否闭合
126                 IsClose: false,
127                 imgBack: new Image()
128                 
129             };
130             //函数：
131             //更新画线
132             this.drawAllLine=function () {
133                 for (var i = 0; i < this.can.pointList.length - 1; i++) {
134                     //画线
135                     var p = this.can.pointList;
136                     this.drawLine(p[i].pointx, p[i].pointy, p[i + 1].pointx, p[i + 1].pointy);
137                     //画圈
138                     this.drawArc(p[i].pointx, p[i].pointy);
139                     if (i == this.can.pointList.length - 2) {
140                         this.drawArc(p[i+1].pointx, p[i+1].pointy);
141                     }
142                 }
143             }
144             //画线
145             this.drawLine = function (startX, startY, endX, endY) {
146                 //var grd = this.can.canvas.createLinearGradient(0, 0,2,0); //坐标，长宽
147                 //grd.addColorStop(0, "black"); //起点颜色
148                 //grd.addColorStop(1, "white");
149                 //this.can.canvas.strokeStyle = grd;
150                 this.can.canvas.strokeStyle = "blue"
151                 this.can.canvas.lineWidth =1;
152                 this.can.canvas.moveTo(startX, startY);
153                 this.can.canvas.lineTo(endX, endY);
154                 this.can.canvas.stroke();
155             }
156             //画圈：
157             this.drawArc=function(x, y) {
158                this.can.canvas.fillStyle = "blue";
159                 this.can.canvas.beginPath();
160                 this.can.canvas.arc(x, y,this.can.roundrr, 360, Math.PI * 2, true);
161                 this.can.canvas.closePath();
162                 this.can.canvas.fill();
163             }
164             //光标移到线上画大圈：
165             this.drawArcBig = function (x, y) {
166                 this.can.canvas.fillStyle = "blue";
167                 this.can.canvas.beginPath();
168                 this.can.canvas.arc(x, y, this.can.roundr+2, 360, Math.PI * 2, true);
169                 this.can.canvas.closePath();
170                 this.can.canvas.fill();
171             }
172             //渲染图片往画布上
173             this.showImg=function() {
174                 this.img.image.onload = function () {
175                     this.can.canvas.drawImage(this.img.image, 0, 0, this.img.w,this.img.h);
176                 };
177             }
178             //填充背景色
179             this.fillBackColor = function () {
180                 for (var i = 0; i <this.img.w; i += 96) {
181                     for (var j = 0; j <= this.img.h; j += 96) {
182                         this.can.canvas.drawImage(this.can.imgBack, i, j, 96, 96);
183                     }
184                 }
185                 this.can.canvas.globalCompositeOperation = "destination-out";
186                 this.can.canvas.beginPath();
187                 for (var i = 0; i <this.can.pointList.length; i++) {
188                     this.can.canvas.lineTo(this.can.pointList[i].pointx,this.can.pointList[i].pointy);
189                 }
190                 this.can.canvas.closePath();
191                 this.can.canvas.fill();
192                 this.can.canvas.globalCompositeOperation = "destination-over";
193                 this.drawAllLine();
194             }
195             //去掉pointlist最后一个坐标点：
196             this.clearLastPoint=function () {
197                 this.can.pointList.pop();
198                 //重画：
199                 this.clearCan();
200                 this.drawAllLine();
201             }
202             //判断结束点是否与起始点重合；
203             this.equalStartPoint = function (x,y) {
204                 var p = this.can.pointList;
205                 if (p.length > 1 && Math.abs((x - p[0].pointx) * (x - p[0].pointx)) + Math.abs((y - p[0].pointy) * (y - p[0].pointy)) <= this.can.roundr * this.can.roundr) {
206                     //如果闭合
207                     this.can.IsClose = true;
208                     p[p.length - 1].pointx = p[0].pointx;
209                     p[p.length - 1].pointy = p[0].pointy;
210                 }
211                 else {
212                     this.can.IsClose = false;
213                 }
214             }
215             //清空画布
216             this.clearCan=function (){
217                 this.can.canvas.clearRect(0, 0, this.can.w, this.can.h);
218             }
219             //剪切区域
220             this.CreateClipArea=function () {
221                 this.showImg();
222                 this.can.canvas.beginPath();
223                 for (var i = 0; i <this.can.pointList.length; i++) {
224                     this.can.canvas.lineTo(this.can.pointList[i].pointx,this.can.pointList[i].pointy);
225                 }
226                 this.can.canvas.closePath();
227                 this.can.canvas.clip();
228             }
229             //
230             this.CreateClipImg=function()
231             {
232 
233             }
234             //判断鼠标点是不是在圆的内部：
235             this.roundIn = function (x, y) {
236                 //刚开始拖动
237                 var p = this.can.pointList;
238                 if (!this.can.juPull) {
239                     for (var i = 0; i < p.length; i++) {
240 
241                         if (Math.abs((x - p[i].pointx) * (x - p[i].pointx)) + Math.abs((y - p[i].pointy) * (y - p[i].pointy)) <= this.can.roundr * this.can.roundr) {
242                             //说明点击圆点拖动了；
243                             this.can.juPull = true;//拖动
244                             //
245                             this.can.curPointIndex = i;
246                             p[i].pointx = x;
247                             p[i].pointy = y;
248                             //重画：
249                             this.clearCan();
250                             //showImg();
251                             if (this.can.IsClose) {
252                                 this.fillBackColor();
253                             }
254                             this.drawAllLine();
255                             return;
256                         }
257                     }
258                 }
259                 else {//拖动中
260                     p[this.can.curPointIndex].pointx = x;
261                     p[this.can.curPointIndex].pointy = y;
262                     //重画：
263                     this.clearCan();
264                     if (this.can.IsClose) {
265                         this.fillBackColor();
266                     }
267                     this.drawAllLine();
268                 }
269             };
270 
271             //光标移到线上，临时数组添加新的节点：
272            this.AddNewNode=function(newx, newy) {
273                //如果闭合
274                var ii=0;
275                 if (this.can.IsClose) {
276                     //判断光标点是否在线上：
277                     var p = this.can.pointList;
278                     for (var i = 0; i < p.length - 1; i++) {
279                         //计算a点和b点的斜率
280                         var k = (p[i + 1].pointy - p[i].pointy) / (p[i + 1].pointx - p[i].pointx);
281                         var b = p[i].pointy - k * p[i].pointx;
282                         //if (parseInt((p[i + 1].pointy - p[i].pointy) / (p[i + 1].pointx - p[i].pointx)) ==parseInt((p[i + 1].pointy - newy) / (p[i + 1].pointx - newx)) && newx*2-p[i+1].pointx-p[i].pointx<0 && newy*2-p[i+1].pointy-p[i].pointy<0) {
283                         //    //如果在直线上
284                         //    alert("在直线上");
285                         //}
286                         $("#txtone").val(parseInt(k * newx + b));
287                         $("#txttwo").val(parseInt(newy));
288                         if (parseInt(k * newx + b) == parseInt(newy) && (newx - p[i + 1].pointx) * (newx - p[i].pointx) <= 2 && (newy - p[i + 1].pointy) * (newy - p[i].pointy) <= 2) {
289                             //
290                             //parseInt(k * newx + b) == parseInt(newy)
291                             //添加临时点：
292                             this.can.tempPointList[0] = new this.point(newx, newy);//新的坐标点
293                             this.can.tempPointList[1] = new this.point(i+1, i+1);//需要往pointlist中插入新点的索引；
294                             i++;
295                             //alert();
296                             //光标移动到线的附近如果是闭合的需要重新划线，并画上新添加的点；
297                             if (this.can.tempPointList.length > 0) {
298                                 //重画：
299                                 this.clearCan();
300                                 //showImg();
301                                 if (this.can.IsClose) {
302                                     this.fillBackColor();
303                                 }
304                                 this.drawAllLine();
305                                 this.drawArcBig(this.can.tempPointList[0].pointx, this.can.tempPointList[0].pointy);
306                                 return;
307                             }
308                             return;
309                         }
310                         else {
311                            // $("#Text1").val("");
312                         }
313                     }
314                     if (ii == 0) {
315                         if (this.can.tempPointList.length > 0) {
316                             //清空临时数组；
317                             this.can.tempPointList.length = 0;
318                             //重画：
319                             this.clearCan();
320                             //showImg();
321                             if (this.can.IsClose) {
322                                 this.fillBackColor();
323                             }
324                             this.drawAllLine();
325                             //this.drawArc(this.can.tempPointList[0].pointx, this.can.tempPointList[0].pointy);
326                         }
327                     }
328                 }
329                 else {
330                     //防止计算误差引起的添加点，当闭合后，瞬间移动起始点，可能会插入一个点到临时数组，当再次执行时，
331                     //就会在非闭合情况下插入该点，所以，时刻监视：
332                     if (this.can.tempPointList.length > 0) {
333                         this.can.tempPointList.length = 0;
334                     }
335                 }
336            }
337             
338         };
339 
340     </script>

 1  <style type="text/css">
 2         .canvasDiv {
 3             position: relative;
 4             border: 1px solid red;
 5             height: 400px;
 6             width: 400px;
 7             top: 50px;
 8             left: 100px;
 9             z-index: 0;
10         }
11 
12         img {
13             width: 400px;
14             height: 400px;
15             z-index: 1;
16             position: absolute;
17         }
18 
19         #canvas {
20             position: absolute;
21             border: 1px solid green;
22             z-index: 2;
23         }
24         .btnCollection {
25             margin-left: 100px;
26         }
27     </style>

1  <div class="canvasDiv">
2             <img src="flower.jpg" />
3             <canvas id="canvas" width="400" height="400" style="border: 1px solid green;"></canvas>
4         </div>