1 function SpritCtx(img, size, pos, turnTime, totalCount, ctx) {
2 size = size || {};
3 pos = pos || {};
4 //img
5 this.img = img;
6 //size
7 this.width = size.width || 5;
8 this.height = size.height || 5;
9 //pos
10 this.left = pos.left || 0; //画布上的位置left
11 this.top = pos.top || 0; //画布上的位置top
12 //初始化cellNum,count,cell,row
13 this.cellNum = 1;
14 var that = this;
15 this.img.onload = function() {
16 that.cellNum = Math.floor(that.img.width / that.width); //每行的个数
17 }
18 this.count = 0; //显示第几个
19 this.cell = 0;
20 this.row = 0;
21 //定时器时间
22 this.turnTime = turnTime || 90;
23 //图片数量
24 this.totalCount = totalCount;
25 //canvas
26 this.ctx = ctx;
27 //定时器
28 this.xTimer = null;
29 }
30
31 SpritCtx.prototype.draw = function() {
32 this.ctx.drawImage(
33 this.img,
34 this.width * this.cell,
35 this.height * this.row,
36 this.width,
37 this.height,
38 this.left,
39 this.top,
40 this.width,
41 this.height
42 );
43 return this;
44 };
45
46 SpritCtx.prototype.start = function() {
47 var that = this;
48 clearInterval(this.xTimer);
49 this.xTimer = setInterval(function () {
50 that.timerFn();
51 }, this.turnTime);
52 return this;
53 };
54
55 SpritCtx.prototype.stop = function() {
56 clearInterval(this.xTimer);
57 return this;
58 };
59
60 SpritCtx.prototype.timerFn = function() {
61 this.count++;
62 this.count %= this.totalCount;
63 this.row = Math.floor(this.count / this.cellNum); //第几行
64 this.cell = this.count - this.row * this.cellNum; //第几列
65 return this;
66 };
67
68 SpritCtx.prototype.turnPos = function(left, top) {
69 this.left = left || 0;
70 this.top = top || 0;
71 return this;
72 };
