HTML5 Canvas 画纸飞机组件

纸飞机模拟一个物体在规定设计轴线偏离方位。

 1 //三角形
 2 function DrawTriangle(canvas, A, B, C) {
 3     //画个三角形,“A、B、C”是顶点
 4     with (canvas) {
 5         moveTo(A[0], A[1]);
 6         lineTo(B[0], B[1]);
 7         lineTo(C[0], C[1]);
 8         lineTo(A[0], A[1]);
 9     }
10 }
11 
12 // 画纸飞机
13 //headx,heady 纸飞机头坐标
14 //footx,footy 纸飞机尾巴坐标
15 function DrawDarts(canvas, headx, heady, footx, footy) {
16     var c = document.getElementById(canvas);
17     var cxt = c.getContext("2d");
18 
19     //半径 R 
20     var R = 150;
21 
22     //转换头坐标
23     var headx1 = R + headx;
24     var heady1 = R - heady;
25     //转换尾坐标
26     var footx1 = R + footx;
27     var footy1 = R - footy;
28 
29     //左尾
30     var footxl = R + (footx - 50);
31     var footyl = R - footy;
32 
33     //右尾
34     var footxr = R + (footx + 50);
35     var footyr = R - footy;
36 
37     //上尾
38     var footxu = R + footx;
39     var footyu = R - (footy - 50);
40 
41     //下尾
42     var footxd = R + footx;
43     var footyd = R - (footy + 50);
44 
45 
46     //判断头x和尾x的大小
47     cxt.beginPath();
48     cxt.strokeStyle = "black";
49     cxt.fillStyle = "#6C8D9F";
50     var A = new Array(headx1, heady1);
51     var B = new Array(footx1, footy1);
52     //  alert(headx1);
53     //  alert(footx1);
54     if (parseInt(headx1) - parseInt(footx1) <= 0)
55         var C = new Array(footxr, footyr);
56     else
57         var C = new Array(footxl, footyl);
58     DrawTriangle(cxt, A, B, C);
59 
60     cxt.fill();
61     cxt.closePath();
62     cxt.stroke();
63 
64     //画头、上、下尾巴 形成的三角形
65     cxt.beginPath();
66     cxt.strokeStyle = "black";
67     cxt.fillStyle = "#6C8D9F";
68     var A1 = new Array(headx1, heady1);
69     var B1 = new Array(footxu, footyu);
70     var C1 = new Array(footxd, footyd);
71     DrawTriangle(cxt, A1, B1, C1);
72     cxt.fill();
73     cxt.closePath();
74     cxt.stroke();
75 
76     cxt.beginPath();
77     cxt.strokeStyle = "black";
78     cxt.fillStyle = "#6C8D9F";
79     var A2 = new Array(headx1, heady1);
80     var B2 = new Array(footx1, footy1);
81     if (parseInt(headx1) - parseInt(footx1) <= 0)
82         var C2 = new Array(footxl, footyl);
83     else
84         var C2 = new Array(footxr, footyr);
85     DrawTriangle(cxt, A2, B2, C2);
86     cxt.fill();
87     cxt.closePath();
88     cxt.stroke();
89 }

html 页面调用

<!DOCTYPE HTML>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>HTML Canvas 画纸飞机</title>
<script type="text/javascript" src="Darts.js"></script>
</head>
<body><canvas id="can" width="300" height="300" style="border: 1px solid #00F">浏览器不支持HTML5！</canvas><script type="text/javascript" charset="utf-8">DrawDarts("can", -10, 10, 30, -30)</script>
</body>
</html>