https://www.tai-an.tw/js/code.js

1function draw(show_num) {
2    var canvas_width=$('#canvas').width();
3    var canvas_height=$('#canvas').height();
4    var canvas = document.getElementById("canvas");
5    var context = canvas.getContext("2d");
6    canvas.style.backgroundColor='#fff';
7    canvas.width = canvas_width;
8    canvas.height = canvas_height;
9    var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
10    var aCode = sCode.split(",");
11    var aLength = aCode.length;
12
13    for (var i = 0; i <= 3; i++) {
14        var j = Math.floor(Math.random() * aLength);
15        var deg = Math.random() * 30 * Math.PI / 180;
16        var txt = aCode[j];
17        show_num[i] = txt.toLowerCase();
18        var x = 10 + i * 20;
19        var y = 20 + Math.random() * 8;
20        context.font = "bold 23px 新細明體";
21
22        context.translate(x, y);
23        context.rotate(deg);
24
25        context.fillStyle = randomColor();
26        context.fillText(txt, 0, 0);
27
28        context.rotate(-deg);
29        context.translate(-x, -y);
30    }
31//    for (var i = 0; i <= 5; i++) {
32//        context.strokeStyle = randomColor();
33//        context.beginPath();
34//        context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
35//        context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
36//        context.stroke();
37//    }
38    for (var i = 0; i <= 30; i++) {
39        context.strokeStyle = randomColor();
40        context.beginPath();
41        var x = Math.random() * canvas_width;
42        var y = Math.random() * canvas_height;
43        context.moveTo(x, y);
44        context.lineTo(x + 1, y + 1);
45        context.stroke();
46    }
47}
48
49function randomColor() {
50    var r = Math.floor(Math.random() * 128);
51    var g = Math.floor(Math.random() * 128);
52    var b = Math.floor(Math.random() * 128);
53    return "rgb(" + r + "," + g + "," + b + ")";
54}