let nums = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0",
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
];
let str = ref('');
let verVal
export const VerifyCode = (width:number,height:number) => {
// 绘制验证码
function drawCode() {
const canvas = document.createElement('canvas') as HTMLCanvasElement //创建画布
var context = canvas.getContext("2d"); //canvas的画布2D上下文
context!.fillStyle = "cornflowerblue"; //画布背景填充色
context!.fillRect(0, 0, width, height); //设置画布坐标,大小
context!.fillStyle = "white"; //设置字体颜色
context!.font = "25px Arial"; //设置字体
var rand = new Array();
var x = new Array();
var y = new Array();
//生成4位随机数
for (var i = 0; i < 4; i++) {
rand[i] = nums[Math.floor(Math.random() * nums.length)] //从字符集中随机取一位
x[i] = i * 20 + 10; //开始绘制文本的x坐标(相对于画布)
y[i] = Math.random() * 20 + 20;
context!.fillText(rand[i], x[i], y[i]); //写入文本
}
str.value = rand.join('').toUpperCase(); //验证码字符串
//画3条随机线
for (var i = 0; i < 3; i++) {
drawline(canvas, context);
}
// 画30个随机点
for (var i = 0; i < 30; i++) {
drawDot(canvas, context);
}
return reactive({
str, //验证码字符串
url: canvas.toDataURL("image/png") //画布图片路径
})
}
// 生成随机线
function drawline(canvas, context) {
context.moveTo(Math.floor(Math.random() * width), Math.floor(Math.random() * height)); //随机线的起点x坐标是画布x坐标0位置,y坐标是画布高度的随机数
context.lineTo(Math.floor(Math.random() * width), Math.floor(Math.random() * height)); //随机线的终点x坐标是画布宽度,y坐标是画布高度的随机数
context.lineWidth = Math.random(); //随机线宽
context.strokeStyle = 'rgba(50,50,50,0.3)'; //随机线描边属性
context.stroke(); //描边,即起点描到终点
}
// 生成随机点(所谓画点其实就是画1px像素的线)
function drawDot(canvas, context) {
var px = Math.floor(Math.random() * width);
var py = Math.floor(Math.random() * height);
context.moveTo(px, py);
context.lineTo(px + 1, py + 1);
context.lineWidth = 0.2;
context.stroke();
}
verVal = drawCode();
return verVal //将生成的str 和 url 返回
}