本文实例为大家分享了微信小程序实现图形验证码的具体代码，供大家参考，具体内容如下
1.wxml页面
<canvas canvas-id="canvas" bindtap='change' style="width:90px;height: 30px;"></canvas>2.js页面
var app = getApp();
var baseUrl = getApp().baseUrl;
var ctx;
data:{
text:""
},
onLoad: function(options) {
var that = this;
this.drawPic(that);
},
change: function() {
var that = this;
this.drawPic(that);
},
mobile(e) {
this.setData({
mobile: e.detail.value
})
},
randomNum(min, max) {
return Math.floor(Math.random() * (max - min) + min);
},
randomColor(min, max) {
let r = this.randomNum(min, max);
let g = this.randomNum(min, max);
let b = this.randomNum(min, max);
return "rgb(" + r + "," + g + "," + b + ")";
},
drawPic(that) {
ctx = wx.createCanvasContext('canvas');
ctx.fillStyle = this.randomColor(180, 240); //颜色若太深可能导致看不清
ctx.fillRect(0, 0, 90, 28)
var arr;
var text = '';
var str = 'ABCEFGHJKLMNPQRSTWXY123456789';
for (var i = 0; i < 4; i++) {
var txt = str[this.randomNum(0, str.length)];
ctx.fillStyle = this.randomColor(50, 160); //随机生成字体颜色
ctx.font = this.randomNum(20, 26) + 'px SimHei'; //随机生成字体大小
var x = 5 + i * 20;
var y = this.randomNum(20, 25);
var deg = this.randomNum(-20, 20);
//修改坐标原点和旋转角度
ctx.translate(x, y);
ctx.rotate(deg * Math.PI / 180);
ctx.fillText(txt, 5, 0);
text = text + txt;
//恢复坐标原点和旋转角度
ctx.rotate(-deg * Math.PI / 180);
ctx.translate(-x, -y);
}
for (var i = 0; i < 4; i++) {
ctx.strokeStyle = this.randomColor(40, 180);
ctx.beginPath();
ctx.moveTo(this.randomNum(0, 90), this.randomNum(0, 28));
ctx.lineTo(this.randomNum(0, 90), this.randomNum(0, 28));
ctx.stroke();
}
for (var i = 0; i < 20; i++) {
ctx.fillStyle = this.randomColor(0, 255);
ctx.beginPath();
ctx.arc(this.randomNum(0, 90), this.randomNum(0, 28), 1, 0, 2 * Math.PI);
ctx.fill();
}
ctx.draw(false, function() {
that.setData({
text: text
})
});3.效果
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持编程网。
