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本文是项目实战篇 最近项目中需要实现一个教师端设置手势签到密码，学生端绘制正确图案的需求。 这个跟我们手机的设置图案解锁密码是一样的功能。 我们一起看看吧~
如上图要实现这个绘制界面
html代码
html代码很简单，绘制部分的9个圈圈用canvas绘制。
<view class='page'>
<view class='hd d-fx'>
<text class="fs16">手势签到</text>
<text class='main-color fs16' bindtap='reset'>重置手势</text>
</view>
<view class='bd'>
<view class='title'>{{lockMsg}}</view>
<canvas canvas-id="canvas" class="canvas" bindtouchend="onTouchEnd" bindtouchstart="onTouchStart"
bindtouchmove="onTouchMove"></canvas>
</view>
</view>
教师端-绘制图形-绘制2次，绘制图形一致
绘制密码时候，需要绘制2次，判断是否一致。不一致就提示错误
data: {
lockMsg: '请绘制图案',
lockType: 1,
gesture: '', // 绘制图案
},
// 初始化绘制图形
initLocker() {
this.lock = new Locker(this, {
id: 'canvas',
lockType: this.data.lockType,
onSuccess: (e) => {
this.setData({
gesture: e.lockPwd
})
}
});
},
// 重置
reset(e) {
this.lock.reset();
},
学生端-解锁-判断正确与否
// 初始化绘制图形-解锁
initLocker() {
this.lock = new Locker(this, {
id: 'canvas',
lockType: this.data.lockType,
gesture: this.data.detail.gesture,
onSuccess: (e) => {
this.setData({
gesture: e.lockPwd
})
this.isSubmitUseful();
}
});
},
引入lock.js-封装的绘制代码，可以根据实际需求修改
/**
* canvasId: 画布ID, 默认'canvas'
* lockType: 1--setting设置密码, 2--unlock解锁
* width: 图案区域宽度，px
* successColor: 图案设置或解锁成功时,划过的圆周线颜色
* errorColor: 图案设置或解锁失败时,划过的圆周线颜色
* cleColor: 9个圆点的圆周线颜色
* cleCenterColor: 9个原点的中心小点颜色，及连接线颜色
* storageKey: 保存密码的key
* onTouchEnd(e): 触摸结束回调
* onSuccess(e): 密码设置成功、解锁成功回调
*/
var Locker = class {
constructor(page, opt) {
var obj = opt || {};
this.page = page;
this.width = obj.width || 300;
this.height = this.width;
this.canvasId = obj.id || 'canvas';
this.successColor = obj.successColor || '#FB8337'; // 主色橙色
this.errorColor = obj.errorColor || '#e64340';
this.cleColor = obj.cleColor || '#ccc'; // 灰色
this.cleCenterColor = obj.cleCenterColor || '#FB8337'; // 主色橙色
this.lockType = obj.lockType || 1; //1->setting, 2->unlock
this.lockStep = 1;
this.lockMsg = "请绘制图案";
this.gesture = obj.gesture;
this.storageKey = obj.storageKey || 'locker_password';
this.onTouchEnd = obj.onTouchEnd ? obj.onTouchEnd : function (e) {};
this.onSuccess = obj.onSuccess ? obj.onSuccess : function (e) {};
this.init();
}
init() {
// 创建 canvas 绘图上下文（指定 canvasId）
this.ctx = wx.createCanvasContext(this.canvasId, this);
this.touchFlag = false;
this.lastPoint = [];
// 绘制9个点
this.createCircles();
// canvas绑定事件
this.bindEvent();
// 界面文案
this.page.setData({
lockMsg: this.lockMsg
});
// 读取保存的密码
if (this.lockType == 2) {
this.savedPwd = this.gesture;
}
}
// 修改绘制的类型
changeLockType(lockType = 1) {
this.lockType = lockType;
if (this.lockType == 2) { // 读取保存的密码
this.savedPwd = this.gesture;
}
this.reset();
}
// 画圆方法
drawCircle(x, y, color) {
color = color || this.cleCenterColor;
// 设置边框颜色。
this.ctx.setStrokeStyle(color);
// 设置线条的宽度。
this.ctx.setLineWidth(1);
// 开始创建一个路径，需要调用fill或者stroke才会使用路径进行填充或描边。
this.ctx.beginPath();
this.ctx.arc(x, y, this.r, 0, Math.PI * 2, true);
this.ctx.closePath();
// 画出当前路径的边框。默认颜色色为黑色。
this.ctx.stroke();
// 将之前在绘图上下文中的描述（路径、变形、样式）画到 canvas 中。
this.ctx.draw(true);
}
// 创建解锁点的坐标，根据canvas的大小（默认300px）来平均分配半径
createCircles() {
var n = 3,
count = 0;
// 计算圆半径
this.r = this.width / ((2 * n + 1) * 2);
this.arr = [];
this.restPoint = [];
var r = this.r;
// 获取圆心坐标，以及当前圆所代表的数
for (var i = 0; i < n; i++) {
for (var j = 0; j < n; j++) {
count++;
var obj = {
x: j * 4 * r + 3 * r,
y: i * 4 * r + 3 * r,
index: count
};
this.arr.push(obj);
this.restPoint.push(obj);
}
}
// 清空画布
this.ctx.clearRect(0, 0, this.width, this.height);
// 绘制所有的圆
this.arr.forEach(current => {
this.drawCircle(current.x, current.y, this.cleColor);
});
}
// 获取touch点相对于canvas的坐标
getPosition(e) {
return {
x: e.touches[0].x,
y: e.touches[0].y
};
}
// 绘制触摸点
drawPoint(x, y, color) {
color = color || this.cleCenterColor;
this.ctx.setFillStyle(color); // 注意用set方法
this.ctx.beginPath();
this.ctx.arc(x, y, this.r / 2, 0, Math.PI * 2, true);
this.ctx.closePath();
this.ctx.fill();
this.ctx.draw(true);
}
// 初始化状态线条
drawStatusPoint(color) {
for (var i = 0; i < this.lastPoint.length; i++) {
this.drawCircle(this.lastPoint[i].x, this.lastPoint[i].y, color);
}
}
// 绘制线路
drawLine(po1, po2) {
this.ctx.beginPath();
this.ctx.lineWidth = 2;
this.ctx.setStrokeStyle(this.successColor); // add
this.ctx.moveTo(po1.x, po1.y);
this.ctx.lineTo(po2.x, po2.y);
this.ctx.stroke();
this.ctx.closePath();
this.ctx.draw(true);
}
// 如果po在剩余可用点的圆内，则画触摸点和轨迹线
drawTrace(po) {
for (var i = 0; i < this.restPoint.length; i++) {
var pt = this.restPoint[i];
if (Math.abs(po.x - pt.x) < this.r && Math.abs(po.y - pt.y) < this.r) {
this.drawPoint(pt.x, pt.y);
this.drawLine(this.lastPoint[this.lastPoint.length - 1], pt);
this.lastPoint.push(pt);
this.restPoint.splice(i, 1);
break;
}
}
}
// 重置线路
reset() {
this.lockStep = 1, this.lastPoint = [], this.lockMsg = "请绘制图案";
// 绘制圆
this.createCircles();
//
this.page.setData({
lockMsg: this.lockMsg
});
}
// 获取图形密码
getLockPwd() {
var str = "";
for (var i = 0; i < this.lastPoint.length; i++) {
str += this.lastPoint[i].index + "";
}
return str;
}
// 绘制结束
bindEvent() {
var self = this;
this.page.onTouchStart = function (e) {
// console.log("t: ", self.lastPoint);
if (self.lastPoint.length > 0) return; // 上次绘制没有清理干净
var po = self.getPosition(e);
for (var i = 0; i < self.arr.length; i++) {
// 坐标是否在圆内？
if (Math.abs(po.x - self.arr[i].x) < self.r && Math.abs(po.y - self.arr[i].y) < self.r) {
self.touchFlag = true;
self.drawPoint(self.arr[i].x, self.arr[i].y);
self.lastPoint.push(self.arr[i]);
self.restPoint.splice(i, 1);
break;
}
}
}
this.page.onTouchMove = function (e) {
if (self.touchFlag) {
self.drawTrace(self.getPosition(e));
}
}
this.page.onTouchEnd = function (e) {
let success = false;
if (self.touchFlag) {
self.touchFlag = false;
e.lockType = self.lockType;
e.lockStep = self.lockStep;
e.lockPwd = self.getLockPwd();
self.onTouchEnd(e);
if (self.lockType == "1") { // setting pwd
if (self.lockStep == 1) {
if (e.lockPwd.length < 4) {
self.lockMsg = "至少绘制4个及以上点";
} else {
self.lockMsg = "请再次绘制图案";
self.lockPwd = e.lockPwd, self.lockStep++;
}
} else {
if (e.lockPwd == self.lockPwd) {
self.lockMsg = "图案绘制成功";
self.drawStatusPoint(self.successColor);
// 绘制完成存密码
success = true;
} else {
self.drawStatusPoint(self.errorColor);
self.lockMsg = "两次不一致，请重新绘制";
}
}
} else { // unlock pwd
if (e.lockPwd == self.savedPwd) {
self.lockMsg = "图案绘制成功";
self.drawStatusPoint(self.successColor);
success = true;
} else {
self.drawStatusPoint(self.errorColor);
self.lockMsg = "图案错误, 请重新绘制";
}
}
self.page.setData({
lockMsg: self.lockMsg
});
if (success) {
self.lockMsg = "图案绘制成功";
self.onSuccess(e);
} else {
setTimeout(function () {
self.lastPoint = [], self.createCircles();
if (success) {
self.onSuccess(e);
}
}, 1000);
}
}
}
}
}
module.exports = Locker;
