JavaScript 手势解锁
【摘要】
<!DOCTYPE html>
<html>
<head>
<meta charset="utf8">
<style>
* {
margi...
<!DOCTYPE html>
<html>
<head>
<meta charset="utf8">
<style>
* {
margin: 0;
padding: 0;
}
#canvas {
width: 100%;
height: 100%;
/*! 要想让元素铺满全屏，要么用absolute的100%，要么用100vh */
position: absolute;
}
</style>
<script>
class GestureUnlock {
constructor(canvas) {
//圆圈直径/画布比例
this.circleSizeRatio = 0.1;
//圆圈内部镂空直径/圆圈半径
this.circleHollowRatio = 0.5;
//圆圈边框线宽/圆圈半径
this.circleLineWidthRatio = 0.1;
//画笔线宽/圆圈内部镂空半径
this.lineWidthRatio = 1;
//线条颜色
this.color = "RoyalBlue";
//行数
this.numRow = 3;
//列数
this.numColumn = 5;
//圆圈的坐标数组(x,y)
this.pointPos = [];
//已经选中的圈编号(i)，规则：先横后竖。保存手势的时候只要保存该变量即可
this.points = [];
//起始按下是否在某个圆圈的范围
this.isDownOnPoint = false;
this.doublePI = 2*Math.PI;
this.canvas = canvas;
this.initListener();
this.setData();
this.draw();
}
setData() {
//必须要设置canvas的宽高，而不能用style的宽高，否则默认会按300×150缩放
//注意：当canvas的大小改变时，ctx就会重置，包括之前设置的样式会全部被重置
this.canvas.width = this.canvas.clientWidth;
this.canvas.height = this.canvas.clientHeight;
const size = Math.min(this.canvas.clientWidth, this.canvas.clientHeight);
//圆圈的直径
const circleWidth = size * this.circleSizeRatio;
this.circleR = circleWidth/2;
//连接线可填充的孔洞半径
this.circleHollowR = this.circleR * this.circleHollowRatio;
//圆圈外径和中间可填充的孔洞中间的半径
this.circleMiddleR = (this.circleR + this.circleHollowR) / 2;
//圆圈的边框线条宽度
this.circleLineWidth = this.circleR * this.circleLineWidthRatio;
//圆圈填充白色的宽度
this.circlePadWidth = this.circleR - this.circleHollowR;
//连接线宽度
this.lineWidth = this.circleHollowR * this.lineWidthRatio;
//行的一个间隔长度
this.rowPad = this.canvas.clientHeight/(this.numRow*2);
//列的一个间隔长度
this.columnPad = this.canvas.clientWidth/(this.numColumn*2);
//console.log(this.rowPad, this.columnPad, this.circleR);
this.ctx = canvas.getContext("2d");
this.ctx.strokeStyle = "RoyalBlue";
this.ctx.fillStyle = this.color;
//线条两端的笔帽(lineCap)支持butt(默认)、round、square，但是默认的拐点会突出
this.ctx.lineCap = "round";
//两条线条交汇处的样式(lineJoin)支持miter(默认，尖角)、round、bevel(斜角或缺角)
this.ctx.lineJoin = "bevel"
}
drawCircle() {
this.pointPos = [];
for(let i=0;i<this.numRow;i++) {
for(let j=0;j<this.numColumn;j++) {
const x = (2*j+1)*this.columnPad;
const y = (2*i+1)*this.rowPad;
this.pointPos.push([x, y]);
//console.log(x, y)
this.ctx.beginPath();
this.ctx.strokeStyle = "white";
this.ctx.lineWidth = this.circlePadWidth;
this.ctx.arc(x, y, this.circleMiddleR, 0, this.doublePI);
this.ctx.stroke();
this.ctx.beginPath();
this.ctx.strokeStyle = this.color;
this.ctx.lineWidth = this.circleLineWidth;
this.ctx.arc(x, y, this.circleR, 0, this.doublePI);
this.ctx.stroke();
}
}
}
drawLine(x, y) {
const that = this;
function getPointPos(i) {
return that.pointPos[that.points[i]];
}
if(this.points.length == 0) return;
for(let i=0;i<this.points.length;i++) {
//ES6的自动拆包
this.ctx.beginPath();
this.ctx.arc(...getPointPos(i), this.circleHollowR, 0, this.doublePI);
this.ctx.fill();
}
this.ctx.beginPath();
this.ctx.lineWidth = this.lineWidth;
//ES6的自动拆包
this.ctx.moveTo(...getPointPos(0));
for(let i=1;i<this.points.length;i++) {
this.ctx.lineTo(...getPointPos(i));
}
if(x != undefined && y != undefined) {
this.ctx.lineTo(x, y);
}
this.ctx.stroke();
}
draw(x, y) {
this.ctx.clearRect(0,0,this.canvas.width, this.canvas.height);
this.drawLine(x, y);
this.drawCircle();
}
indexOfPoint(x,y) {
if(this.pointPos.length == 0) throw new Error("未找到圆圈坐标数组");
//为了减少计算量，将每个圆当作正方形来看
for(let i=0;i<this.pointPos.length;i++) {
if((Math.abs(x - this.pointPos[i][0]) < this.circleR) &&
(Math.abs(y - this.pointPos[i][1]) < this.circleR)) {
return i;
}
}
return -1;
}
pushToPoints(index) {
if(index == -1 || this.points.includes(index)) return false;
this.points.push(index);
return true;
}
initListener() {
//内嵌箭头函数(即匿名函数)是为了继续使用this
this.canvas.addEventListener("mousedown", (e)=>{this.touchStart(e);});
this.canvas.addEventListener("mousemove", (e)=>{this.touchMove(e);});
this.canvas.addEventListener("mouseup", (e)=>{this.touchEnd(e);});
this.canvas.addEventListener("touchstart", (e)=>{this.touchStart(e);});
this.canvas.addEventListener("touchmove", (e)=>{this.touchMove(e);});
this.canvas.addEventListener("touchend", (e)=>{this.touchEnd(e);});
window.addEventListener("resize", ()=>{ this.setData(); this.draw(); });
}
//兼容PC端和手机端的获取单击点坐标
getEventPos(event) {
const x = event.clientX || event.touches[0].clientX;
const y = event.clientY || event.touches[0].clientY;
return [x,y];
}
touchStart(e) {
const [x,y] = this.getEventPos(e);
this.points = [];
const index = this.indexOfPoint(x, y);
this.isDownOnPoint = this.pushToPoints(index);
}
touchMove(e) {
if(!this.isDownOnPoint) return;
const [x,y] = this.getEventPos(e);
const index = this.indexOfPoint(x, y);
this.pushToPoints(index);
this.draw(x, y);
}
touchEnd(e) {
if(!this.isDownOnPoint) return;
this.isDownOnPoint = false;
this.draw();
if(this.points.length > 1) {
/*
浏览器中弹出的对话框都是模态对话框（Modal Dialogue Box，又叫做模式对话框）
是指在用户想要对对话框以外的应用程序进行操作时，必须首先对该对话框进行响应。
*/
//conform 遵守；confirm 确认
//const ret = confirm("点击的顺序是：" + this.points.join(" -> "));
alert("点击的顺序是：" + this.points.join(" -> "));
this.points = [];
this.draw();
}
}
}
window.()=>{
const canvas = document.getElementById("canvas");
const gestureUnlock = new GestureUnlock(canvas);
}
</script>
</head>
<body>
<canvas id="canvas"></canvas>
</body>
</html>
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文章来源: blog.csdn.net，作者：福州-司马懿，版权归原作者所有，如需转载，请联系作者。
原文链接：blog.csdn.net/chy555chy/article/details/86552453
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