需要获取鼠标的移动角度
1、mousedown 确定起始点
2、mousemove 确立相关点
3、先计算两点的斜率，然后根据三角函数和反三角函数。转换为角度
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
.circle{
position: absolute;
width: 10px;
height: 10px;
border-radius: 50%;
background: red;
}
</style>
</head>
<body>
<div class="circle" id="circle"></div>
</body>
<script type="text/javascript"> function MouseGesture(opt){
opt = opt || {};
if(opt.wise){
//是否 获取顺时针角度,默认为逆时针角度
this._getDeg = this._clockWise;
}else{
this._getDeg = this._antiClockWise;
}
this.distance = opt.distance || 4; //最小有效距离
this.vaildOffsetDeg =opt.vaildOffsetDeg || 80; //有效的差值角度，大于这个值，相当于拖拽无效 this.startPoint = null; //开始的点
this.options = {}; //其他参数 偏移角度 offsetDeg ， 偏移比例 offsetRate this.cache = null; //缓存的数据
} MouseGesture.prototype._clockWise = function (start,end) {
//获取顺时针的角度
return 360 - this._antiClockWise(start,end);
} MouseGesture.prototype._antiClockWise = function (start,end) {
//获取逆时针的旋转角度
var x1 = start.x;
var y1 = start.y;
var x2 = end.x;
var y2 = end.y;
var deg = 0;
if(x1 != x2){
var k = (y1-y2)/(x1-x2);
var a = Math.atan(k);
deg = a * 180 /Math.PI - 90; //弧度转角度
deg = Math.abs(deg);
if( x1 >= x2){
deg = deg + 180;
}
}else{
if(y2 > y1){
deg = 0;
}else{
deg = 180;
}
}
return Math.floor(deg);
} MouseGesture.prototype.transformDeg = function (deg) {
if(deg >= 360){
deg = deg - 360;
}
if(deg < 0 ){
deg = 360 + deg;
}
return deg
} /**
* 计算可用的角度
* @private
*/
MouseGesture.prototype._invalidDeg = function (deg,offsetDeg) {
var $this = this; var vaildOffsetDeg = $this.vaildOffsetDeg || 80; var start = $this.transformDeg(offsetDeg - vaildOffsetDeg);
var end = $this.transformDeg(offsetDeg + vaildOffsetDeg); if(start >= 360 - 2*vaildOffsetDeg){
if(deg <= end){
if(offsetDeg <= end){
return deg - offsetDeg;
}else{
return deg - (360 - offsetDeg);
}
}
if( deg >= start){
if(offsetDeg > start){
return deg - offsetDeg;
}else{
return (360 - deg) + offsetDeg;
}
}
}else{
if(deg <= end && deg >= start){
return offsetDeg - deg;
}
}
return false;
} /**
* 对外的api，设置起始点
* @param start
* @param options
*/
MouseGesture.prototype.setStart = function (start,options,cache) {
options = options || {};
this.startPoint = start; //开始的点
this.options = options; //其他参数,偏移角度 offsetDeg ， 偏移比例 offsetRate this.distance = options.distance || 4; //最小有效距离
this.vaildOffsetDeg = options.vaildOffsetDeg || 80; //有效的差值角度 this.cache = cache || null;
} /**
* 结束之后，清空设置
*/
MouseGesture.prototype.setEnd = function (opt) {
opt = opt || {};
this.distance = opt.distance || 4; //最小有效距离
this.vaildOffsetDeg =opt.vaildOffsetDeg || 80; //有效的差值角度，大于这个值，相当于拖拽无效 this.startPoint = null; //开始的点
this.options = {}; //其他参数
this.cache = null;
} /**
* 获取角度相关信息
* @param end
*/
MouseGesture.prototype.getDegInfo = function (end) {
if(this.startPoint && end){
var obj = {};
var start = {
x:this.startPoint.x,
y:this.startPoint.y
}
var dis = Math.sqrt((start.x - end.x) * (start.x - end.x) + (start.y - end.y)*(start.y - end.y)); obj["distance"] = dis;
if(dis >= this.distance){
var deg = this._getDeg(start,end);
obj["deg"] = this.transformDeg(deg);
obj["missX"] = end.x - start.x;
obj["missY"] = end.y - start.y;
return obj;
}else{
return false;
}
}else{
return false;
}
} /**
* 计算偏移量
*/
MouseGesture.prototype.calcOffset = function (end) {
var $this = this;
var obj = $this.getDegInfo(end);
if(obj){
var offsetDeg = $this.options.offsetDeg || 0;
offsetDeg = $this.transformDeg(offsetDeg);
var missDeg1 = $this._invalidDeg(obj.deg,offsetDeg); //偏移角度,正面
var missDeg2 = $this._invalidDeg($this.transformDeg(obj.deg + 180),offsetDeg); //偏移角度，反面
var missDeg = false;
var digital = 1;
if(missDeg2 !== false){
missDeg = missDeg2;
digital = -1;
} if(missDeg1 !== false){
missDeg = missDeg1;
digital = 1;
} if(missDeg !== false){
//有效的拖拽角度
//计算偏移比例
missDeg = $this.degToRadian(missDeg); var dist = digital * obj.distance * Math.cos(missDeg);
var offsetRate = $this.options.offsetRate || 1; //如果是边，偏移比例应该是 1 ，如果是拐角，偏移比例应该是 Math.sqrt(2)/2
//console.log(missDeg1,missDeg2,obj.deg,offsetDeg,dist,digital);
return dist * offsetRate;
}
}
return false; } MouseGesture.prototype.calcOffsetInfo = function (end) {
var dis = this.calcOffset(end)
if(dis !== false){
var obj = {
distance:dis
}
if(this.cache){
obj["cache"] = this.cache;
}
return obj;
}
return false;
} //角度转弧度
MouseGesture.prototype.degToRadian = function (deg) {
return deg * Math.PI/180;
} //弧度转角度
MouseGesture.prototype.RadianToDeg = function (radian) {
return radian * 180/Math.PI;
} //开始使用 var circle = document.getElementById("circle"); var ins = new MouseGesture({wise:true}); window.addEventListener("mousedown",function(e){
ins.setStart({
x:e.clientX,
y:e.clientY
});
circle.style.left = e.clientX - 5 + "px";
circle.style.top = e.clientY - 5 + "px";
})
window.addEventListener("mousemove",function(e){
if(!ins.startPoint){
return ;
}
var obj = ins.getDegInfo({
x:e.clientX,
y:e.clientY
});
if(obj){
console.log(`角度为:${obj.deg}; x方向位移:${obj.missX}; y方向位移:${obj.missY} ;两点之间的距离为:${obj.distance}`);
}else{
console.log("无效的移动");
}
})
window.addEventListener("mouseup",function(e){
ins.setEnd();
}) </script>
</html>