var initHeading = 0;
var rotation = 0;
var lastTime;
function setGesture(el) {
var obj = {};
var istouch = false;
var start = [];
el.addEventListener("touchstart", function (e) {
if (e.touches.length >= 2) { //判断是否有两个点在屏幕上
istouch = true;
start = e.touches; //得到第一组两个点
obj.gesturestart && obj.gesturestart.call(el); //执行gesturestart方法
};
}, false);
document.addEventListener("touchmove", function (e) {
e.preventDefault();
if (e.touches.length >= 2 && istouch) {
var now = e.touches; //得到第二组两个点
var scale = getDistance(now[0], now[1]) / getDistance(start[0], start[1]); //得到缩放比例，getDistance是勾股定理的一个方法
var rotation = getAngle(now[0], now[1]) - getAngle(start[0], start[1]); //得到旋转角度，getAngle是得到夹角的一个方法
e.scale = scale.toFixed(2);
e.rotation = rotation.toFixed(2);
obj.gesturemove && obj.gesturemove.call(el, e); //执行gesturemove方法
};
}, false);
document.addEventListener("touchend", function (e) {
if (istouch) {
istouch = false;
obj.gestureend && obj.gestureend.call(el); //执行gestureend方法
};
}, false);
return obj;
};
function getDistance(p1, p2) {
var x = p2.pageX - p1.pageX,
y = p2.pageY - p1.pageY;
return Math.sqrt((x * x) + (y * y));
};
function getAngle(p1, p2) {
var x = p1.pageX - p2.pageX,
y = p1.pageY - p2.pageY;
return Math.atan2(y, x) * 180 / Math.PI;
};
var box = document.querySelector("#map3d");
var boxGesture = setGesture(box); //得到一个对象
boxGesture.gesturestart = function () { //双指开始
/*box.style.backgroundColor="yellow";*/
initHeading = map25D._coreMap.map.position.heading;
};
boxGesture.gesturemove = function (e) { //双指移动
rotation = parseInt(e.rotation);
var time = new Date().getTime();
var realRotation = changeAngle(rotation, time);
if (realRotation) {
//TODO 得到旋转角度后想实现的功能
map25D._coreMap.map.position.setHeading(realRotation);
map25D._coreMap.map.renderer.update();
}
};
boxGesture.gestureend = function () { //双指结束
};
//通过时间判断解决叠加初始方向
var changeAngle = function (heading, newTime) {
if ((newTime - lastTime) < 2) {
return false;
}
lastTime = newTime;
return (initHeading + heading)
}
