svg中自动吸附靠近的物体

var attractSwitch = true;//自动吸附开关，true 为开启，否则关闭

//矩形物体类别枚举
var T_PDU = 'PDU';
var T_AC = 'AC';
var T_CABINET = 'CABINET';
var T_FLOOR = 'FLOOR';

var magicalLength = 10;//矩形物体边缘的垂直距离小于等于此长度则自动吸附

var rectsPdu = new ArrayList();
var rectsAC = new ArrayList();
var rectsCabinet = new ArrayList();
var rectsFloor = new ArrayList();
/**
* 吸附
*/
function attract(moveObj) {
if (!attractSwitch) {
return null;
}
var findAttractObj = false;
var currentXOffset = 10000;
var currentYOffset = 10000;
for (var i = 0; i < rectsPdu.size(); i++) { //遍历PDU
var item = rectsPdu.get(i);
if (!item.equals(moveObj)) {               //若不是当前移动的PDU
if (moveObj.underneath(item)) {//移动的物体在下侧
if (!moveObj.onRight(item) && !moveObj.onLeft(item)) {
var length = moveObj.y - (item.y + item.height);
if (length <= magicalLength) {
findAttractObj = true;
if (length < Math.abs(currentYOffset)) {
//moveObj.y = moveObj.y - length;
currentYOffset = -length;
}
// return moveObj;
}
}
} else if (moveObj.onLeft(item)) {//移动的物体在左侧
if (!moveObj.onTop(item) && !moveObj.underneath(item)) {
var length = item.x - (moveObj.x + moveObj.width);
if (length <= magicalLength) {
findAttractObj = true;
if (length < Math.abs(currentXOffset)) {
// moveObj.x = moveObj.x + length;
currentXOffset = length;
}
//  return moveObj;
}
}
} else if (moveObj.onTop(item)) {//移动的物体在上侧
if (!moveObj.onRight(item) && !moveObj.onLeft(item)) {
var length = item.y - (moveObj.y + moveObj.height);
if (length <= magicalLength) {
findAttractObj = true;
if (length < Math.abs(currentYOffset)) {
//moveObj.y = moveObj.y + length;
currentYOffset = length;
}
// return moveObj;
}
}
} else if (moveObj.onRight(item)) { //移动的物体在右侧
if (!moveObj.onTop(item) && !moveObj.underneath(item)) {
var length = moveObj.x - (item.x + item.width);
if (length <= magicalLength) {
findAttractObj = true;
if (length < Math.abs(currentXOffset)) {
//moveObj.x = moveObj.x - length;
currentXOffset = -length;
}
// return moveObj;
}
}
} else {//移动物体和目标交叉
continue
}
}
}
if (findAttractObj) {
if (currentXOffset < magicalLength) {
moveObj.x = moveObj.x + currentXOffset;
}
if (currentYOffset < magicalLength) {
moveObj.y = moveObj.y + currentYOffset;
}
return moveObj;
}
return null;

}

function add(obj) {
if (rectObj.rType == T_PDU) {
rectsPdu.add(obj);
} else if (rectObj.rType == T_AC) {
rectsAC.add(obj);
} else if (rectObj.rType == T_CABINET) {
rectsCabinet.add(obj);
} else if (rectObj.rType == T_FLOOR) {
rectsFloor.add(obj);
}

}

function remove(obj) {
if (rectObj.rType == T_PDU) {
rectsPdu.remove(obj);
} else if (rectObj.rType == T_AC) {
rectsAC.remove(obj);
} else if (rectObj.rType == T_CABINET) {
rectsCabinet.remove(obj);
} else if (rectObj.rType == T_FLOOR) {
rectsFloor.remove(obj);
}
}

function update(obj) {
if (rectObj.rType == T_PDU) {
rectsPdu.update(obj);
} else if (rectObj.rType == T_AC) {
rectsAC.update(obj);
} else if (rectObj.rType == T_CABINET) {
rectsCabinet.update(obj);
} else if (rectObj.rType == T_FLOOR) {
rectsFloor.update(obj);
}
}

/**
* 求两点之间的距离
* @x1 点1x坐标
* @y1 点1y坐标
* @x2 点2x坐标
* @y2 点2y坐标
*/
function getTwoPointLength(x1, y1, x2, y2) {
return Math.sqrt(Math.pow((x1 - x2), 2) + Math.pow((y1 - y2), 2));
}