吸附功能开发
更新时间: 2021-08-04 15:08:44
上午刚写完辅助线，下午趁热把吸附给写了~先放效果图吧：
# 原理分析
吸附发生在拖动元素的时候，拖动的时候，当前正在拖动的元素抽象出的8个点是图中的白点，和这8个点对比的点是其他元素的绿点
分别对比这些点的x或y的距离，如果小于设定的距离，比如说5px,就改变当前元素的x或y让这个距离变成0。
# 代码
原理很简单，代码如下：
import { getPoints } from '../utils/common'
export function countAdsorb(e,moveX,moveY) {
const DISTANCE = 5
if(this.constructor._instanceList.length < 2){
return false
}
//首先找到需要对比的点和被对比的点
const currentList = [] //当前元素的8个点
const compareList = [] //其他元素的点
for(let i = 0;i< this.constructor._instanceList.length; i++) {
const instance = this.constructor._instanceList[i]
if(instance.parentEl === this.parentEl && instance.id !== this.id) {
compareList.push(...getPoints(instance))
}else if(instance.parentEl === this.parentEl && instance.id == this.id){
currentList.push(...getPoints(instance))
}
}
if(compareList.length == 0) {
return false
}
let flag = false
let res = ''
//计算它们x和y坐标的差值，如果绝对值小于5就吸附上去，吸附了其中一个就退出循环
for(let i = 0;i < currentList.length; i++) {
const x = currentList[i].x
const y = currentList[i].y
for(let j = 0;j < compareList.length; j++) {
const cx = compareList[j].x
if(Math.abs(x - cx) <= DISTANCE) {
const dis = x - cx
flag = true
res += 'x'
this.x = this.x - dis
this.xCenter = this.x + (this.width / 2)
this.x1 = this.x + this.width
break;
}
}
for(let j = 0;j < compareList.length; j++) {
const cy = compareList[j].y
if(Math.abs(y - cy) <= DISTANCE) {
const dis = y - cy
flag = true
res += 'y'
this.y = this.y - dis
this.yCenter = this.y + (this.height / 2)
this.y1 = this.y + this.height
break;
}
}
if(flag){
break;
}
}
//根据变动的是x还是y分量来修正this.dragOrigin的值
if(res == 'x') {
if(Math.abs(moveX) > DISTANCE) {
this.dragOrign.x = e.pageX
}
this.dragOrign.y = e.pageY
}
if(res == 'y') {
if(Math.abs(moveY) > DISTANCE) {
this.dragOrign.y = e.pageY
}
this.dragOrign.x = e.pageX
}
if(res == 'xy') {
if(Math.abs(moveX) > DISTANCE) {
this.dragOrign.x = e.pageX
}
if(Math.abs(moveY) > DISTANCE) {
this.dragOrign.y = e.pageY
}
}
if(flag) {
return true
}else{
return false
}
}
export function registerAdsort(_this) {
_this.countAdsorb = countAdsorb.bind(_this)
}
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