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JavaScript實現(xiàn)矩形塊大小任意縮放

更新時間：2020年08月25日 12:31:38 作者：布湫

這篇文章主要為大家詳細介紹了JavaScript實現(xiàn)矩形塊大小任意縮放，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

最近寫了一個原生JavaScript實現(xiàn)矩形塊大小任意縮放的案例，感覺里面的東西比較的繞，這里分享源碼給大家，一起學(xué)習(xí)一下。

<!DOCTYPE html>
<html lang="en">

<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>原生JavaScript實現(xiàn)矩形塊大小任意縮放</title>
</head>
<style>
 * {
  margin: 0;
  padding: 0;
 }

 .box {
  position: relative;
  top: 200px;
  left: 500px;
  width: 500px;
  height: 300px;
  background-color: blueviolet;
 }

 .box>div:nth-child(-n+4) {
  position: absolute;
  width: 5px;
  height: 5px;
  background-color: #cc00ff;
 }

 .box>div:nth-child(n+5) {
  position: absolute;
  background-color: #f30497;
 }

 .box>.dot1 {
  cursor: nw-resize;
  top: -5px;
  left: -5px;
 }

 .box>.dot2 {
  cursor: ne-resize;
  top: -5px;
  right: -5px;
 }

 .box>.dot3 {
  cursor: se-resize;
  bottom: -5px;
  right: -5px;
 }

 .box>.dot4 {
  cursor: sw-resize;
  bottom: -5px;
  left: -5px;
 }

 .box>.line1,
 .box>.line3 {
  width: 500px;
  height: 5px;
 }

 .box>.line1 {
  top: -5px;
  cursor: n-resize;
 }

 .box>.line3 {
  bottom: -5px;
  cursor: s-resize;
 }

 .box>.line2,
 .box>.line4 {
  width: 5px;
  height: 300px;
 }

 .box>.line2 {
  right: -5px;
  cursor: e-resize;
 }

 .box>.line4 {
  left: -5px;
  cursor: e-resize;
 }
</style>

<body>
 <div class="box">
  <div class="dot1"></div>
  <div class="dot2"></div>
  <div class="dot3"></div>
  <div class="dot4"></div>
  <div class="line1"></div>
  <div class="line2"></div>
  <div class="line3"></div>
  <div class="line4"></div>
 </div>
 <script>
  //獲取相關(guān)元素節(jié)點
  let box = document.querySelector(".box");
  let dots = document.querySelectorAll(".box>div:nth-child(-n+4)");
  let lines = document.querySelectorAll(".box>div:nth-child(n+5)");
  // 類邊框?qū)挾?
  let bd = 5;
  //for循環(huán)指定事件對象
  function changeBox([box, dots, lines, bd]) {
   for (let i = 0; i < 4; i++) {
    let { 0: dot1, 1: dot2, 2: dot3, 3: dot4 } = dots;  //dots對象解構(gòu)
    let { 0: line1, 1: line2, 2: line3, 3: line4 } = lines;  //lines對象解構(gòu)
    //矩形頂點點擊拖動調(diào)整大小
    dots[i].onmousedown = function (ev) {
     //點擊事件初始化相關(guān)值
     let oldY = ev.clientY;  //頂點原本的y值
     let oldX = ev.clientX;  //頂點原本的x值
     let h = box.clientHeight; //box的高度
     let w = box.clientWidth; //box的寬度
     let t = box.offsetTop;  //box距離頂部的top值
     let l = box.offsetLeft;  //box距離左邊的left值
     window.onmousemove = function (e) {
      let offsetY = e.clientY - oldY;   //鼠標移動y軸偏移量
      let offsetX = e.clientX - oldX;   //鼠標移動x軸偏移量
      //if條件是判斷鼠標點擊的節(jié)點目標對象
      if (i == 0) {
       box.style.height = `${h - offsetY + bd}px`;  //box高度變化
       box.style.top = `${t + offsetY - bd}px`;  //box的top值變化(定位)
       box.style.width = `${w - offsetX + bd}px`;  //box的寬度變化
       box.style.left = `${l + offsetX - bd}px`;  //box的left值變化(定位)
      } else if (i == 1) {
       box.style.height = `${h - offsetY + bd}px`;
       box.style.top = `${t + offsetY - bd}px`;
       box.style.width = `${w + offsetX + bd}px`;
      } else if (i == 2) {
       box.style.height = `${h + offsetY + bd}px`;
       box.style.width = `${w + offsetX + bd}px`;
      } else if (i == 3) {
       box.style.height = `${h + offsetY + bd}px`;
       box.style.width = `${w - offsetX + bd}px`;
       box.style.left = `${l + offsetX - bd}px`;
      }
      //邊框線的高度/寬度隨著box的大小變化而變化
      line1.style.width = box.style.width;
      line2.style.height = box.style.height;
      line3.style.width = box.style.width;
      line4.style.height = box.style.height;
     }
    }
    //邊框點擊拖動調(diào)整大小
    lines[i].onmousedown = function (ev) {
     //點擊事件初始化相關(guān)值
     let oldY = ev.clientY;   //頂點原本的y值   
     let oldX = ev.clientX;   //頂點原本的x值
     let h = box.clientHeight;  //box的高度
     let w = box.clientWidth;  //box的寬度
     let t = box.offsetTop;   //box距離頂部的top值
     let l = box.offsetLeft;   //box距離左邊的left值
     window.onmousemove = function (e) {
      let offsetX = e.clientX - oldX;  //鼠標移動x軸偏移量
      let offsetY = e.clientY - oldY;  //鼠標移動y軸偏移量
      //if條件是判斷鼠標點擊的節(jié)點目標對象
      if (i == 0) {
       box.style.height = `${h - offsetY + bd}px`;
       box.style.top = `${t + offsetY - bd}px`;
      } else if (i == 1) {
       box.style.width = `${w + offsetX + bd}px`;
      } else if (i == 2) {
       box.style.height = `${h + offsetY + bd}px`;
      } else {
       box.style.width = `${w - offsetX + bd}px`;
       box.style.left = `${l + offsetX - bd}px`;
      }
      //邊框線的高度/寬度隨著box的大小變化而變化
      line1.style.width = box.style.width;
      line2.style.height = box.style.height;
      line3.style.width = box.style.width;
      line4.style.height = box.style.height;
     }
    }
    //鼠標抬起后清除鼠標移動事件
    window.onmouseup = function () {
     window.onmousemove = false;
    }
   }
  }
  changeBox([box, dots, lines, bd])
 </script>
</body>

</html>

以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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