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JavaScript實現(xiàn)矩形塊大小任意縮放

發(fā)布時間:2020-09-12 15:32:18 來源:腳本之家 閱讀:182 作者:布湫 欄目:開發(fā)技術(shù)

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,,里分享源碼給大家,一起學(xué)習一下。

<!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)習有所幫助,也希望大家多多支持億速云。

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