js——鼠标拖拽缩放

2023-09-24  本文已影响0人  弦生_a3a3

案例图片展示:

image.png

代码块:


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    *{
        margin: 0;
        padding: 0;
        list-style: none;
    }
    body{
        position: relative;
    }
    #demo{
        position: absolute;
        left: 20px;
        top: 20px;
        border: 1px solid red;
        width: 300px;
        height: 300px;
    }
    #demo>p{
        width: 10px;
        height: 10px;
        background-color: #000;
        position: absolute;
    }
    .top-left{
        left: -5px;
        top: -5px;
    }
    .top-rig{
        right:-5px;
        top:-5px;
    }
    .bt-left{
        left:-5px;
        bottom:-5px;
    }
    .bt-rig{
        right:-5px;
        bottom:-5px;
    }
</style>
<body>
    <div id="demo">
        <p class="top-left"></p>
        <p class="top-rig"></p>
        <p class="bt-left"></p>
        <p class="bt-rig"></p>
    </div>
<script>
    let demo = document.getElementById('demo');
    const [ tl,tr,bl,br ] = demo.children;
    let data = {
        move:false,
        offsetX:0,
        slace:false,
        slasceX:0,
        slasceY:0,
        slasceDemoH:0,
        slasceDemoT:0,
        slasceDemoW:0,
        slasceDemoWL:0,
        domW:0,
        domH:0,
        offsetY:0,
        className:''
    };
    data.domW = demo.offsetWidth;
    data.domH = demo.offsetHeight;
    demo.addEventListener('mousedown',({clientX,clientY})=>{
        data.offsetX = clientX - demo.offsetLeft;
        data.offsetY = clientY - demo.offsetTop;
        data.move = true;
    });
    window.addEventListener('mousemove',({clientX,clientY})=>{
        if(data.move){
            let left = clientX - data.offsetX;
            let top = clientY - data.offsetY;
            let maxW = window.innerWidth - demo.offsetWidth -5;
            let maxH = window.innerHeight - demo.offsetHeight -5;
            if(left<=0) return;
            if(top<=0) return;
            if(left>=maxW) left = maxW; 
            if(top>=maxH) top = maxH; 
            demo.style['left'] =left +'px';
            demo.style['top'] = top +'px';
        }
    });
    window.addEventListener('mouseup',()=>{
        data.move = false;
        data.slace = false;
    });
    const rigMoveDown = dom =>{
        dom.addEventListener('mousedown',e=>{
            e.stopPropagation();
            const { clientX,clientY,target } = e;
            data.className=target.classList['0'];
            data.slasceX = clientX;
            data.slasceY = clientY;
            data.slasceDemoH = demo.offsetHeight;
            data.slasceDemoW = demo.offsetWidth;
            data.slasceDemoT = demo.offsetTop;
            data.slasceDemoWL = demo.offsetLeft;
            data.slace = true;
        })
    };
    rigMoveDown(br);
    rigMoveDown(tr);
    rigMoveDown(tl);
    rigMoveDown(bl);
    window.addEventListener('mousemove',e=>{
        e.stopPropagation();
        if(data.slace){
            const { clientX,clientY } = e;

            let y = clientY - data.slasceY;
            let x = clientX - data.slasceX;
            let height = data.slasceDemoH - y;
            let width = data.slasceDemoW - x;
            if(height<=10) return height = 10;
            if(width<=10) return width = 10;
            console.log("x-y",x,y)
            switch(data.className){
                case 'bt-rig':
                demo.style['width'] = clientX - demo.offsetLeft + 'px';
                demo.style['height'] = clientY - demo.offsetTop + 'px';
                break;
                case 'top-rig':
                demo.style['height'] = height + 'px';
                demo.style['top'] =  data.slasceDemoT + y + 'px';
                demo.style['width'] = clientX - demo.offsetLeft + 'px';
                break;
                case 'top-left':
                console.log("x",x)
                demo.style['height'] = height + 'px';
                demo.style['top'] =  data.slasceDemoT + y + 'px';
                demo.style['left'] =  data.slasceDemoWL + x + 'px';
                demo.style['width'] = width + 'px';
                break;

                case 'bt-left':
                demo.style['height'] = data.slasceDemoH + y + 'px';
                demo.style['left'] =  data.slasceDemoWL + x + 'px';
                demo.style['width'] = width + 'px';
                break;
            }
        }
    });
</script>
</body>
</html>

作者太懒了都不想解释,仔细斟酌

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