拖拽编写SVG图形化工具(二)-LMLPHP

getAttributesNs/setAttributesNs

element.setAttributeNS(namespace,name,value)

namespace 是指定属性的命名空间的一个字符串。
name 是标识要设置的属性的一个字符串。
value 是新属性的所需字符串值。

添加/或者查询一个新属性或更改具有给定命名空间和名称的一个属性的值。

应用demo

程序思路

首先我们看看代码映射

 // 按下
  box.onmousedown = function (event) {
    console.log(1);
    // 移动
    box.onmousemove=function () {
      console.log(2);
    }
    // 抬起
    box.onmouseup=function () {
      console.log(3);
    }
  }

整体的逻辑就是

鼠标按下开始的时候,记录当前的坐标,拿到点击的那个dom

后续鼠标移动的时候, 当前的坐标-开始的坐标的差值=本来应该指向的坐标

并且移动的时候要设置一定的范围,以便更新点不能离开当前的范围

鼠标离开的时候,关闭移动/松开的事件

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    #container {
      width: 100%;
      height: 500px;
      background-color: #fff;
      margin: 0 auto;
      text-align: center;
    }

    path {
      stroke-width: 8;
      stroke: #1E1935;
      stroke-linecap: round;
      fill: none;
    }

    circle {
      stroke-width: 2;
      stroke: #ef2d56;
      fill: #fff;
    }

    circle:hover {
      fill: #ef2d56;
      cursor: move;
    }

    line {
      stroke-width: 1;
      stroke: #999;
      stroke-linecap: round;
      stroke-dasharray: 5, 3;
    }

    path {
      stroke-width: 2;
      stroke: #1E1935;
      stroke-linecap: round;
      /* fill: none; */
    }

    path.fill {
      fill: #1E1935
    }
  </style>
</head>
<body>
<div style="text-align: center">
  <pre id="code" style="font-size: 40px;font-family: Consolas;">code</pre>
</div>
<div id="container" class="C">
  <svg id="svg" viewBox="0 0 499 499" width="500" height="500"
       preserveAspectRatio="xMidYMid meet">
    <g id="main">
      <circle id="p1" cx="100" cy="250" r="16"/>
      <circle id="p2" cx="400" cy="250" r="16"/>

      <circle id="c1" cx="100" cy="100" r="8"/>
      <circle id="c2" cx="400" cy="100" r="8"/>

      <line id="l1" x1="100" y1="250" x2="100" y2="100"/>
      <line id="l2" x1="400" y1="250" x2="400" y2="100"/>

      <path id="path" d="M100,250 C100,100 400,100 400,250"/>
    </g>
  </svg>
</div>
<script>
  let svg = document.getElementById('svg'),
    container = document.getElementById('container')
  let point = {}, line = {}
    , maxX = container.offsetWidth - 5
    , maxY = container.offsetHeight - 5,
    fill = false,
    code = document.getElementById('code'),
    // 状态
    drap = null,
    dPonit;

  function init() {
    let circle = svg.getElementsByTagName('circle');
    for (let i = 0; i < circle.length; i++) {
      point[circle[i].getAttributeNS(null, 'id')] = {
        x: +circle[i].getAttributeNS(null, 'cx'),
        y: +circle[i].getAttributeNS(null, 'cy'),
      }
    }
    line.l1 = svg.getElementById('l1')
    line.l2 = svg.getElementById('l2')
    line.path = svg.getElementById('path')
    svg.onmousedown = document.onmousemove = document.onmouseup = Drag
    svg.ontouchstart = document.ontouchmove = document.ontouchend = Drag
  }

  // 鼠标范围限制
  function PointM(x, y) {
    return {
      x: Math.max(0, Math.min(maxX, x)),
      y: Math.max(0, Math.min(maxY, y))
    }
  }


  function Drag(e) {
    e.stopPropagation()
    let t = e.target, id = t.id, et = e.type, m = PointM(e.pageX, e.pageY);
    // 鼠标按在path区域
    if (!drap && id === 'path' && et === 'mousedown') {
      fill = !fill;
      t.setAttributeNS(null, 'class', (fill ? 'fill' : ''))
      DragGet();
    }
    // 鼠标按在开始
    // typeof(point[id]!==undefined) 意思就是要按在这几个点上
    if (!drap && ['p1', 'p2', 'c1', 'c2'].includes(id) && (et === 'mousedown' || et === 'touchstart')) {
      drap = t;
      dPonit = m
    }
    // 移动的时候
    if (drap && ['p1', 'p2', 'c1', 'c2'].includes(id) && (et === 'mousemove' || et === 'touchmove')) {
      console.log(id);
      // 当前的坐标-开始的坐标等于差值
      point[id].x += m.x - dPonit.x;
      point[id].y += m.y - dPonit.y;
      if (point[id].x < maxX && point[id].y < maxY) {
        id = drap.id;
        dPonit = m;
        drap.setAttributeNS(null, "cx", point[id].x);
        drap.setAttributeNS(null, "cy", point[id].y);
      }
      DragGet()
    }

    // 松开的时候
    if (drap && (et === "mouseup" || et === "touchend")) {
      drap = null;
    }
  }

  // 更新数据
  function DragGet() {
    // line1
    line.l1.setAttributeNS(null, 'x1', point.p1.x);
    line.l1.setAttributeNS(null, 'y1', point.p1.y);
    line.l1.setAttributeNS(null, 'x2', point.c1.x);
    line.l1.setAttributeNS(null, 'y2', point.c1.y);
    // line2
    line.l2.setAttributeNS(null, 'x1', point.p2.x)
    line.l2.setAttributeNS(null, 'y1', point.p2.y)
    line.l2.setAttributeNS(null, 'x2', point.c2.x)
    line.l2.setAttributeNS(null, 'y2', point.c2.y)
    let d = `M ${point.p1.x},${point.p1.y} C ${point.c1.x},${point.c1.y} ${point.c2.x},${point.c2.y} ${point.p2.x},${point.p2.y}${fill ? 'Z' : ''}`
    line.path.setAttributeNS(null, 'd', d)
    code.textContent = d;
  }

  init()

</script>
</body>
</html>

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拖拽编写SVG图形化工具(二)

getAttributesNs/setAttributesNs

应用demo