无法让 svg 元素完全跟随鼠标答案

【问题标题】：Can't get svg element to follow mouse exactly无法让 svg 元素完全跟随鼠标
【发布时间】：2023-03-05 00:47:01
【问题描述】：

我正在使用 Snap svg，我想定位一个元素，使其始终位于鼠标指针下方。我见过各种各样的 tuts，但似乎没有什么是最新的（setAttribute 不在 Snap 文档中，所以我一直在使用转换）。

此代码使元素跟随鼠标，鼠标 x,y 和元素 x,y 之间似乎存在某种平方关系。为什么会这样，我该如何解决？

    var tree1xy = tree1.getBBox();


park.hover(function() {
    follow();
});

    function follow() {

        map.mousemove( moveFunc );

        function moveFunc( ev, x, y ) {
            tree1.transform('t' + (x - tree1xy.x) + ',' + (y - tree1xy.y) );
        };

    };

我在 css 中有这个，但是将所有内容除以三似乎并不能解决问题：

svg {
width: 33%;
height: auto;
}

<head>
    <meta charset="utf-8">

    <link rel="stylesheet" type="text/css" href="css/style.css">
    <script type="text/javascript" src="js/snap.svg-min.js"></script>

    <link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
    <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>

</head>

<body>


    <div id="map">

    </div>


    <script type="text/javascript" src="js/main2.js"></script>

</body>

【问题讨论】：

你能给我们看看HTML/SVG吗？
上传了 html - svg 很大 - 我需要一点时间来制作一个更小的版本。糟透了，我不能只使用图片上传来上传它：/

标签： javascript html css svg snap.svg

【解决方案1】：

我不能确定，但我猜你需要绝对变换而不是相对变换

t=相对变换

T=绝对变换

var s = Snap("#svg")
  , c = s.circle( 10, 10, 10 )
  , coords = document.querySelector('#coords')

s.mousemove(function(ev, x, y) {
  coords.innerText = `${x},${y}`
  var bb = c.getBBox()
    , mx = x - bb.r0
    , my = y - bb.r0
   
  c.transform("T" + mx + "," + my)
})


//t=relative transform, T=absolute transform, s=relative scale, S=absolute Scale
//r=relative rotate, R=relative rotate
//relative means it takes into account previous transforms to accumulate
//here it doesn't make much difference, until we combine later

<script src="https://cdnjs.cloudflare.com/ajax/libs/snap.svg/0.4.1/snap.svg-min.js"></script>
<svg id="svg" width="1024" height="1024"></svg>
<div id="coords"></div>

更新：修改了 OP 小提琴

http://jsfiddle.net/t2qvfLw5/51

var container = Snap('#svg-container')
  , map = container.select("#svg-of-the-park")
  , group = container.select("#group-of-shapes")
  , tree1 = container.select('#tree1')
  , park = container.select('#park')
  , coords = document.querySelector('#coords')	// for debug only
  , in_the_park = false
;

park.attr('fillOpacity', '0')

park.hover(
  function mouseInThePark() {
    in_the_park = true
  }, 
  function mouseLeftThePark() {
    in_the_park = false
  }
)

container.mousemove(function(ev, x, y) {
  if (!in_the_park) return

  var bb = tree1.getBBox()
    , p_bb = group.getBBox()
    , pos_x = Math.floor(
      x
      - bb.x
      - p_bb.x
      + container.node.offsetLeft
      )
    , pos_y = Math.floor(
      y
      - bb.y
      - p_bb.y
      - bb.height
      - container.node.offsetTop
    )
  ;
  
  coords.innerText = `${x},${y} => ${pos_x},${pos_y}`
  
  tree1.transform(
    `translate(${pos_x},${pos_y})`);
});

<script src="http://cdn.jsdelivr.net/snap.svg/0.1.0/snap.svg-min.js"></script>
	<body>
    <div id="coords">...</div>
		<div id="svg-container">
    
    <!-- notice the svg itself gets an element id -->
      <svg 
        id="svg-of-the-park"
        version="1.1"
        xmlns="http://www.w3.org/2000/svg"
        xmlns:xlink="http://www.w3.org/1999/xlink"
        x="0px"
        y="0px"
        width="712.464px"
        height="1000px"
        viewBox="0 0 712.464 900"
        enable-background="new 0 0 712.464 899.955"
        xml:space="preserve"
      >
          <!-- notice also that the group element is not the same as the parent div -->
          <g id="group-of-shapes">
            <polyline id="Large_Triangle" fill="#4E4E4E" points="352.732,31.586 23.392,879.586 673.892,879.586 	"/>
            <polyline id="Sm_Triangle" fill="#4E4E4E" points="462.892,272.391 462.892,272.391 693.892,271.891 
            580.401,577.821 	"/>
            <polyline id="grass" fill="#9FB718" points="389.79,715.391 472.392,602.391 569.059,602.391 605.21,697.967 
            521.392,815.345 417.555,815.344 389.79,780.891 389.79,715.391 	"/>
            <polygon id="tree7" fill="#73850B" points="495.726,796.562 505.892,796.562 505.892,802.062 512.059,802.062 
            512.059,796.562 523.559,796.562 509.642,761.729 	"/>
            <polyline id="tree6" fill="#73850B" points="545.729,593.209 533.059,624.058 543.059,624.058 542.892,629.891 
            547.893,629.891 547.975,624.055 558.482,624.055 545.729,593.209 	"/>
            <polygon id="tree5" fill="#73850B" points="527.392,677.391 514.892,711.391 524.392,711.391 524.392,716.891 
            530.392,716.891 530.392,711.391 540.892,711.391 	"/>
            <polygon id="tree4" fill="#73850B" points="505.726,659.893 495.726,685.726 504.059,685.726 504.059,690.059 
            508.393,690.059 508.393,685.726 516.059,685.726 	"/>
            <polygon id="tree3" fill="#73850B" points="501.393,700.06 491.893,724.727 499.559,724.727 499.559,729.227 
            504.059,729.227 504.059,724.727 512.059,724.727 	"/>
            <polygon id="tree2" fill="#73850B" points="410.726,748.394 421.559,748.394 421.559,754.061 426.893,754.061 
            426.893,748.394 438.226,748.394 424.476,713.727 	"/>
            <polygon id="tree1" fill="#73850B" points="445.726,742.062 435.393,769.514 444.227,769.395 444.226,773.895 
            448.559,773.895 448.559,769.395 457.059,769.229 	"/>
            <polygon id="_x3C_Rd_x5F_7_x3E_" fill="#FFF167" points="467.631,272.38 536.892,367.557 639.225,367.557 639.287,271.992 
            650.287,271.992 650.225,367.557 658.402,367.557 654.801,377.266 650.225,377.266 650.225,389.602 639.559,418.354 
            639.559,377.391 536.892,377.266 516.892,413.224 511.892,399.891 524.642,377.141 503.162,377.141 499.475,367.557 
            524.642,367.557 471.479,294.679 462.892,272.391 	"/>
            <path id="_x3C_Rd_x5F_6_x3E_" fill="#FFF167" d="M536.559,794.105l11.016-15.427c0,0,0.016,67.879,0.016,68.879
            s75.854-101.22,75.854-101.22l5.303,13.986l-16.084,20.583l30.896,41.984l-8.917,7.151l-29.432-40.151l-24.984,34.333
            l41.695,55.362h-14.333l-34.362-46.362l-33.667,46.362h-13.333l10.333-16.029v-67.333"/>
            <polygon id="_x3C_Rd_x5F_5_x3E_" fill="#FFF167" points="351.56,623.558 351.56,733.894 389.79,733.894 389.79,746.338 
            351.56,746.338 351.56,811.558 340.227,811.558 340.227,642.225 	"/>
            <polygon id="_x3C_Rd_x5F_4_x3E_" fill="#FFF167" points="393.227,555.89 399.894,545.89 457.059,623.366 450.185,632.77 	"/>
            <polyline id="_x3C_Rd_x5F_3_x3E_" fill="#FFF167" points="134.227,811.558 147.892,812.534 147.892,589.266 158.621,589.33 
            262.894,740.223 269.227,729.227 205.561,638.89 295.561,638.89 295.561,628.223 198.561,628.223 171.894,589.33 279.667,589.33 
            295.561,609.89 295.561,590.89 191.007,448.002 186.12,460.587 270.553,577.821 140.54,577.948 135.408,591.161 	"/>
            <polygon id="_x3C_Rd_x5F_2_x3E_" fill="#FFF167" points="310.392,516.891 399.892,516.891 393.227,528.891 310.392,528.891 	"/>
            <polygon id="_x3C_Rd_x5F_1_x3E_" fill="#FFF167" points="295.561,381.391 216.877,381.391 212.371,392.994 295.561,392.994 	"/>
            <path id="_x3C_Lg_x5F_rd_x5F_top_x5F_curve_x3E_" fill="#D3D3D3" d="M423.499,838.141c0,0,0,0,0-13.75
            s-11.107-12.833-11.107-12.833"/>
            <path id="_x3C_Lg_x5F_rd_x5F_btm_x3E_" fill="#D3D3D3" d="M254.645,833.354H41.347l-5.213,13.424h354.343l-0.149,32.811
            l12.815-0.003c0,0,0.107-20.771,0.107-33.398s-11.107-12.833-11.107-12.833H258.31H254.645z"/>
            <polygon fill="#D3D3D3" points="295.561,178.793 295.561,686.558 262.894,740.223 262.894,811.558 49.812,811.558 44.599,824.981 
            410.726,824.981 410.478,879.586 423.392,879.586 423.499,824.391 412.392,811.558 278.558,811.558 278.558,742.062 
            491.893,397.225 484.522,378.558 310.392,659.893 310.392,140.605 	"/>
            <circle id="_x3C_Roundabout_x5F_lg_x3E_" fill="#888888" cx="269.906" cy="830.043" r="28.209"/>
            <circle id="_x3C_Roundabout_x5F_sm_x3E_" fill="#C5C5C5" cx="269.867" cy="830.107" r="15.901"/>
          </g>


          <g id="Locations">

          <polyline id="park" fill="#000000" stroke="none" points="473.707,601.598 389.791,714.644 389.791,781.896 
            417.946,815.345 521.232,815.345 605.21,700.06 568.232,602.896 "/>

          </g>

      </svg>
		</div>

	</body>

不幸的是，使用 css 缩放确实把它扔掉了，我认为用不同的方式重新调整大小会更容易

【讨论】：

我试过了 - 它没有用，但显然 Snap 和绝对变换有问题？
这显然是正确的方法，但我无法在我的 svg 中重新定位我的元素 - 它似乎是从 .我特别不明白旋转行为？恐怕我对 svg 和 Snap 还是很陌生。 t 和 T 似乎对我做同样的事情
@Davtho1983 如果您可以展示一个损坏的 jsfiddle，那么我们也许可以为您提供更多帮助，我粘贴的示例似乎可以正常工作
那个小提琴有一些问题。没有#park 元素，例如您有2 个#map id。您还在 div id 上使用了选择（如果是#map），因此您要确保选择唯一的 SVG id（可以通过重命名地图的大写/小写来区分。
我更新了您的示例 jsfiddle.net/t2qvfLw5/51 不幸的是，正如您所说，使用 css 缩放将其全部抛出。