Fabric js多选移动不会触发单个对象的移动事件答案

【问题标题】：fabric js multi-select moving does not fire single object's moving eventFabric js多选移动不会触发单个对象的移动事件
【发布时间】：2021-01-23 00:40:03
【问题描述】：

如果我有多对对象，例如（A1，A2），（B1，B2），（C1，C2），我想要的是当对象 A1/B1/C1 移动时，对象 A2/B2 /C2 也在移动。当我多选对象时，比如说，A1 和 B1，并移动它们，A2 和 B2 根本不会移动，因为单个对象事件不会触发。我该如何解决？

谢谢！

这里有一支笔来演示：https://codepen.io/taineleau/pen/PdxRKX

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

<head>
    <meta charset="UTF-8">
    <title>Fabric JS playground</title>



    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">


    <script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js'></script>
    <script src='https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.0.0-rc.3/fabric.js'></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

    <style>
        canvas {
            position:relative;
            display:inline-block;
            width:100%;
        }
    </style>

</head>

<body>

<canvas id="fabriccanvas" width="1000px" height="1000px"></canvas>



<script>

    function bind(obj1, obj2) {
        obj1.on("moving", function () {
            obj2.left = this.left + 50;
            obj2.top = this.top;
        });
    }

    var canvas = new fabric.Canvas("fabriccanvas");

    var A1 = new fabric.Rect({
        width: 200, height: 100, left: 0, top: 50, angle: 30,
        fill: 'rgb(255,0,0)'
    });


    var A2 = new fabric.Rect({
        width: 200, height: 100, left: 50, top: 50, angle: 30,
        fill: 'rgba(255,0,0,0.5)',
        selectable: false,
    });

    var B1 = new fabric.Rect({
        width: 100, height: 100, left: 35, top: 25, angle: -10,
        fill: 'rgb(0,200,0)'
    });

    var B2 = new fabric.Rect({
        width: 100, height: 100, left: 85, top: 25, angle: -10,
        fill: 'rgba(0,200,0,0.5)',
        selectable: false,

    });

    bind(A1, A2);
    bind(B1, B2);

    canvas.add(A1, A2, B1, B2);

</script>

</body>

</html>

if I multi-select A1 and B1 and moving them, A2 and B2 don't move at all

【问题讨论】：

FabricJS: object:moving event doesn't fire when user selects multiple objects的可能重复
@Ruzihm 不完全相同。 A2 与 A1 特异性结合。如果我使用全局object:moving，我仍然无法做我想做的事。或者也许我错过了什么。

标签： javascript fabricjs

【解决方案1】：

您可以使用on.("object:moving")，检查它是否与您要绑定的对象匹配，或者它是否包含一个对象，然后进行适当的更新。如果它包含要绑定的对象，则必须将其偏移容器本身的位置和大小。

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

<head>
  <meta charset="UTF-8">
  <title>Fabric JS playground</title>



  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">


  <script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js'></script>
  <script src='https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.0.0-rc.3/fabric.js'></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

  <style>
    canvas {
      position: relative;
      display: inline-block;
      width: 100%;
    }
  </style>

</head>

<body>

  <canvas id="fabriccanvas" width="1000px" height="1000px"></canvas>



  <script>
    function bind(obj1, obj2) {
      canvas.on('object:moving', function(event) {
        if (obj1 == event.target) {
          obj2.left = obj1.left + 50;
          obj2.top = obj1.top;
        } else if ("_objects" in event.target) {
          if (event.target["_objects"].includes(obj1)) {
            obj2.left = obj1.left + event.target.left + event.target.width / 2 + 50;
            obj2.top = obj1.top + event.target.top + event.target.height / 2;
          }
        }
      });

    }

    var canvas = new fabric.Canvas("fabriccanvas");

    var A1 = new fabric.Rect({
      width: 200,
      height: 100,
      left: 0,
      top: 50,
      angle: 30,
      fill: 'rgb(255,0,0)'
    });


    var A2 = new fabric.Rect({
      width: 200,
      height: 100,
      left: 50,
      top: 50,
      angle: 30,
      fill: 'rgba(255,0,0,0.5)',
      selectable: false,
    });

    var B1 = new fabric.Rect({
      width: 100,
      height: 100,
      left: 35,
      top: 25,
      angle: -10,
      fill: 'rgb(0,200,0)'
    });

    var B2 = new fabric.Rect({
      width: 100,
      height: 100,
      left: 85,
      top: 25,
      angle: -10,
      fill: 'rgba(0,200,0,0.5)',
      selectable: false,

    });

    bind(A1, A2);
    bind(B1, B2);

    canvas.add(A1, A2, B1, B2);
  </script>

</body>

</html>

【讨论】：