javascript - 无法将 FabricJS svg 或组对象移动到 Canvas 左上角

Question

我正在开发一个 FabricJS 应用程序，我希望用户通过简单的单击即可将对象移动到 Canvas 原点，即使在旋转或缩放对象或一组对象之后也是如此。为此，当用户单击时，我会执行以下代码:

obj.left= obj.getBoundingRect().width/2;
obj.top=obj.getBoundingRect().height/2;

它与矩形或文本完美配合，但在使用形状、svg 甚至对象组时根本不起作用。我不知道为什么!

下面是完整的代码。

重要提示:请在浏览器中启用跨源访问才能加载 svg。

    this.__canvas = new fabric.Canvas('meCanvas', {
        preserveObjectStacking: true,
        height: 400,
        width: 400,
        backgroundColor: '#1F1F1F',
        canvasKey:'azpoazpoaz'
    });
   let rect = new fabric.Rect({
        fill: 'red',
        width: 200,
        height: 100,
        left: 100,
        top: 100,
        originX: 'center',
        originY: 'center',
        fontWeight: 'normal'
    });

    let text = new fabric.IText('Text', {
        fontFamily: 'Times',
        fontSize: 18,
        fill: 'white',
        left: 100,
        top: 100,
        originX: 'center',
        originY: 'center',
        fontWeight: 'normal'
    });

    let url = 'https://svgshare.com/i/9DX.svg';
    fabric.loadSVGFromURL(url,(objects,options)=> {

        let loadedObjects = fabric.util.groupSVGElements(objects, options);
        loadedObjects.left=50;
        loadedObjects.top=150;
        this.__canvas.add(loadedObjects);
    });

    let url2 = 'https://svgshare.com/i/9Cp.svg';
    fabric.loadSVGFromURL(url2,(objects,options)=> {

        let loadedObjects = fabric.util.groupSVGElements(objects, options);
        loadedObjects.left=100;
        loadedObjects.top=200;
        loadedObjects.angle=20;
        this.__canvas.add(loadedObjects);
    });

    this.__canvas.add(rect);
    this.__canvas.add(text);
    this.__canvas.renderAll();

    $('#pushorigin').click((e)=>{
        let obj = this.__canvas.getActiveObject();
        obj.left= obj.getBoundingRect().width/2;
        obj.top=obj.getBoundingRect().height/2;
        this.__canvas.requestRenderAll();
    });

<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.js"></script>
    <div style='display: inline-block'>
        <div>
            <canvas id='meCanvas' ref='meFabric'/>
        </div>
        <div>
            <button id='pushorigin'>Push to origin</button>
        </div>
    </div>

如果您选择文本或矩形并单击“推到原点”按钮，它们将转到原点(左上角)。但同样的 Action 不适用于 svg(三 Angular 形和多边形)，如果我们拉伸(stretch)这些 svg 甚至旋转它们，情况会更糟，它们不会到达原点。使用一组对象时同样如此!

我不知道该怎么办，我迷路了。我用谷歌搜索了好几天，但一无所获。

请帮忙!

Answer 1

为所有对象设置 originX: 'center',originY: 'center' 然后您的解决方案将起作用。

this.__canvas = new fabric.Canvas('meCanvas', {
  preserveObjectStacking: true,
  height: 400,
  width: 400,
  backgroundColor: '#1F1F1F',
  canvasKey: 'azpoazpoaz'
});
let rect = new fabric.Rect({
  fill: 'red',
  width: 200,
  height: 100,
  left: 100,
  top: 100,
  originX: 'center',
  originY: 'center',
  fontWeight: 'normal'
});

let text = new fabric.IText('Text', {
  fontFamily: 'Times',
  fontSize: 18,
  fill: 'white',
  left: 100,
  top: 100,
  originX: 'center',
  originY: 'center',
  fontWeight: 'normal'
});

let url = 'https://svgshare.com/i/9DX.svg';
fabric.loadSVGFromURL(url, (objects, options) => {

  let loadedObjects = fabric.util.groupSVGElements(objects, options);
  loadedObjects.set({
    left: 50,
    top: 150,
    originX: 'center',
    originY: 'center'
  })

  this.__canvas.add(loadedObjects);
});

let url2 = 'https://svgshare.com/i/9Cp.svg';
fabric.loadSVGFromURL(url2, (objects, options) => {
  let loadedObjects = fabric.util.groupSVGElements(objects, options);
  loadedObjects.set({
    left: 100,
    top: 200,
    angle: 20,
    originX: 'center',
    originY: 'center'
  })
  this.__canvas.add(loadedObjects);
});

this.__canvas.add(rect);
this.__canvas.add(text);
this.__canvas.renderAll();

$('#pushorigin').click((e) => {
  let obj = this.__canvas.getActiveObject();
  obj.set({
    left: obj.getBoundingRect().width / 2,
    top: obj.getBoundingRect().height / 2
  }).setCoords()
  this.__canvas.requestRenderAll();
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.js"></script>
<div style='display: inline-block'>
    <div>
        <canvas id='meCanvas' ref='meFabric'/>
    </div>
    <div>
        <button id='pushorigin'>Push to origin</button>
    </div>
</div>