如何使用自定义挂钩访问结构 object 以将背景图像添加到 canvas？

Question

So I'm working on this editor where a user can upload an image and edit it on the canvas. To achieve this I'm using React and FabricJS. Besides everything I have tried to make an editor, FabricJS seemed to have what I want. And as FabricJS doesn't have native support for react I have been looking for a workaround to make it work with React. And I stumbled upon this answer here and trying to use it.

This custom hook from that answer eliminates another issue which is adding multiple nested canvas wrappers.

Right now it is working fine if I just use a background color but it throws an error when I try to add a background image. Seems like the fabric object is not accessible. And I'm not sure how I can access it.

Here's the error:

TypeError: Cannot read properties of undefined (reading 'fromURL')

So I'm posting here if someone has an idea on how to add background image, or different shapes to the canvas using the fabric object but also using this hook as it eliminates nested fabric wrappers.

Here's the CodeSandbox .

Here's the code:

import { useCallback, useRef } from "react";
import { fabric } from "fabric";

const useFabric = (onChange) => {

    const fabricRef  = useRef();
    const disposeRef = useRef();

    return useCallback((node) => {
        if (node) {
             fabricRef.current = new fabric.Canvas(node);

             if (onChange) {
                  disposeRef.current = onChange(fabricRef.current);
             }

         } else if (fabricRef.current) {

              fabricRef.current.dispose();

              if (disposeRef.current) {
                   disposeRef.current();
                   disposeRef.current = undefined;
              }
         }
     }, []);

};


export default function App() {

     const ref = useFabric((fabricCanvas) => {

           fabricCanvas.backgroundColor = "green";

           // fabricCanvas.Image.fromURL("https://i.imgur.com/8zvUjul.jpg", function ( img ) {
           //     fabricCanvas.add(img);
           //     fabricCanvas.sendToBack(img);
           // });

          fabricCanvas.renderAll();
     });

     return (
         <div>
             <canvas ref={ref} id="canvas" />
         </div>
     );
}

Answer 1

You're calling .Image.FromUrl to the canvas instance not the fabric object.

Try

fabric.Image.fromUrl...

instead of

fabricCanvas.Image.fromURL