How can I add and resize images from URLs into an HTML canvas using fabric.js?

Question

I have an array with a bunch of images:

const imgSrcs = ["dashavatar1.jpg", "dashavatar2.jpg", "dashavatar 3.jpg"];

And I'm creating image object from that using the Image constructor:

const images = [];

for (i = 0; i < imgSrcs .length; i++) {
  const image = new Image();
  images.push(image);
}

Now I want to assign the image source and add these image objects on the canvas using fabric.js.

Answer 1

You need to load those images first using const img = new Image(), wait until they are loaded using image.onload and then use ctx.drawImage(img, x, y, width, height) to render it into the canvas:

const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
const innerWidth = canvas.width = window.innerWidth;
const innerHeight = canvas.height = window.innerHeight;
const images = [
  'https://i.sstatic.net/L5XWd.png',
  'https://i.sstatic.net/SnOAO.png',
];

images.forEach((src, i) => {
  const image = new Image();
  image.src = src;

  image.onload = () => {
    ctx.drawImage(image, innerWidth / 2 - 16, 8 + 40 * i, 32, 32);
  };
});

body {
  margin: 0;
  height: 100vh;
}

#canvas {
  width: 100%;
  height: 100%;
}

<canvas id="canvas"></canvas>

With frabric.js you would do the same thing but using their own fabric.Image.fromUR function:

const canvas = new fabric.Canvas('canvas');
const innerWidth = canvas.width = window.innerWidth;
const innerHeight = canvas.height = window.innerHeight;
const images = [
  'https://i.sstatic.net/L5XWd.png',
  'https://i.sstatic.net/SnOAO.png',
];

canvas.setWidth(innerWidth);
canvas.setHeight(innerHeight);

images.forEach((src, i) => {
  fabric.Image.fromURL(src, (image) => {
    const oImage = image.set({
      left: canvas.getWidth() / 2 - 16,
      top: 8 + 40 * i,
      scaleX: 32 / image.width,
      scaleY: 32 / image.height,
      scale: 1,
    });
  
    canvas.add(oImage);
  });
});

body {
  margin: 0;
  height: 100vh;
}

#canvas {
  width: 100%;
  height: 100%;
}

<canvas id="canvas"></canvas>

<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/3.6.3/fabric.min.js"></script>