How to wait for loading images in canvas?

by lindsey.homenick , in category: HTML & CSS , 2 months ago

How to wait for loading images in canvas?

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1 answer

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by mac , a month ago

@lindsey.homenick 

To wait for loading images in a canvas, you can use the onload event handler for each image. Here's a step-by-step guide:

  1. Create a canvas element in your HTML markup:
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<canvas id="myCanvas" width="800" height="400"></canvas>


  1. Get a reference to the canvas element and create a 2D context:
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var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext('2d');


  1. Create an array to store your image objects:
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var images = [];


  1. Initialize and load your images, attaching the onload event handler to each image:
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var image1 = new Image();
image1.src = 'path/to/image1.jpg';
image1.onload = imageLoaded;

var image2 = new Image();
image2.src = 'path/to/image2.jpg';
image2.onload = imageLoaded;

// Add more images as needed

function imageLoaded() {
  images.push(this); // 'this' refers to the loaded image object

  // Check if all images have finished loading
  if (images.length === totalImages) {
    startAnimating(); // Call your function to start drawing or animating on the canvas
  }
}


In the above example, replace 'path/to/image1.jpg' and 'path/to/image2.jpg' with the actual paths to your images. Also, update the totalImages variable with the total number of images you are loading.

  1. After all images have finished loading, you can start rendering or animating on the canvas. Create a function, startAnimating(), to handle this:
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function startAnimating() {
  // Your drawing or animation code here
}


By following these steps, you can ensure that your canvas animations or drawings start only after all images have finished loading.