How to prevent compositing with an html canvas?
How to prevent compositing with an html canvas?
1 answer
@filiberto
One way to prevent compositing with an HTML canvas is by setting the globalCompositeOperation property to source-over. This property determines how shapes and images are drawn onto the canvas and if it is set to source-over, the new shapes will be painted over the existing content.
You can also use clearRect method to clear the entire canvas or a specific portion of it before drawing new content, this way you can prevent compositing with the existing content.
Here is an example code snippet to prevent compositing with an HTML canvas:
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<!DOCTYPE html>
<html>
<head>
<title>Preventing Compositing with HTML Canvas</title>
</head>
<body>
<canvas id="myCanvas" width="200" height="200"></canvas>
<script>
const canvas = document.getElementById('myCanvas');
const ctx = canvas.getContext('2d');
// Set globalCompositeOperation to source-over
ctx.globalCompositeOperation = 'source-over';
// Clear the canvas before drawing new content
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Draw a rectangle on the canvas
ctx.fillStyle = 'green';
ctx.fillRect(50, 50, 100, 100);
</script>
</body>
</html>
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By setting the globalCompositeOperation to source-over and clearing the canvas before drawing new content, you can prevent compositing with the existing content on the canvas.