How to fill the whole canvas with specific color?

javascript html canvas

How to fill the whole HTML5 <canvas> with one color.

I saw some solutions such as this to change the background color using CSS but this is not a good solution since the canvas remains transparent, the only thing that changes is the color of the space it occupies.

Another one is by creating something with the color inside the canvas, for example, a rectangle(see here) but it still does not fill the whole canvas with the color (in case the canvas is bigger than the shape we created).

Is there a solution to fill the whole canvas with a specific color?

Kees de Kooter

Yes, fill in a Rectangle with a solid color across the canvas, use the height and width of the canvas itself:

var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); ctx.fillStyle = "blue"; ctx.fillRect(0, 0, canvas.width, canvas.height); canvas{ border: 1px solid black; }

This helped me immensely! Thanks

ctx.fillStyle="rgb(0,0,255)" fillStyle

nikk wong

If you want to do the background explicitly, you must be certain that you draw behind the current elements on the canvas.

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
// Add behind elements.
ctx.globalCompositeOperation = 'destination-over'
// Now draw!
ctx.fillStyle = "blue";
ctx.fillRect(0, 0, canvas.width, canvas.height);

Thank you for realizing people may not just want a block of color as an image!

This should actually be destination-under, and it should be the first operation on the canvas.

Nanoo

You can change the background of the canvas by doing this:

<head>
    <style>
        canvas {
            background-color: blue;
        }
    </style>
</head>

@Enve said that he or she wanted it to not be using CSS.

Not useful for OP. But perhaps useful for people searching for the question in the title.

Pankaj Bisht

let canvas = document.getElementById('canvas'); canvas.setAttribute('width', window.innerWidth); canvas.setAttribute('height', window.innerHeight); let ctx = canvas.getContext('2d'); //Draw Canvas Fill mode ctx.fillStyle = 'blue'; ctx.fillRect(0,0,canvas.width, canvas.height); * { margin: 0; padding: 0; box-sizing: border-box; } body { overflow: hidden; }

A. West

We don't need to access the canvas context.

Implementing hednek in pure JS you would get canvas.setAttribute('style', 'background-color:#00F8'). But my preferred method requires converting the kabab-case to camelCase.

canvas.style.backgroundColor = '#00F8'

Adding Shapes Dynamically can have problem to show with this approach

Nanoo

You know what, there is an entire library for canvas graphics. It is called p5.js You can add it with just a single line in your head element and an additional sketch.js file.

Do this to your html and body tags first:

<html style="margin:0 ; padding:0">
<body style="margin:0 ; padding:0">

Add this to your head:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.6.1/p5.js"></script>
<script type="text/javascript" src="sketch.js"></script>

The sketch.js file

function setup() {
    createCanvas(windowWidth, windowHeight);
    background(r, g, b);
}

Note that p5.js is 340kB minizied and gzipped! I'd say this page contains some slightly more lightweight options..

@kano I wrote this answer when I was just a noob. It's been a long time since.

How to fill the whole canvas with specific color?

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