How to Implement Scrolling on a Large HTML Canvas?

How can I implement scrolling on a large HTML canvas for better navigation?

<canvas id='myCanvas' width='1000' height='1000'></canvas>

Implementing scrolling on a large HTML canvas allows users to navigate through more content than what can fit on the screen at once. This can enhance user interaction and improve the usability of applications such as games, simulations, or data visualizations.

const canvas = document.getElementById('myCanvas');
const ctx = canvas.getContext('2d');
c = 0;

draw();

function draw() {
    // Clear the canvas
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    // Draw something to represent large content
    ctx.fillStyle = 'blue';
    ctx.fillRect(c, 0, 100, 100);
    c += 5;
    if (c < canvas.width) {
        requestAnimationFrame(draw);
    }
}

Causes

• The canvas size is larger than the viewport, resulting in only a portion being visible.
• Users require the ability to access parts of the canvas that are out of view.

Solutions

• Use HTML and CSS to set a fixed size for the canvas container while allowing overflow scrolling.
• Employ JavaScript to manage the canvas's drawing context, thereby adjusting the visible portion based on user input or scrolling events.

Mistake: Not setting the canvas size correctly, leading to unexpected results.

Solution: Always define both the width and height attributes on the canvas element.

Mistake: Forgetting to clear the canvas before redrawing, which may cause visual artifacts.

Solution: Use the clearRect method to clear the canvas before each draw.