Canvas Draw Arc

Posted in Canvas Tutorial

Updated on Oct 13, 2024

By Mari Selvan

👁️ 97 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

When it comes to drawing graphics dynamically on web pages, the HTML5 <canvas> element provides a powerful toolset for developers. One of the fundamental shapes that can be drawn on the canvas is an arc, which is a portion of the circumference of a circle.

In this guide, we'll explore how to use the Canvas API to draw arcs programmatically.

💡 Syntax

To draw an arc on a canvas, you'll use the arc() method of the CanvasRenderingContext2D interface. Here's the basic syntax:

Syntax

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context.arc(x, y, radius, startAngle, endAngle, anticlockwise);

🧰 Attributes

x: The x-coordinate of the center of the arc.
y: The y-coordinate of the center of the arc.
radius: The radius of the arc.
startAngle: The starting angle (in radians) where the arc begins.
endAngle: The ending angle (in radians) where the arc ends.
anticlockwise: Optional. Specifies whether the arc should be drawn in the anticlockwise direction (default is false).

📄 Example

Let's draw a simple arc on a canvas:

index.html

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<canvas id="myCanvas" width="200" height="200"></canvas>
<script>
  const canvas = document.getElementById('myCanvas');
  const context = canvas.getContext('2d');

  // Draw a red arc
  context.beginPath();
  context.arc(100, 100, 50, 0, Math.PI, false); // Draws a semicircle
  context.strokeStyle = 'red';
  context.lineWidth = 2;
  context.stroke();
</script>

🧠 How it works?

In this example, we've drawn a semicircle centered at (100, 100) with a radius of 50 units. The arc starts from the rightmost point (0 radians) and ends at the leftmost point (Math.PI radians), forming a red semicircular arc.

🎉 Conclusion

Drawing arcs on a canvas opens up a world of possibilities for creating complex shapes and visual effects in web applications.

By mastering the arc() method and understanding its parameters, you can dynamically generate arcs of varying sizes and styles to enhance the interactivity and aesthetics of your projects.