Draw a circle in a cavas html element using the arc method.
An arc drawn to the HTML5 canvas.
javascript
ctx.arc(canvas.width / 2, canvas.height / 2, 100, 0, Math.PI * 2, false);
ctx.strokeStyle = "blue";
ctx.stroke();
The arc canvas API method takes five (or optionally 6) arguments.
JavaScript
arc( x, y, r, sAngle, eAngle )
x
The x-coordinate of the center of the circle, y
The y-coordinate of the center of the circle, r
The radius of the circle, sAngle
The starting angle, in radians (0 is at the 3 o’clock position of the arc’s circle), eAngle
The ending angle.
Note that the start / end angle of the arc is expressed in radians. That is why the end angle is 2*PI
. 2*PI
is equivalent to 360 degrees.
Here is a link to the HTML and JavaScript for this app. View page source to see the code.