Draws one or more circles. Will draw outline/fill depending on whether strokeStyle or fillStyle params are present in the drawing options.

// Draw a circle with radius of 10 at 0,0
circle(ctx, {radius:10});

// Draw a circle of radius 10 at 100,100
circle(ctx, {radius: 10, x: 100, y: 100});

// Draw two blue outlined circles
circle(ctx, [ {radius: 5}, {radius: 10} ], {strokeStyle:`blue`});