Math.pi - MACROMEDIA FLASH MX 2004-ACTIONSCRIPT LANGUAGE Reference

Math.PI

Availability
Flash Player 5. In Flash Player 4, the methods and properties of the Math class are emulated using
approximations and might not be as accurate as the non-emulated math functions that Flash
Player 5 supports.
Usage
Math.PI:Number
Parameters
None.
Returns
Nothing.
Description
Constant; a mathematical constant for the ratio of the circumference of a circle to its diameter,
expressed as pi, with a value of 3.141592653589793.
Example
The following example draws a circle using the mathematical constant pi and the Drawing API.
drawCircle(this, 100, 100, 50);
//
function drawCircle(mc:MovieClip, x:Number, y:Number, r:Number):Void {
mc.lineStyle(2, 0xFF0000, 100);
mc.moveTo(x+r, y);
mc.curveTo(r+x, Math.tan(Math.PI/8)*r+y, Math.sin(Math.PI/4)*r+x,
Math.sin(Math.PI/4)*r+y);
mc.curveTo(Math.tan(Math.PI/8)*r+x, r+y, x, r+y);
mc.curveTo(-Math.tan(Math.PI/8)*r+x, r+y, -Math.sin(Math.PI/4)*r+x,
Math.sin(Math.PI/4)*r+y);
mc.curveTo(-r+x, Math.tan(Math.PI/8)*r+y, -r+x, y);
mc.curveTo(-r+x, -Math.tan(Math.PI/8)*r+y, -Math.sin(Math.PI/4)*r+x, -
Math.sin(Math.PI/4)*r+y);
mc.curveTo(-Math.tan(Math.PI/8)*r+x, -r+y, x, -r+y);
mc.curveTo(Math.tan(Math.PI/8)*r+x, -r+y, Math.sin(Math.PI/4)*r+x, -
Math.sin(Math.PI/4)*r+y);
mc.curveTo(r+x, -Math.tan(Math.PI/8)*r+y, r+x, y);
}
438 Chapter 2: ActionScript Language Reference