CFLib.org – Common Function Library Project

Description:
Calculates whether the point pointX,pointY lies in or on the circumfrence of the circle at centre circleX,circleY of radius circleRadius.

Return Values:
Returns a boolean.

Example:

<cfif isPointInCircle(10, 10, 15, 15, 5)>
    <cfoutput>Point is in circle</cfoutput>
<cfelse>
    <cfoutput>Point is NOT in circle.</cfoutput>
</cfif>

Parameters:

Full UDF Source:

/**
 * Determines if a point lies within a circle.
 * 
 * @param pointX      X value of point. (Required)
 * @param pointY      Y value of point. (Required)
 * @param circleX      X value of center of circle. (Required)
 * @param circleY      Y value of center of circle. (Required)
 * @param circleRadius      Radius of circle. (Required)
 * @return Returns a boolean. 
 * @author Keith Westcott (kaw4@york.ac.uk) 
 * @version 1, April 20, 2006 
 */
function isPointInCircle (pointX, pointY, circleX, circleY, circleRadius) {
    var dx = (circleX - pointX);
    var dy = (circleY - pointY);
    return (dx * dx + dy * dy) LTE circleRadius * circleRadius;
}