//TarrantIT 2005
function SetCalc()
{	
	CalcCentersCircle();
}
var desc = "";
function CheckRange(ctrl, min, max)
{
	if (ctrl.value == "")
	{
		alert('Value Required');
		ctrl.select();
		return false;
	}
	var val = parseFloat(ctrl.value);
	if (isNaN(val))
	{
		ctrl.focus();
		alert('Numbers Only');
		ctrl.select();
		return false;
	}
	else if (val < min)
	{
		ctrl.focus();
		alert('Must be larger than or = '+ min);
		ctrl.select();
		return false;
	}
	else if (val > max)
	{				
		ctrl.focus();
		alert('Must be smaller than or = '+ max);
		ctrl.select();
		return false;
	}
	return true;
}
var rad = 180 / Math.PI;
function CalcCentersCircle()
{
    var radius = parseInt(document.getElementById("ddCRadius_Feet").value) * 384 + parseInt(document.getElementById("ddCRadius_Inches").value) * 32 + parseInt(document.getElementById("ddCRadius_Frac").value);
    var ctrl = document.getElementById("txtCCMembers");
    if (! CheckRange(ctrl, 2, 1000))
        return;
    var members = ctrl.value;
    var di = radius * 2;
    var circ = Math.PI * di;
    var centersRound = circ / members;
    var memberAngle = 360 / members;
    var rangle = (memberAngle / 2) / rad;
    var centersStraight = (radius * Math.sin(rangle)) * 2;
    var useFeet = document.getElementById("rbUseFeetC").checked;
    document.getElementById("spnCentersCircle").innerHTML = ConEng(Math.round(centersRound), useFeet);
    document.getElementById("spnCentersCircleStraight").innerHTML = ConEng(Math.round(centersStraight), useFeet);
    document.getElementById("spnCCCircumference").innerHTML = ConEng(Math.round(circ), useFeet);
    var res = "";
    var run = 0.0;
    for (var i=0; i < members; i++)
    {
        run += centersRound;
        res += ConEng(Math.round(run), useFeet) +", ";
    }
    res = res.substring(0, res.length - 2);
    document.getElementById("spnRunningCircle").innerHTML = "Run around Circumference ~ "+ res;
    document.images["imgCentersCircle"].title = "With "+ members +" members in a circle of radius "+ ConEng(radius, useFeet) +", centers around circumference = "+ ConEng(centersRound, useFeet) +" and centers straight across between members = "+ ConEng(centersStraight, useFeet);
}