// ------------------------------------------
// Colorpro 250 Beam size and output calculator
// Copyright High End Systems 1999
// Ver 1.0 MWW 8-17-99
// ------------------------------------------


function validate(a)
{
var c
	if(a.value.length == 0) {
		c = 0.0
	} else {
		c=a.value
		if (c.indexOf("m") != -1) c=c.substring(0,c.length-2)
		if (c.indexOf("ft") != -1) c=c.substring(0,c.length-3)
	}
return c
}


function lightingcalculator(form)
{	
  var Units 			// Metric or English Units
  var Throw			// Throw Distance
  var ImageNarrow		// Image Diameter
  var ImageWide			// Image Diameter
  var OutNarrow			// Output
  var OutWide			// Output
  var LightUnits 		// Temp variable for light units
  var RequiredImage  		// Required Image Size
  var LensFactorNarrow		// Temp variable for Beam angle factor
  var LensFactorWide		// Temp variable for Beam angle factor
  var LensOutputNarrow		// Output at throw of 1 unit (i.e Candelas)
  var LensOutputWide		// Output at throw of 1 unit (i.e Candelas)

	Throw=validate(form.Throw) 
	RequiredImage=validate(form.RequiredImage)

	Units = form.Units.options[form.Units.selectedIndex].value
	
	if (Units == "m") {
		LightUnits = "lux"
	} else { 
		LightUnits = "fc"
	}

	
	LensFactorNarrow = 0.308
	LensOutputNarrow = 173000
	LensFactorWide = 0.669
	LensOutputWide = 81000


	if (Throw != 0 && RequiredImage != 0 ) {
		RequiredImage = 0
	}

	if (Throw ==0 && RequiredImage ==0) {
		Throw = 1 
	}


	if (Throw == 0) {
		Throw = RequiredImage / LensFactorNarrow
		ImageNarrow = RequiredImage
	}

	if (RequiredImage == 0) {
		ImageNarrow = Throw * LensFactorNarrow
	}

	RequiredImage = ImageNarrow
	ImageWide = Throw * LensFactorWide


	if (Throw != 0){
		OutNarrow = LensOutputNarrow / Throw / Throw 
		OutWide = LensOutputWide / Throw / Throw 		

	}

	Throw = Math.round(10 * Throw) / 10
	ImageNarrow = Math.round(10 * ImageNarrow) / 10
	ImageWide = Math.round(10 * ImageWide) / 10
	RequiredImage = Math.round(10 * RequiredImage) / 10
	OutNarrow = Math.round(OutNarrow)
	OutWide = Math.round(OutWide)

	form.Throw.value = "" + Throw + " " + Units
	form.RequiredImage.value = "" + RequiredImage + " " + Units 
	
	form.ImageWide.value = "" + ImageWide + " " + Units 
	form.OutNarrow.value = "" + OutNarrow + " " + LightUnits
	form.OutWide.value = "" + OutWide + " " + LightUnits

}

function clearcalculator(form)
{	
	form.Throw.value = ""
	
	form.OutNarrow.value = ""
	form.OutWide.value = ""
	form.RequiredImage.value = ""
	form.ImageWide.value = ""
}