ppi calc

ppi-calc

var TO_MILIMETER = 25.4
function calc_dpi (widthPixels: number, heightPixels: number, diagonal: float) {
	var x = width
	var y = height
	var ratio = y/x;
	var xd = Math.sqrt( Math.pow(diagonal,2) / ( 1 + Math.pow(ratio, 2) ));
	var yd = xd * ratio;
	var pitch = TO_MILIMETER/(x/xd);
	var result = {
		displayDiagonalCentimeters : diagonal * 2.54,
		displayWidth : xd,
		displayHeight : yd,
		displayAreaSquareInches  : xd*yd,
		displayWidthCentimeters : 2.54*xd,
		displayHeightCentimeters : 2.54*yd,
		displayAreaSquareCentimeters : xd*yd * 2.54*2.54,
		ppiWidth : x/xd,
		ppiHeight : y/yd,
		pixelPixelDistanceMilimeters : pitch,
		ppiSquare : x/xd*y/yd
	};
	return result;
}