package net.scratchbrain.color
{
	import net.scratchbrain.color.AverageColor;
	public class AverageColor
	{
		
		public static function averageHex(_hex1:uint,_hex2:uint):uint
		{
			var rgb1:Object = ConvertColor.HexToRGB(_hex1);
			var rgb2:Object = ConvertColor.HexToRGB(_hex2);
			var hsb1:Object = ConvertColor.RGBToHSB(rgb1.r, rgb1.g, rgb1.b);
			var hsb2:Object = ConvertColor.RGBToHSB(rgb2.r, rgb2.g, rgb2.b);
			return averageHsb(hsb1.h, hsb1.s, hsb1.b, hsb2.h, hsb2.s, hsb2.b);
			
		}
		public static function averageRgb(_r1:int,_g1:int,_b1:int,_r2:int,_g2:int,_b2:int):uint
		{
			var hsb1:Object = ConvertColor.RGBToHSB(_r1, _g1, _b1);
			var hsb2:Object = ConvertColor.RGBToHSB(_r2, _g2, _b2);
			return averageHsb(hsb1.h, hsb1.s, hsb1.b, hsb2.h, hsb2.s, hsb2.b);
		}
		public static function averageHsb(_h1:int, _s1:int, _b1:int, _h2:int, _s2:int, _b2:int):uint
		{
			var _h:int;
			var _s:int;
			var _b:int;
			
			if(_h1 <= 18 && _s1 != 0 && _h2 >= 180){
				_h1 = 360;
			}
			if(_h2 <= 18 && _s2 != 0 && _h1 >= 180){
				_h2 = 360;
			}
			
			if(_s1 != 0 && _s2 != 0){
				_h = (_h1 + _h2)/2;
				_s = (_s1 + _s2)/2;
				_b = (_b1 + _b2)/2;
			}else if(_s1 == 0 && _s2 == 0){
				_h = 0;
				_s = 0;
				_b = (_b1 + _b2)/2;
			}else{
				_h = (_h1 != 0) ? _h1 : _h2;
				_s = (_s1 + _s2)/2;
				_b = (_b1 + _b2)/2;
			}
			
			var rgb:Object = ConvertColor.HSBToRGB(_h, _s, _b);
			return ConvertColor.RGBToHex(rgb.r, rgb.g, rgb.b);
		}
	}
}


package net.scratchbrain.color
{
	public class ConvertColor
	{

		public static function RGBToHex(r:int,g:int,b:int):uint
		{
			var hex:uint = r<<16 | g<<8 | b;
			return hex;
		}

		public static function HexToRGB(value:uint):Object{
			var rgb:Object = new Object();
			rgb.r = (value >> 16) & 0xFF
			rgb.g = (value >> 8) & 0xFF
			rgb.b = value & 0xFF			
			return rgb;
		}

		public static function RGBToHSB(r:int,g:int,b:int):Object{
			var hsb:Object = new Object;
			var _max:Number = Math.max(r,g,b);
			var _min:Number = Math.min(r,g,b);
			
			hsb.s = (_max != 0) ? (_max - _min) / _max * 100: 0;

			hsb.b = _max / 255 * 100;

			if(hsb.s == 0){
				hsb.h = 0;
			}else{
				switch(_max)
				{
					case r:
						hsb.h = (g - b)/(_max - _min)*60 + 0;
						break;
					case g:
						hsb.h = (b - r)/(_max - _min)*60 + 120;
						break;
					case b:
						hsb.h = (r - g)/(_max - _min)*60 + 240;
						break;
				}
			}
			
			hsb.h = Math.min(360, Math.max(0, Math.round(hsb.h)))
			hsb.s = Math.min(100, Math.max(0, Math.round(hsb.s)))
			hsb.b = Math.min(100, Math.max(0, Math.round(hsb.b)))
			
			return hsb;
		}

		public static function HSBToRGB(h:int,s:int,b:int):Object{
			var rgb:Object = new Object();
		
			var max:Number = (b*0.01)*255;
			var min:Number = max*(1-(s*0.01));
			
			if(h == 360){
				h = 0;
			}
			
			if(s == 0){
				rgb.r = rgb.g = rgb.b = b*(255*0.01) ;
			}else{
				var _h:Number = Math.floor(h / 60);
				
				switch(_h){
					case 0:
						rgb.r = max	;
						rgb.g = min+h * (max-min)/ 60;
						rgb.b = min;
						break;
					case 1:
						rgb.r = max-(h-60) * (max-min)/60;
						rgb.g = max;
						rgb.b = min;
						break;
					case 2:
						rgb.r = min ;
						rgb.g = max;
						rgb.b = min+(h-120) * (max-min)/60;
						break;
					case 3:
						rgb.r = min;
						rgb.g = max-(h-180) * (max-min)/60;
						rgb.b =max;
						break;
					case 4:
						rgb.r = min+(h-240) * (max-min)/60;
						rgb.g = min;
						rgb.b = max;
						break;
					case 5:
						rgb.r = max;
						rgb.g = min;
						rgb.b = max-(h-300) * (max-min)/60;
						break;
					case 6:
						rgb.r = max;
						rgb.g = min+h  * (max-min)/ 60;
						rgb.b = min;
						break;
				}
		
				rgb.r = Math.min(255, Math.max(0, Math.round(rgb.r)))
				rgb.g = Math.min(255, Math.max(0, Math.round(rgb.g)))
				rgb.b = Math.min(255, Math.max(0, Math.round(rgb.b)))
			}
			return rgb;
		}
	}
}

http://www.libspark.org/wiki/scratchbrain/AverageColor

Full credit for this code goes to Scratchbrain (http://www.scratchbrain.net/blog/ver2/)

AS3 Average Colour Between Two Colours

color

ActionScript 3