 
         _pixelSize[0] = value;
         _pixelSize[2] = value / 2;
-        _paramsDirty = true;
+        _offsetsDirty = true;
     }
 
     public function get pixelHeight():Number { return _pixelSize[1]; }

        // shader. By making use of linear texture sampling, we can produce similar output
        // to what would be 9 lookups.

        _paramsDirty = false;

        var multiplier:Number, str:Number = _strengths[_pass];
        var i:int, count:int = 4;


    protected static const TEXTURE_FLAGS:Array = [TextureFlag.TYPE_2D, TextureFlag.MODE_CLAMP, TextureFlag.FILTER_LINEAR, TextureFlag.MIP_NO];

    protected static var _verticalOffsets:Vector.<Number>     = new <Number>[0.0, 1.3846153846, 0.0, 3.2307692308];
    protected static var _horizontalOffsets:Vector.<Number>   = new <Number>[1.3846153846, 0.0, 3.2307692308, 0.0];
    protected static var _weights:Vector.<Number>             = new <Number>[0.2270270270, 0.3162162162, 0.0702702703, 0];

    private var _type:String                    = HORIZONTAL;
    private var _pass:int                       = 0;
    private var _strength:Number                = Number.NaN;
    private var _firstPassStrength:Number       = DEFAULT_FIRST_PASS_STRENGTH;
    private var _strengthIncreaseRatio:Number   = DEFAULT_STRENGTH_INCREASE_PER_PASS_RATIO;

    private var _uv:Vector.<Number>             = new <Number>[0, 1, 0, 1];
    private var _pixelSize:Vector.<Number>      = new <Number>[Number.NaN, Number.NaN, Number.NaN, Number.NaN];

    protected var _offsetsDirty:Boolean         = true;
    protected var _strengthsDirty:Boolean       = true;

    protected var _offsets:Vector.<Number>      = new <Number>[0, 0, 0, 0];
    protected var _strengths:Vector.<Number>    = new <Number>[];

    // shader constants
    protected var uvCenter:IRegister            = VARYING[0];
