package flare.vis.operator.encoder
{
    import flare.scale.ScaleType;
    import flare.util.palette.Palette;
    import flare.util.palette.SizePalette;
    import flare.vis.data.Data;
    
    /**
     * Encodes a data field into size values, using a scale transform and a
     * size palette to determines an item's scale. The target property of a
     * SizeEncoder is assumed to be the <code>DataSprite.size</code> property.
     */
    public class SizeEncoder extends Encoder
    {
        private var _palette:SizePalette;
        
        /** @inheritDoc */
        public override function get palette():Palette { return _palette; }
        public override function set palette(p:Palette):void {
            _palette = p as SizePalette;
        }
        /** The palette as a SizePalette instance. */
        public function get sizes():SizePalette { return _palette; }
        
        // --------------------------------------------------------------------
        
        /**
         * Creates a new SizeEncoder. By default, the scale type is set to
         * a quantile scale grouped into 5 bins. Adjust the values of the
         * <code>scale</code> property to change these defaults.
         * @param source the source property
         * @param group the data group to process
         * @param palette the size palette to use. If null, a default size
         *  palette will be used.
         */
        public function SizeEncoder(source:String=null,
            group:String=Data.NODES, palette:SizePalette=null)
        {
            super(source, "size", group);
            _binding.scaleType = ScaleType.QUANTILE;
            _binding.bins = 5;
            if (palette) {
                _palette = palette;
            } else {
                _palette = new SizePalette();
                _palette.is2D = (group != Data.EDGES);
            }
        }
        
        /** @inheritDoc */
        protected override function encode(val:Object):*
        {
            return _palette.getSize(_binding.interpolate(val));
        }
        
    } // end of class SizeEncoder
}