/* 
 * PROJECT: NyARToolkitCS
 * --------------------------------------------------------------------------------
 * This work is based on the original ARToolKit developed by
 *   Hirokazu Kato
 *   Mark Billinghurst
 *   HITLab, University of Washington, Seattle
 * http://www.hitl.washington.edu/artoolkit/
 *
 * The NyARToolkitCS is C# edition ARToolKit class library.
 * Copyright (C)2008-2009 Ryo Iizuka
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * For further information please contact.
 *	http://nyatla.jp/nyatoolkit/
 *	<airmail(at)ebony.plala.or.jp> or <nyatla(at)nyatla.jp>
 * 
 */
using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;

namespace jp.nyatla.nyartoolkit.cs.core
{
    public class NyARHistgramAnalyzer_SlidePTile : INyARHistgramAnalyzer_Threshold
    {
        private int _persentage;
        public NyARHistgramAnalyzer_SlidePTile(int i_persentage)
        {
            Debug.Assert(0 <= i_persentage && i_persentage <= 50);
            //初期化
            this._persentage = i_persentage;
        }
        public int getThreshold(NyARHistgram i_histgram)
        {
            //総ピクセル数を計算
            int n = i_histgram.length;
            int sum_of_pixel = i_histgram.total_of_data;
            int[] hist = i_histgram.data;
            // 閾値ピクセル数確定
            int th_pixcels = sum_of_pixel * this._persentage / 100;
            int th_wk;
            int th_w, th_b;

            // 黒点基準
            th_wk = th_pixcels;
            for (th_b = 0; th_b < n - 2; th_b++)
            {
                th_wk -= hist[th_b];
                if (th_wk <= 0)
                {
                    break;
                }
            }
            // 白点基準
            th_wk = th_pixcels;
            for (th_w = n - 1; th_w > 1; th_w--)
            {
                th_wk -= hist[th_w];
                if (th_wk <= 0)
                {
                    break;
                }
            }
            // 閾値の保存
            return (th_w + th_b) / 2;
        }
    }
}
