/**
 * MyPanel.java
 * 
 * 該類顯示兩個(gè)圖片：濾波前和濾波后的圖片
 * 用函數(shù)WFilter來(lái)對(duì)圖片進(jìn)行濾波處理
 * 由于JAVA的Image類不直接支持bmp位圖，所以要自己編寫(xiě)代碼來(lái)顯示位圖
 *
 * Copyright 2004 by 海南大學(xué)信息學(xué)院
 * @author 溫小斌
 * @version 1.0
 */

import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import javax.swing.*;
import java.awt.color.*;

public class MyPanel extends JPanel
{
	BufferedImage image;

	FileInputStream fs;
	int bflen=14; // 14 字節(jié) BitmapFileHeader
	byte bf[]=new byte[bflen];
	int bilen=40; // 40 字節(jié) BitmapInfoHeader
	byte bi[]=new byte[bilen];
	int nsize;
	int nbisize;
	int nwidth;
	int nheight;
	int nplanes;//位面數(shù)總為1
	int nbitcount;//比特?cái)?shù)/象素
	int ncompression;//壓縮數(shù)據(jù)
	int nsizeimage;
	int nxpm;
	int nypm;
	int nclrused;//使用的顏色索引
	int nclrimp;//重要顏色索引
	int nNumColors = 0;
	int npalette[];
	byte bpalette[];//調(diào)色板范圍
	int npad8;
	int ndata8[];
	byte bdata[];

	protected void paintComponent(Graphics g)  //重畫(huà)，刷新
	{
		super.paintComponent(g);
		if (image != null)
			g.drawImage(image, 0, 0, null);
	}

   public void loadImage(String name, boolean filter, float a, float q, float c, float r) //參數(shù)name表示文件名，filter表示是否濾波
   {  
	   // 調(diào)用圖像,在這之前需要先調(diào)用自定義的loadBitmap函數(shù)，這是因?yàn)镴AVA不直接支持bmp位圖
      Image loadedImage
         = loadBitmap(name, filter, a, q, c, r);
      MediaTracker tracker = new MediaTracker(this);
      tracker.addImage(loadedImage, 0);
      try { tracker.waitForID(0); }
      catch (InterruptedException e) {}
      //調(diào)入圖像緩沖
      image = new BufferedImage(loadedImage.getWidth(null), loadedImage.getHeight(null), BufferedImage.TYPE_INT_BGR);
      Graphics2D g2 = image.createGraphics();
      g2.drawImage(loadedImage, 0, 0, null);
      repaint();  //調(diào)用paintComponent刷新窗口
   }

   public Image loadBitmap(String name, boolean filter, float a, float q, float c, float r)
	{
	   Image bitmap;

	   try{
			fs=new FileInputStream(name);
			fs.read(bf,0,bflen);
			fs.read(bi,0,bilen);

			//解釋數(shù)據(jù)
			nsize = (((int)bf[5]&0xff)<<24) | (((int)bf[4]&0xff)<<16) | (((int)bf[3]&0xff)<<8) | (int)bf[2]&0xff;
			nbisize = (((int)bi[3]&0xff)<<24) | (((int)bi[2]&0xff)<<16) | (((int)bi[1]&0xff)<<8) | (int)bi[0]&0xff;
			nwidth = (((int)bi[7]&0xff)<<24) | (((int)bi[6]&0xff)<<16) | (((int)bi[5]&0xff)<<8) | (int)bi[4]&0xff;
			nheight = (((int)bi[11]&0xff)<<24) | (((int)bi[10]&0xff)<<16) | (((int)bi[9]&0xff)<<8) | (int)bi[8]&0xff;
			nplanes = (((int)bi[13]&0xff)<<8) | (int)bi[12]&0xff;
			nbitcount = (((int)bi[15]&0xff)<<8) | (int)bi[14]&0xff;
			ncompression = (((int)bi[19])<<24) | (((int)bi[18])<<16) | (((int)bi[17])<<8) | (int)bi[16];
			nsizeimage = (((int)bi[23]&0xff)<<24) | (((int)bi[22]&0xff)<<16) | (((int)bi[21]&0xff)<<8) | (int)bi[20]&0xff;
			nxpm = (((int)bi[27]&0xff)<<24) | (((int)bi[26]&0xff)<<16) | (((int)bi[25]&0xff)<<8) | (int)bi[24]&0xff;
			nypm = (((int)bi[31]&0xff)<<24) | (((int)bi[30]&0xff)<<16) | (((int)bi[29]&0xff)<<8) | (int)bi[28]&0xff;
			nclrused = (((int)bi[35]&0xff)<<24) | (((int)bi[34]&0xff)<<16) | (((int)bi[33]&0xff)<<8) | (int)bi[32]&0xff;
			nclrimp = (((int)bi[39]&0xff)<<24) | (((int)bi[38]&0xff)<<16) | (((int)bi[37]&0xff)<<8) | (int)bi[36]&0xff;
			if (nbitcount == 8)  //如果是256色位圖
		   {
				if (nclrused > 0)//clrused 為0表示使用所有調(diào)色板項(xiàng)
					nNumColors = nclrused;
				else
					nNumColors = (1&0xff)<<nbitcount;
				
				// 讀取調(diào)色板顏色。
				npalette = new int [nNumColors];
				bpalette = new byte [nNumColors*4];
				fs.read (bpalette, 0, nNumColors*4);
				int nindex8 = 0;
				for (int n = 0; n < nNumColors; n++)
				{
					npalette[n] = (255&0xff)<<24 | (((int)bpalette[nindex8+2]&0xff)<<16) | (((int)bpalette[nindex8+1]&0xff)<<8) | (int)bpalette[nindex8]&0xff;
					nindex8 += 4;
				}
				
				// 讀取圖像數(shù)據(jù)（實(shí)際上是調(diào)色板的索引）
				// 掃描行仍被補(bǔ)足到 4 個(gè)字節(jié)。
				npad8 = (nsizeimage / nheight) - nwidth;
				ndata8 = new int [nwidth*nheight];
				bdata = new byte [(nwidth+npad8)*nheight];
				fs.read (bdata, 0, (nwidth+npad8)*nheight);
				nindex8 = 0;
				for (int j8 = 0; j8 < nheight; j8++)
				{
					for (int i8 = 0; i8 < nwidth; i8++)
					{
						if(filter)  //如果需要濾波，調(diào)用濾波函數(shù)WFilter
						{
							ndata8 [nwidth*(nheight-j8-1)+i8] = npalette [(WFilter(nindex8, a, q, c, r)&0xff)];
							nindex8++;
						}
						else  //如果不需要濾波
						{
							ndata8 [nwidth*(nheight-j8-1)+i8] = npalette [((int)bdata[nindex8]&0xff)];
							nindex8++;
						}
					}
					nindex8 += npad8;
				}
				bitmap = createImage(new MemoryImageSource(nwidth, nheight, ndata8, 0, nwidth));  //產(chǎn)生Image的對(duì)象bitmap
		   }
		   else
		   {
			   return (Image)null;
		   }
		   fs.close();
		   return bitmap;
		}
		catch(Exception e){
			System.err.println(e);
			return (Image)null;
		}
	}

	//維納濾波函數(shù)
	public int WFilter(int n, float a, float q, float c, float r)
	{
		// x 為濾波器的輸入信號(hào)
		float p;
		float p1, p2, p3, p4, p5;
		float g;
		float f;
		 //濾波器的沖激響應(yīng)
		int j;
		int s[]; //濾波器的輸出信號(hào)

		p1 = (a*a-1)*r;
		p2 = c*c*q;
		p3 = (a*a-1)*(a*a-1)*r*r;
		p4 = 2*c*c*r*q*(1+a*a);
		p5 = c*c*c*c*q*q;
		p = (float)((p1+p2+Math.sqrt(p3+p4+p5))/(2*a));

		g = (c*p)/(r+c*c*p);
		f = a*(1-c*g);

		/*
		for(int i=0; i<=n; i++)
		{
			s += g*(float)Math.pow(f, n)*bdata[n-i];
		}
		*/
		if(j=0)
		{
			s[j]=g*bdata[0];
		return Math.round(s);
	    }
		else
	   {
		for(int i=1;i<=n;i++)
		{j=i;
			s[j]=f*s[j-1]+g*bdata[i]

		/*s=g*f*bdata[n];*/
		
		return Math.round(s);
		}
	   }

	}
}