本文章完成的是讀入bmp圖片、將資料存入矩陣/TXT檔案、儲存圖片的功能。

在開始之前，我們需要了解bmp點陣圖的儲存方式:

BMP檔案的資料按照從檔案頭開始的先後順序分為四個部分：（1）bmp檔案頭(bmp file header)：提供檔案的格式、大小等資訊（2）點陣圖資訊頭(bitmap information)：提供影象資料的尺寸、位平面數、壓縮方式、顏色索引等資訊（3）調色盤(color palette)：可選，如使用索引來表示影象，調色盤就是索引與其對應的顏色的對映表

（4）點陣圖資料(bitmap data)：影象資料,畫素按照從下到上、從左到右的順序每行佔用的空間必須是4的整數倍

read_save.h

#include<fstream>
#include<windows.h>
#include<iostream>
using namespace std;
unsigned char *pBmpBuf;//讀入影象資料的指標
int bmpWidth;//影象的寬
int bmpHeight;//影象的高
RGBQUAD *pColorTable;//顏色表指標
int biBitCount;//影象型別，每畫素位數
//顯示點陣圖檔案頭資訊   
void showBmpHead(BITMAPFILEHEADER pBmpHead){
	cout << "\n點陣圖檔案頭:" << endl
 
;
	cout << "檔案大小:" << pBmpHead.bfSize << endl; 
	cout << "保留字_1:" << pBmpHead.bfReserved1 << endl;
	cout << "保留字_2:" << pBmpHead.bfReserved2 << endl;
	cout << "實際點陣圖資料的偏移位元組數:" << pBmpHead.bfOffBits << endl << endl;
}
//顯示點陣圖資訊頭資訊  
 
void showBmpInforHead(BITMAPINFOHEADER pBmpInforHead){
	cout << "\n點陣圖資訊頭:" << endl;
	cout << "結構體的長度:" << pBmpInforHead.biSize << endl;
	cout << "點陣圖寬:" << pBmpInforHead.biWidth << endl;
	cout << "點陣圖高:" << pBmpInforHead.biHeight << endl;
	cout << "biPlanes平面數:" << pBmpInforHead.biPlanes << endl;
	cout << "biBitCount採用顏色位數:" << pBmpInforHead.biBitCount << endl;
	cout << "壓縮方式:" << pBmpInforHead.biCompression << endl;
	cout << "biSizeImage實際點陣圖資料佔用的位元組數:" << pBmpInforHead.biSizeImage << endl;
	cout << "X方向解析度:" << pBmpInforHead.biXPelsPerMeter << endl;
	cout << "Y方向解析度:" << pBmpInforHead.biYPelsPerMeter << endl;
	cout << "使用的顏色數:" << pBmpInforHead.biClrUsed << endl;
	cout << "重要顏色數:" << pBmpInforHead.biClrImportant << endl;
}
//-----------------------------------------------------------------------------------------
//給定一個影象點陣圖資料、寬、高、顏色表指標及每畫素所佔的位數等資訊,將其寫到指定檔案中
bool readBmp(char *bmpName)
{
	FILE *fp = fopen(bmpName, "rb");//二進位制讀方式開啟指定的影象檔案
	if (fp == 0)
		return 0;
	//跳過點陣圖檔案頭結構BITMAPFILEHEADER
	fseek(fp, sizeof(BITMAPFILEHEADER), 0);
	/*
	BITMAPFILEHEADER filehead;
	fread(&filehead, 1, sizeof(BITMAPFILEHEADER), fp);
	showBmpHead(filehead);//顯示檔案頭   
*/
	//定義點陣圖資訊頭結構變數，讀取點陣圖資訊頭進記憶體，存放在變數head中
	BITMAPINFOHEADER infohead;
	fread(&infohead, sizeof(BITMAPINFOHEADER), 1, fp); //獲取影象寬、高、每畫素所佔位數等資訊
	bmpWidth = infohead.biWidth;
	bmpHeight = infohead.biHeight;
	biBitCount = infohead.biBitCount;//定義變數，計算影象每行畫素所佔的位元組數（必須是4的倍數）
	showBmpInforHead(infohead);//顯示資訊頭 
	int lineByte = (bmpWidth * biBitCount / 8 + 3) / 4 * 4;//灰度影象有顏色表，且顏色表表項為256
	if (biBitCount == 8)
	{
		//申請顏色表所需要的空間，讀顏色表進記憶體
		pColorTable = new RGBQUAD[256];
		fread(pColorTable, sizeof(RGBQUAD), 256, fp);
	}
	//申請點陣圖資料所需要的空間，讀點陣圖資料進記憶體
	pBmpBuf = new unsigned char[lineByte * bmpHeight];
	fread(pBmpBuf, 1, lineByte * bmpHeight, fp);
	fclose(fp);//關閉檔案
	return 1;//讀取檔案成功
}
//儲存圖片
bool saveBmp(char *bmpName, unsigned char *imgBuf, int width, int height, int biBitCount, RGBQUAD *pColorTable)
{
	//如果點陣圖資料指標為0，則沒有資料傳入，函式返回
	if (!imgBuf)
		return 0;
	//顏色表大小，以位元組為單位，灰度影象顏色表為1024位元組，彩色影象顏色表大小為0
	int colorTablesize = 0;
	if (biBitCount == 8)
		colorTablesize = 1024;
	//待儲存影象資料每行位元組數為4的倍數
	int lineByte = (width * biBitCount / 8 + 3) / 4 * 4;
	//以二進位制寫的方式開啟檔案
	FILE *fp = fopen(bmpName, "wb");
	if (fp == 0)
		return 0;
//------------------------------------------------------------------------------------------------------------------
	//申請點陣圖檔案頭結構變數，填寫檔案頭資訊
	BITMAPFILEHEADER fileHead;
	fileHead.bfType = 0x4D42;//bmp型別
	//bfSize是影象檔案4個組成部分之和
	fileHead.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + colorTablesize + lineByte*height;
	fileHead.bfReserved1 = 0;
	fileHead.bfReserved2 = 0;
	//bfOffBits是影象檔案前3個部分所需空間之和
	fileHead.bfOffBits = 54 + colorTablesize;
//--------------------------------------------------------------------------------------------------------------------
	//寫檔案頭進檔案
	fwrite(&fileHead, sizeof(BITMAPFILEHEADER), 1, fp);
	//申請點陣圖資訊頭結構變數，填寫資訊頭資訊
	BITMAPINFOHEADER infohead;
	infohead.biBitCount = biBitCount;
	infohead.biClrImportant = 0;
	infohead.biClrUsed = 0;
	infohead.biCompression = 0;
	infohead.biHeight = height;
	infohead.biPlanes = 1;
	infohead.biSize = 40;
	infohead.biSizeImage = lineByte*height;
	infohead.biWidth = width;
	infohead.biXPelsPerMeter = 0;
	infohead.biYPelsPerMeter = 0;
	//寫點陣圖資訊頭進記憶體
	fwrite(&infohead, sizeof(BITMAPINFOHEADER), 1, fp);
//----------------------------------------------------------------------------------------------------------------------
	//如果灰度影象，有顏色表，寫入檔案 
	if (biBitCount == 8)
		fwrite(pColorTable, sizeof(RGBQUAD), 256, fp);
	//寫點陣圖資料進檔案
	fwrite(imgBuf, height*lineByte, 1, fp);
	//關閉檔案
	fclose(fp);
	return 1;
}

read.cpp

#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<iomanip>
#include"readbmp.h"
#include"savebmp.h"
using namespace std;
//unsigned int out_r[2000][2000];
//unsigned int out_g[2000][2000];
//unsigned int out_b[2000][2000];
unsigned int **out_r;
unsigned int **out_g;
unsigned int **out_b;
void doIt()
{
	char readPath[] = "D:\\C++_file\\image_deal_C++\\read_BMP\\lunpan.bmp";
	readBmp(readPath);
	// 輸出整體影象資訊
	cout << "\nwidth=" << bmpWidth << "\nheight=" << bmpHeight << "\nbiBitCount=" << biBitCount << endl;
	// 影象的位元組數
	int linebyte1 = (bmpWidth*biBitCount / 8 + 3) / 4 * 4;
	int n = 0, m = 0, count_xiang_su = 0;
	out_r = new unsigned int *[bmpHeight];        //開闢指標陣列
	for (int i = 0; i<bmpHeight; i++)
		out_r[i] = new unsigned int[bmpWidth];
	out_g = new unsigned int *[bmpHeight];        //開闢指標陣列
	for (int i = 0; i<bmpHeight; i++)
		out_g[i] = new unsigned int[bmpWidth];
	out_b = new unsigned int *[bmpHeight];        //開闢指標陣列
	for (int i = 0; i<bmpHeight; i++)
		out_b[i] = new unsigned int[bmpWidth];
	//初始化原始畫素的陣列。
	if (biBitCount == 8)
	{
		for (int i = 0; i<bmpHeight / 2; i++)
		{
			for (int j = 0; j<bmpWidth / 2; i++)
				*(pBmpBuf + i*linebyte1 + j) = 0;
		}
	}
	if (biBitCount == 24)
	{
		for (int i = 0; i<bmpHeight; i++)
		{
			for (int j = 0; j<bmpWidth; j++)
			{
				for (int k = 0; k<3; k++)//每畫素RGB三個分量分別置0才變成黑色
				{
					m = *(pBmpBuf + i*linebyte1 + j * 3 + k);
					count_xiang_su++;
				}
				n++;
			}
		}
		cout << "總的畫素個素為:" << n << endl;
		cout << "----------------------------------------------------" << endl;
	}
	if (biBitCount == 24)
	{
		for (int i = 0; i<bmpHeight; i++)
		{
			for (int j = 0; j<bmpWidth; j++)
			{
				out_r[bmpHeight - 1 - i][j] = pBmpBuf[j * 3 + 2 + bmpWidth*i * 3];
				out_g[bmpHeight - 1 - i][j] = pBmpBuf[j * 3 + 1 + bmpWidth *i * 3];
				out_b[bmpHeight - 1 - i][j] = pBmpBuf[j * 3 + bmpWidth *i * 3];
			}
		}
		//	for (int i = 0; i<bmpHeight; i++)
		//	{
		//		for (int j = 0; j<bmpWidth; j++)
		//		{
		//			cout<<out_r[i][j]<<endl;
		//			cout << out_g[i][j] << endl;
		//			cout << out_b[i][j] << endl;
		//		}
		//	}
	}
	//---------------------------------------------------------------------------------------
	/*//將畫素資料存入TXT檔案。
	ofstream outfile;
	outfile.open("rrbmp.txt", ios::in | ios::trunc);
	if(!outfile) cout << "error" << endl;
	for (int i = 0; i<bmpHeight; i++)
	{
	for (int j = 0; j<bmpWidth; j++)
	{
	outfile << out_r[i][j] << " ";
	//cout << out_g[i][j] << endl;
	//cout << out_b[i][j] << endl;
	}
	outfile << "\n";
	}
	outfile.close();
	*/
	// jiang tuxiang shuju cunpan .
	char writePath[] = "D:\\C++_file\\image_deal_C++\\read_BMP\\1.bmp";
	saveBmp(writePath, pBmpBuf, bmpWidth, bmpHeight, biBitCount, pColorTable);
	//清除緩衝區，pBmpBuf和pColorTable是全域性變數，在檔案讀入時申請的空間
	delete[]pBmpBuf;
	if (biBitCount == 8)
		delete[]pColorTable;
}
//
int main()
{
	doIt();
	system("pause");
	return 0;
}