#include <stdio.h>
#include "Windows.h"

BOOL readBmp(char *bmpName);
BOOL saveBmp(char *bmpName, char *imgBuf, int width, int heigh, int biBitCount, RGBQUAD *pColorTable);

char *pBmpBuf; //位图数据
int bmpWidth; // 图像宽度
int bmpHeight; //图像高度
int biBiCount;  //图像类型，每像素位数
RGBQUAD *pColorTable;  //位图颜色表指针

int main()
{
    char readName[] = "read.BMP";
    readBmp(readName);
    char writeName[] = "write.BMP";
    saveBmp(writeName, pBmpBuf, bmpWidth, bmpHeight, biBiCount, pColorTable);
    int lineByte = (bmpWidth*bmpHeight/8+3)/4*4;

    if (biBiCount == 8)
    {
        for (int i = 0; i < bmpWidth/2; i++)
        {
            for (int j = 0; j < bmpHeight/2; j++)
            {
                *(pBmpBuf+i*lineByte+j) = 0;
            }
        }
    }
    else if (biBiCount == 24)
    {/////对于24位真彩图，每个像素占三个字节分别存储R、G、B三个颜色分量的颜色值
        for (int i = 0; i < bmpWidth/2; i++)
        {
            for (int j = 0; j < bmpHeight/2; j++)
            {
                for (int k = 0; k < 3; k++)
                    *(pBmpBuf+i*lineByte+j*3+k) = 0;  //将rgb三个颜色分量设置成黑色
            }
        }
    }
    char Name[] = "copy.BMP";
    saveBmp(Name, pBmpBuf, bmpWidth, bmpHeight, biBiCount, pColorTable);
    delete []pBmpBuf;
    if (biBiCount == 8)
    {
        delete []pColorTable;
    }
   
    return 0;
}

BOOL readBmp(char *bmpName )
{
    FILE *pf = fopen(bmpName, "rb");
    if (pf == NULL) return FALSE;
    printf("read %s succeeded!\n", bmpName);
    fseek(pf, sizeof(BITMAPFILEHEADER), SEEK_SET);
    BITMAPINFOHEADER infoHeader;
    fread(&infoHeader, sizeof(BITMAPINFOHEADER), 1, pf);
    bmpWidth = infoHeader.biWidth;
    bmpHeight = infoHeader.biHeight;
    biBiCount = infoHeader.biBitCount;
    //图像每行的字节数，一定要是4的倍数
    int lineByte = (bmpWidth*bmpHeight/8+3)/4*4;
    pBmpBuf = new char[lineByte*bmpHeight];
    //灰度图像有颜色表
    if (biBiCount == 8)
    {
        pColorTable = new RGBQUAD[256];
        fread(pColorTable, sizeof(RGBQUAD), 1, pf);
    }
    fread(pBmpBuf, lineByte*bmpHeight, 1, pf);
    fclose(pf); //关闭文件
    return TRUE;
}

BOOL saveBmp(char *bmpName, char *imgBuf, int width, int heigh, int biBitCount, RGBQUAD *pColorTable )
{
    FILE *pf = fopen(bmpName, "wb");
    if (pf == NULL) return FALSE;
    printf("write %s succeeded!\n", bmpName);
    //写头文件
    int colorTableSize = 0;
    if (biBitCount == 8)
    {
        colorTableSize = 1024;
    }
    int lineByte = (width*heigh/8+3)/4*4;
   
    BITMAPFILEHEADER filehead;
    filehead.bfOffBits = 54+colorTableSize;
    filehead.bfType = 0x4D42;
    filehead.bfSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+colorTableSize+lineByte*heigh;
    filehead.bfReserved1 = 0;
    filehead.bfReserved2 = 0;
    fwrite(&filehead, sizeof(BITMAPFILEHEADER), 1, pf);
   
    BITMAPINFOHEADER infoHead;
    infoHead.biBitCount = biBitCount;
    infoHead.biWidth = width;
    infoHead.biHeight = heigh;
    infoHead.biSize = 40;
    infoHead.biClrImportant = 0;
    infoHead.biSizeImage = lineByte*heigh;
    infoHead.biClrUsed = 0;
    infoHead.biPlanes = 1;
    infoHead.biXPelsPerMeter = 0;
    infoHead.biYPelsPerMeter = 0;
    fwrite(&infoHead,sizeof(BITMAPINFOHEADER), 1, pf);
   
    if (biBitCount == 8)
    {
        fwrite(pColorTable, sizeof(RGBQUAD), 256, pf);
    }
    fwrite(pBmpBuf, lineByte*heigh, 1, pf);
    fclose(pf);
    return TRUE;
}