c++读取BMP文件(24位)

 #include "StdAfx.h"
#include "stdio.h"
#include "memory.h"
#include "stdlib.h"

#define PIXPLINE  320

typedef struct tagRGBQUAD{     //定义每个像素的数据类型
        unsigned char  rgbBlue;
        unsigned char  rgbGreen;
        unsigned char  rgbRed;
}    RGBQUAD;

int bmp_read(unsigned char *image, int xsize, int ysize, char *filename){
    char fname_bmp[128];
    sprintf(fname_bmp, "%s.bmp", filename);
   
    FILE *fp;
    if (!(fp = fopen(fname_bmp, "rb")))
      return -1;
     
    unsigned char header[54];
    fread(header, sizeof(unsigned char), 54, fp);
    fread(image, sizeof(unsigned char), (size_t)(long)xsize * ysize * 3, fp);
   
    fclose(fp);
    return 0;
}

int bmp_write(unsigned char *image, int xsize, int ysize, char *filename) {
    unsigned char header[54] ={
      0x42, 0x4d, 0, 0, 0, 0, 0, 0, 0, 0,
        54, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 24, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0
    };
   
    long file_size = (long)xsize * (long)ysize * 3 + 54;
    header[2] = (unsigned char)(file_size &0x000000ff);
    header[3] = (file_size >> 8) & 0x000000ff;
    header[4] = (file_size >> 16) & 0x000000ff;
    header[5] = (file_size >> 24) & 0x000000ff;
   
    long width = xsize;
    header[18] = width & 0x000000ff;
    header[19] = (width >> 8) &0x000000ff;
    header[20] = (width >> 16) &0x000000ff;
    header[21] = (width >> 24) &0x000000ff;
   
    long height = ysize;
    header[22] = height &0x000000ff;
    header[23] = (height >> 8) &0x000000ff;
    header[24] = (height >> 16) &0x000000ff;
    header[25] = (height >> 24) &0x000000ff;

    char fname_bmp[128];
    sprintf(fname_bmp, "%s.bmp", filename);
   
    FILE *fp;
    if (!(fp = fopen(fname_bmp, "wb")))
      return -1;
     
    fwrite(header, sizeof(unsigned char), 54, fp);
    fwrite(image, sizeof(unsigned char), (size_t)(long)xsize * ysize * 3, fp);
   
    fclose(fp);
    return 0;
}

void clonebmp(unsigned char *image,int xsize,int ysize)
{
    bmp_read(image, xsize, ysize, ".//1");  
    bmp_write(image, xsize, ysize, ".//2");
}

    /**//****************************************************************************
* 名称：youwritetobmp()
* 功能：写入bmp文件
* 入口参数：RGBQUAD *pixarr ---- 要写入的像素数组指针, int xsize ---- 图像宽度, int ysize ---- 图像高度, char *filename --图像名称
* 出口参数：无
* 返回值：-1:错误  ；0：正确
****************************************************************************/
int youwritetobmp(RGBQUAD *pixarr, int xsize, int ysize, char *filename){
    unsigned char header[54] ={
      0x42, 0x4d, 0, 0, 0, 0, 0, 0, 0, 0,
        54, 0, 0, 0, 40, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 1, 0, 24, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0
    };
    int i;
    int j;
    long file_size = (long)xsize * (long)ysize * 3 + 54;
    header[2] = (unsigned char)(file_size &0x000000ff);
    header[3] = (file_size >> 8) & 0x000000ff;
    header[4] = (file_size >> 16) & 0x000000ff;
    header[5] = (file_size >> 24) & 0x000000ff;
   
    long width;
    if(!(xsize%4))    width=xsize;
    else            width= xsize+(4-xsize%4);    //如不是4的倍数，则转换成4的倍数
    header[18] = width & 0x000000ff;
    header[19] = (width >> 8) &0x000000ff;
    header[20] = (width >> 16) &0x000000ff;
    header[21] = (width >> 24) &0x000000ff;
   
    long height = ysize;
    header[22] = height &0x000000ff;
    header[23] = (height >> 8) &0x000000ff;
    header[24] = (height >> 16) &0x000000ff;
    header[25] = (height >> 24) &0x000000ff;

    char fname_bmp[128];
    sprintf(fname_bmp, "%s.bmp", filename);
   
    FILE *fp;
    if (!(fp = fopen(fname_bmp, "wb")))
      return -1;
     
    fwrite(header, sizeof(unsigned char), 54, fp);

    RGBQUAD zero = {0,0,0};  //不足字节，用zero填充
   
    for(j=0;j<ysize;j++){
        if(!(xsize%4)){
            for(i=0;i<xsize;i++){
                 fwrite(pixarr+i, sizeof(RGBQUAD),1, fp);
            }
        }
        else
        {
            for(i=0;i<xsize;i++){
                 fwrite(pixarr+i, sizeof(RGBQUAD),1, fp);
            }
            for(i=xsize;i<xsize+(4-xsize%4);i++){
                fwrite(&zero, sizeof(RGBQUAD),1, fp);
            }
        }
    }
   
    fclose(fp);
    return 0;

}

int main()
{
    unsigned char *image;
    int xsize = 320;
    int ysize = 163;

    RGBQUAD pixarray[PIXPLINE]; //一行像素值数组

    image = (unsigned char *)malloc((size_t)xsize * ysize * 3);
   
 if (image == NULL)
      return -1;
    clonebmp(image,xsize,ysize);    //功能一：实现一副图像的拷贝

    //youwritetobmp(pixarray,xsize,ysize,"yourimage");//功能二：实现像素的精确绘制,像素值在pixarray数组中
   
    free(image);
     return 0;
}