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;
}