C语言实现对bmp格式图片打码

<span style="font-size:14px;">#include<stdio.h> #include<stdlib.h> #include<string.h> #include<unistd.h> #include<errno.h> #include<sys/types.h> #include<sys/stat.h> #include<fcntl.h>   #define WIDTH  1024 #define HEIGHT 768 #define BPP 24 #define BYTES  (BPP / 8) #define HEADER 54   int main(int argc,char* argv[]) {   int xoff,yoff,width,height;   int fd;   int i,j,k;   int offset;   unsigned char pix[BYTES];            if(argc!=6)   {     printf("Usage: %s filename xoff yoff width height/n",argv[0]);     exit(EXIT_FAILURE);   }      xoff=atoi(argv[2]);   yoff=atoi(argv[3]);   width=atoi(argv[4]);   height=atoi(argv[5]);     xoff=HEIGHT -xoff;   yoff=WIDTH - yoff;           fd=open(argv[1],O_WRONLY);   if(fd==-1)   {     perror("open");     exit(EXIT_FAILURE);   }     for(i=xoff;i > xoff - height;i--)   {     for(j=yoff;j > yoff - width;j--)     {       offset = HEADER + (i * WIDTH -j )*BYTES;       lseek(fd, offset, SEEK_SET);       for(k=0; k<BYTES; k++)       {         pix[j] = random();         write(fd ,&pix[j] ,1);       }     }   }   close(fd);   return 0; }</span>