如何使用C将图像的BMP文件转换为数组 [英] How to convert a BMP file of an image into array using C

问题描述

我想编写一个程序，使用C中的宏将图像的位图文件转换为二进制形式



我尝试过：

I want to write a program to convert a bitmap file of an image into binary form using macros in C

What I have tried:

#include<stdio.h> 
#include<conio.h>
#include<stdlib.h> 
#include<math.h>
#define RGB(r,g,b) (r|g<<8|b<<16)

long extract(FILE *,long ,int );  
void information(FILE *);     

long extract(FILE *fp1,long offset,int size) 
{
     unsigned char *ptr;
     unsigned char temp='0';
     long value=0L;     
	 int i;       //to initialize the ptr     
	 ptr=&temp;       //sets the file pointer at specific position i.e. after the offset     
	 fseek(fp1,offset,SEEK_SET);       //now extracting (size) values starting from the offset    
	  
	 for(i=1;i<=size;i++)     
	 {         
	 	 fread(ptr,sizeof(char),1,fp1);         
		 value=(long)(value+(*ptr)*(pow(256,(i-1))));   //combining the values one after another in a single variable    
	 }
	 return value; 
}

void information(FILE *fp1) 
{ 
	 printf("\nThe width of the bitmap in pixel : %d pixel\n",(int)extract(fp1,18L,4));     
	 printf("\nThe height of the bitmap in pixel : %d pixel\n",(int)extract(fp1,22L,4));     
}       

int main() 
{ 
      int row,col;     
	  int i,j,k;     
	  int dataoffset,offset;     
	  char num[2];     
	  int color;
	  FILE *fp1,*fp2;         
	  if((fp1=fopen("C:\\Users\\Raghava\\Desktop\\logo104.bmp","rb"))==NULL)     
	  {
	           printf("\a\nCant open the image.\nSystem is exiting.");         
			      
	  }       //setting the file pointer at the beginning 
     
	  rewind(fp1);       //CHECKING WHETHER THE FILE IS IN BMP FORMAT OR NOT, WE CHECK THE NUMBER OF THE FILE, NUMBER'S OFFSET IS 0 i.e. IT'S STORED AT THE FRONT OF THE IMAGE, AND THE SIZE IS 2       //at first extracting the number     
	  for(i=0;i<2;i++)     
	  {  
	         num[i]=(char)extract(fp1,i,1); 
      }       //now checking     
	  if((num[0]=='B') && (num[1]=='M'));     
	  else    
	  {         
	  		printf("\a The image is not a bitmap image.\n System is exiting ...... ");             
	  }         //storing the header information 
	      
	  information(fp1);       //get the starting position or offset of the data(pixel)     
	  dataoffset=(int)extract(fp1,10,4);
	  
	  row=(int)extract(fp1,22,4);         //printf("%d\n",row);       //get the number of columns     
	  col=(int)extract(fp1,18,4);         //printf("%d\n",col);         //storing the data     
	  
	  if((fp2=fopen("pixel2.txt","wb"))==NULL)     
	  { 
	          printf("\a\n Error while creating a file.\n System is exiting....");         
			  //exit(0);     
	  }        
	     
	  offset=dataoffset; 
	  for(k=0;k<row;k++)       
	  {
	  	for(j=0;j<col;j++) 
	  	{	       
	  		/*if(RGB(0,0,0))
	  		{
	  			fprintf(fp2,"1");
			}
			else
			{
				fprintf(fp2,"0");
			}*/
	    }
	    fprintf(fp2,"\r\n");
	  }

	  printf("\n For pixels see pixel2.txt.");          
	  return 0; 
}

推荐答案

您需要读取每像素的位数：

You'll need to read the number of bits per pixel:

bpp=(int)extract(fp1,24,2); 

如何读取每个像素取决于每个像素的位数。对于最常见的24 bpp的情况，你可以读取3个字节，它将是你的像素的蓝色，绿色和红色值。



看看这里的完整说明： BMP文件格式 - 维基百科 [ ^ ]

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