수다닷컴

질문 제목 : 이 프로그래밍 주석과 어떤 역할을하는지 설명 좀 부탁드려요.ㅠ질문 요약 :프로그래밍 주석과 설명좀 부탁드려요.ㅠ질문 내용 : 헤더

//bmp file header information
typedef struct _bmp_header
{
char charb;
char charm;
unsigned int filesize;
unsigned int reserved;
unsigned int pixel_offset;
unsigned int header_size;
unsigned int image_width;
unsigned int image_height;
unsigned int number_of_planes_and_number_of_bits_per_pixel;
unsigned int compression_type;
unsigned int image_size_with_padding_in_bytes;
unsigned int horizontal_resolution;
unsigned int veritical_resolution;
unsigned int number_of_colors;
unsigned int number_of_important_colors;
}bmp_header; //end of bmp header
void bmp_file_header_read (file * fp,bmp_header * bmp_header);
void bmp_file_header_write(file * wp,bmp_header * bmp_header);
void change_color_bluetozero(char * image_pixel_ptr,bmp_header * bmp_header,file * fp);

코드
#include stdio.h
#include bmp_header.h
#include malloc.h
//author:hyo jun kim,sejong univ
//date: 10 feb.2012
//this program will read a bmp image file
//and change the blue component of each pixel in that
//file to zero value
//and produce the chagnged bitmap into a new file
//input:a bmp image file
//output:a new bmp file with blue component set to zero
bmp_header bmp_header;
int main()
{

//first read a bitmap file
file * fp = fopen(d:\\blue.bmp,rb);//file open
//first prepare memory for the pixel data
//with image_size_with_padding_in_bytes
bmp_file_header_read (fp,&bmp_header);

char* image_pixel_ptr;
image_pixel_ptr=(char *)malloc(bmp_header.image_size_with_padding_in_bytes);
change_color_bluetozero(image_pixel_ptr,&bmp_header,fp);
//write a new bitmap file
file * wp = fopen(d:\\new_blue.bmp,wb);
bmp_file_header_write(wp,&bmp_header);
fwrite(image_pixel_ptr,bmp_header.image_size_with_padding_in_bytes,1,wp);
fclose(fp);
fclose(wp);
free(image_pixel_ptr);

return 0;
}

void bmp_file_header_read (file * fp,bmp_header * bmp_header)
{

fread(&bmp_header-charb,sizeof(char),1,fp);
fread(&bmp_header-charm,sizeof(char),1,fp);
fread(&bmp_header-filesize,sizeof(unsigned int),1,fp);
fread(&bmp_header-reserved,sizeof(unsigned int),1,fp);
fread(&bmp_header-pixel_offset,sizeof(unsigned int),1,fp);
fread(&bmp_header-header_size,sizeof(unsigned int),1,fp);
fread(&bmp_header-image_width,sizeof(unsigned int),1,fp);
fread(&bmp_header-image_height,sizeof(unsigned int),1,fp);
fread(&bmp_header-number_of_planes_and_number_of_bits_per_pixel,4,1,fp);
fread(&bmp_header-compression_type,sizeof(unsigned int),1,fp);
fread(&bmp_header-image_size_with_padding_in_bytes,sizeof(unsigned int),1,fp);
fread(&bmp_header-horizontal_resolution,sizeof(unsigned int),1,fp);
fread(&bmp_header-veritical_resolution,sizeof(unsigned int),1,fp);
fread(&bmp_header-number_of_colors,sizeof(unsigned int),1,fp);
fread(&bmp_header-number_of_important_colors,sizeof(unsigned int),1,fp);
//bmp header information completely read
//now read the pixel information
}
void bmp_file_header_write(file * wp,bmp_header * bmp_header)
{
fwrite(&bmp_header-charb,sizeof(char),1,wp);
fwrite(&bmp_header-charm,sizeof(char),1,wp);
fwrite(&bmp_header-filesize,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-reserved,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-pixel_offset,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-header_size,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-image_width,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-image_height,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-number_of_planes_and_number_of_bits_per_pixel,4,1,wp);
fwrite(&bmp_header-compression_type,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-image_size_with_padding_in_bytes,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-horizontal_resolution,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-veritical_resolution,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-number_of_colors,sizeof(unsigned int),1,wp);
fwrite(&bmp_header-number_of_important_colors,sizeof(unsigned int),1,wp);
}

void change_color_bluetozero(char * image_pixel_ptr,bmp_header * bmp_header,file * fp)
{
fread(image_pixel_ptr,bmp_header-image_size_with_padding_in_bytes,1,fp); //change the blue part of each pixel to zero
//first calculate the padding size
unsigned int pure_number_of_bytes_per_pixel_one_line=bmp_header-image_width * 3;
unsigned int padding_size=(pure_number_of_bytes_per_pixel_one_line%4);
unsigned int one_line_width_with_padding = bmp_header-image_width*3 +padding_size;

for(int i=0;i30;i++)
{
for(int j=0;jbmp_header-image_width*3;j++)
{
image_pixel_ptr[(one_line_width_with_padding*i) + j]=0;
}
}
}
부탁드려요 ㅠ 이번에도 답변해주시면 정말 감사하겠습니다.

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