c如何讀取圖片

⑴ 用c語言如何讀取和保存jpg圖片文件

#include <stdio.h>

#include <stdlib.h>

#include <windows.h>

int file_size(char* filename)//獲取文件名為filename的文件大小。

{

FILE *fp = fopen(filename, "rb");//打開文件。

int size;

if(fp == NULL) // 打開文件失敗

return -1;

fseek(fp, 0, SEEK_END);//定位文件指針到文件尾。

size=ftell(fp);//獲取文件指針偏移量，即文件大小。

fclose(fp);//關閉文件。

return size;

}

int main ()

{

int size=0;

size=file_size("qw");

printf("%d ",size);

FILE * pFile,*qw;

char *buffer=(char*)malloc(sizeof(char)*size);

qw =fopen("qw","r");

pFile = fopen ( "qwe" , "wb" );

printf("%d== ",pFile);

printf("%d ",size);

fread(buffer,1,size,qw);

fwrite (buffer , sizeof(byte), size , pFile );

fclose (pFile);

rename("qwe","Groot.jpg");

return 0;

}

(1)c如何讀取圖片擴展閱讀：

c語言讀取TXT文件：

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#define MAX_LINE 1024

int main()

{

char buf[MAX_LINE]; /*緩沖區*/

FILE *fp; /*文件指針*/

int len; /*行字元個數*/

if((fp = fopen("test.txt","r")) == NULL)

{

perror("fail to read");

exit (1) ;

}

while(fgets(buf,MAX_LINE,fp) != NULL)

{

len = strlen(buf);

buf[len-1] = ''; /*去掉換行符*/

printf("%s %d ",buf,len - 1);

}

return 0;

}

⑵ 如何用c語言讀取圖片

#include

using namespace std;

#define Twoto1(i,j,w) i*w+j

void createimage(unsigned char *&img, int w, int h)

{img = new unsigned char[w*h];}

void delateimage(unsigned char*img)

{delete []img;}

void readimage(unsigned char*img, int w, int h, char *fname)

{

FILE *fp;

fopen_s(&fp,fname, "rb");

if (fp == NULL){ cout << "error" << endl; return; }

size_t result;

result=fread(img , sizeof(unsigned char), w*h, fp);

if (result != w*h)

{

cout << "Reading error" << endl;

return;

}

else

cout << "Reading Ok!" << endl;

fclose(fp);

}

void mobanjuanji(unsigned char image, unsigned char*image1, int w, int h, float moban[5][5])

{

for (int i = 0; i for (int j = 0; j if (iw - 3 || j>h - 3)

image1[Twoto1(i,j,w)] = 0;

else

{

float temp = 0;

for (int m = 0; m<5; m++)

for (int n = 0; n<5; n++)

{

temp += (image[Twoto1(i-2+m,j-2+n,w)] moban[m][n]);

}

if (temp>255) image1[Twoto1(i, j, w)] = 255;

else if (temp<0) image1[Twoto1(i, j, w)] = 0;

else image1[Twoto1(i, j, w)] = temp;

}

}

void saveimage(unsigned char *img, int w, int h, char *fname)

{

FILE *fp;

fopen_s(&fp, fname, "wb");

if (fp == NULL) { cout << "error" << endl; return; }

size_t result;

result = fwrite(img, sizeof(unsigned char), w*h, fp);

if (result != w*h)

{

cout << "Write error" << endl;

return;

}

else

cout << "Write Ok!" << endl;

fclose(fp);

}

void main()

{

unsigned char *img;

unsigned char *img1;

float moban[5][5] = { {0,0,0,0,0},{0, -1, 0, 1, 0 }, { 0, -2, 0, 2, 0 }, { 0, -1, 0, 1, 0 }, { 0,0,0,0,0 } };

//float moban[5][5] = { 0 };

int w = 512, h = 512;

createimage(img, w, h);

createimage(img1, w, h);

readimage(img, w, h, "E:ss.raw");

mobanjuanji(img, img1,w, h, moban);

saveimage(img, w, h, "E:ss_1.raw");

saveimage(img1, w, h, "E:ss_2.raw");

delateimage(img);

delateimage(img1);

}

(2)c如何讀取圖片擴展閱讀

C語言實現一個圖片的讀出和寫入

#include <stdlib.h>

#include <windows.h>

int file_size(char* filename)//獲取文件名為filename的文件大小。

{

FILE *fp = fopen(filename, "rb");//打開文件。

int size;

if(fp == NULL) // 打開文件失敗

return -1;

fseek(fp, 0, SEEK_END);//定位文件指針到文件尾。

size=ftell(fp);//獲取文件指針偏移量，即文件大小。

fclose(fp);//關閉文件。

return size;

}

int main ()

{

int size=0;

size=file_size("qw");

printf("%d ",size);

FILE * pFile,*qw;

char *buffer=(char*)malloc(sizeof(char)*size);

qw =fopen("qw","r");

pFile = fopen ( "qwe" , "wb" );

printf("%d== ",pFile);

printf("%d ",size);

fread(buffer,1,size,qw);

fwrite (buffer , sizeof(byte), size , pFile );

fclose (pFile);

rename("qwe","Groot.jpg");

return 0;

}