Question

如何用c语言读取图片

Answer 1

#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);

}

扩展资料

C语言实现一个图片的读出和写入

#include <stdlib.h>

#include <windows.h>

int file_size(char* filename)//获取文件名为filename的文件大小。

{

FILE *fp = fopen(filename, "rb");//打开文件。

int size;

if(fp == NULL) // 打开文件失败

return -1;

fseek(fp, 0, SEEK_END);//定位文件指针到文件尾。

size=ftell(fp);//获取文件指针偏移量，即文件大小。

fclose(fp);//关闭文件。

return size;

}

int main ()

{

int size=0;

size=file_size("qw");

printf("%d\n",size);

FILE * pFile,*qw;

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

qw   =fopen("qw","r");

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

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

printf("%d\n",size);

fread(buffer,1,size,qw);

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

fclose (pFile);

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

return 0;

}

Answer 2

　　c语言读取图片原理：通过文件流的方式读入到Byte的二进制数组中，之后，使用图像分析算法将图像显示到屏幕上，要将数组中的值转换为像素。

　　参考代码如下：

//function definition
void ImageRead(AnsiString name,int &width,int &height,int *r,int *g,int *b)
{
    //read image
    FILE *fp; 
    if((fp=fopen(name.c_str(),"rb"))==NULL) {
        printf("cannot open bmp.name\n");
        return ;
    }    
    fread(&bfType,sizeof(WORD),1,fp); 
    if(bfType!=0x4d42) {//该值必需是0x4D42，也就是字符'BM'
        printf("the input map is not bmp type");        
        return ;
    } 
    fread(&bfSize,sizeof(DWORD),1,fp);
    fread(&bfReserved1,sizeof(WORD),1,fp); 
    fread(&bfReserved2,sizeof(WORD),1,fp); 
    fread(&bfOffBits,sizeof(DWORD),1,fp); 
    fread(&bih,sizeof(BITMAPINFOHEADER),1,fp); 
    width=bih.biWidth ; 
    height=bih.biHeight;
    if(width % 4 !=0) 
        width=width+ (4-width % 4); 
    DWORD size=width*(bih.biBitCount/8)*height;
    unsigned char* pData=new unsigned char[size]; 

    fread(pData,size,1,fp); 
    
    int bmWidthBytes=width*bih.biBitCount /8; 
    int bmBitsPixel=bih.biBitCount ; 
    int nBit=bmBitsPixel/8; 

    int z; 
    
    for (int y=0; y<height; y++) 
    { 
        for (int x=0; x<width; x++) 
        { 
            z=height-y-1; 
            *(r+(y*width+x))=pData[x*nBit+2+z*bmWidthBytes];
            *(g+(y*width+x))=pData[x*nBit+1+z*bmWidthBytes];
            *(b+(y*width+x))=pData[x*nBit+z*bmWidthBytes];
        } 
    } 
}

void ImageWrite(AnsiString name1,int *r,int *g,int *b)
{
    //read image
    FILE *fw;
    fw=fopen(name1.c_str(),"wb");
    
    fwrite(&bfType,sizeof(WORD),1,fw);
    fwrite(&bfSize,sizeof(DWORD),1,fw);
    fwrite(&bfReserved1,sizeof(WORD),1,fw); 
    fwrite(&bfReserved2,sizeof(WORD),1,fw); 
    fwrite(&bfOffBits,sizeof(DWORD),1,fw); 
    fwrite(&bih,sizeof(BITMAPINFOHEADER),1,fw);

    int width=bih.biWidth ; 
    int height=bih.biHeight;
    if(width % 4 !=0) 
        width=width+ (4-width % 4); 
    DWORD size=width*(bih.biBitCount/8)*height;
    unsigned char* pData=new unsigned char[size]; 

    int bmWidthBytes=width*bih.biBitCount /8; 
    int bmBitsPixel=bih.biBitCount ; 
    int nBit=bmBitsPixel/8; 

    
    int z; 
    for (int y=0; y<height; y++) 
    { 
        for (int x=0; x<width; x++) 
        { 
            z=height-y-1; 
            pData[x*nBit+2+z*bmWidthBytes]=*(r+(y*width+x));
            pData[x*nBit+1+z*bmWidthBytes]=*(g+(y*width+x));
            pData[x*nBit+z*bmWidthBytes]=*(b+(y*width+x));        
        } 
    } 

    fwrite(pData,size,1,fw);
}

Answer 3

图片也是文件，就用fopen(),fread()等操作文件的函数就可以读了，但是只有你知道图片文件的确切格式，才可能正确读取