c++获取图像的长宽 opencv_C++实现读取图片长度和宽度

#include

#include

#include

using namespace std;

class CImage

{

private:

long m_Width;

long m_Height;

int get_extension(string fname);

public:

CImage()

{

m_Width = 0;

m_Height = 0;

};

void LoadImage(char* fname);

long get_width()

{

return m_Width;

};

long get_height()

{

return m_Height;

};

};

int CImage::get_extension(string fname)

{

char c = fname.at(fname.length()-1);

char c2 = fname.at(fname.length()-3);

if ((c == 'f') && (c2 == 'g')){ // file extension name is gif

return 1;

}else if ((c == 'g') && (c2 == 'j')){ // file extension name is jpg

return 2;

}else if ((c == 'g') && (c2 == 'p')){ // file extension name is png

return 3;

}else if ((c == 'p') && (c2 == 'b')){ // file extension name is bmp

return 4;

}

return 0;

}

void CImage::LoadImage(char *fname)

{

m_Width = m_Height = 0;

ifstream ffin(fname, std::ios::binary);

if (!ffin){

cout<

return;

}

int result = get_extension(fname);

char s1[2] = {0}, s2[2] = {0};

switch(result)

{

case 1: // gif

ffin.seekg(6);

ffin.read(s1, 2);

ffin.read(s2, 2);

m_Width = (unsigned int)(s1[1])<<8|(unsigned int)(s1[0]);

m_Height = (unsigned int)(s2[1])<<8|(unsigned int)(s2[0]);

break;

case 2: // jpg

ffin.seekg(164);

ffin.read(s1, 2);

ffin.read(s2, 2);

m_Width = (unsigned int)(s1[1])<<8|(unsigned int)(s1[0]);

m_Height = (unsigned int)(s2[1])<<8|(unsigned int)(s2[0]);

break;

case 3: // png

ffin.seekg(17);

ffin.read(s1, 2);

ffin.seekg(2, std::ios::cur);

ffin.read(s2, 2);

m_Width = (unsigned int)(s1[1])<<8|(unsigned int)(s1[0]);

m_Height = (unsigned int)(s2[1])<<8|(unsigned int)(s2[0]);

break;

case 4: // bmp

ffin.seekg(18);

ffin.read(s1, 2);

ffin.seekg(2, std::ios::cur);

ffin.read(s2, 2);

m_Width = (unsigned int)(s1[1])<<8|(unsigned int)(s1[0]);

m_Height = (unsigned int)(s2[1])<<8|(unsigned int)(s2[0]);

break;

default:

cout<

break;

}

ffin.close();

};

int main(int argc, char *argv[])

{

if (argc < 2){

printf("usage: program imagefilename/n");

return 0;

}

CImage test;

test.LoadImage(argv[1]);

cout<

cout<

return 0;

}