Modify EXIF Data using C++ - c++

Question

We are building a quad copter robot for a competition, and one of the requirements is that we have to capture photos using the camera that is installed on the quad copter.
I wrote a simple OpenCV program that is able to capture them in .jpg format, but my camera or my program are unable to save "latitude" and "longitude" as EXIF on my images.
I've added to my robot a GPS module that can retrieve GPS data while capturing photos and save them to a text file.
So my main problem is adding these data from the text file to the pictures separately while they are captured.
I tried many libraries like:
easyexif
Exiv2
Phil Harvey
Also I tried them in:
Visual C++ .net 2015
Dev C++ (GCC)
Code Blocks (GCC)
and also I worked on PHP but I just can read and extract EIXFs but I can't write new data on my pictures.
How can I solve this problem?

Answer 1

you can use this code. I used Image::GetPropertyIdList method and Reading and Writing Metadata as a material for this code. unfortunately i didnt find any function in opencv that can manipulate Exif.
#include <windows.h>
#include <gdiplus.h>
#include <stdio.h>
#include <Math.h>
#pragma comment(lib,"gdiplus.lib")
using namespace Gdiplus;
int GetEncoderClsid(const WCHAR* format, CLSID* pClsid) //i copy this function from Doc.microsoft.com
{
UINT num = 0; // number of image encoders
UINT size = 0; // size of the image encoder array in bytes
ImageCodecInfo* pImageCodecInfo = NULL;
GetImageEncodersSize(&num, &size);
if (size == 0)
return -1; // Failure
pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
if (pImageCodecInfo == NULL)
return -1; // Failure
GetImageEncoders(num, size, pImageCodecInfo);
for (UINT j = 0; j < num; ++j)
{
if (wcscmp(pImageCodecInfo[j].MimeType, format) == 0)
{
*pClsid = pImageCodecInfo[j].Clsid;
free(pImageCodecInfo);
return j; // Success
}
}
free(pImageCodecInfo);
return -1; }
int main(){
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
Status stat;
CLSID clsid;
Bitmap* bitmap = new Bitmap(L"Source.bmp"); // you can use any Image Format as Source
PropertyItem* propertyItem = new PropertyItem;
// Get the CLSID of the JPEG encoder.
GetEncoderClsid(L"image/jpeg", &clsid);
double dlan = 35.715298; // we supposed that your GPS data is Double if its not skip this step
// convert double to unsigned long array
double coord = dlan;
int sec = (int)round(coord * 3600);
int deg = sec / 3600;
sec = abs(sec % 3600);
int min = sec / 60;
sec %= 60;
unsigned long ulExifCoordFormatLan[6] = { deg, 1, min, 1, sec, 1 };
propertyItem->id = PropertyTagGpsLatitude;
propertyItem->length = sizeof(long) * 2 * 3;
propertyItem->type = PropertyTagTypeRational;
propertyItem->value = ulExifCoordFormatLan;
Status s = bitmap->SetPropertyItem(propertyItem);// saving image to the destination
stat = bitmap->Save(L"Dest.jpg", &clsid, NULL);
if (s == Ok && stat==Ok)
printf("Dest.jpg saved successfully .\n");
delete propertyItem;
delete bitmap;
GdiplusShutdown(gdiplusToken);
return 0;}