Exiv2
Loading...
Searching...
No Matches
mrwthumb.cpp

Sample program to extract a Minolta thumbnail from the makernote

// SPDX-License-Identifier: GPL-2.0-or-later
// Sample program to extract a Minolta thumbnail from the makernote
#include <exiv2/exiv2.hpp>
#include <iostream>
int main(int argc, char* const argv[]) {
#ifdef EXV_ENABLE_BMFF
Exiv2::enableBMFF();
#endif
try {
if (argc != 2) {
std::cout << "Usage: " << argv[0] << " file\n";
return EXIT_FAILURE;
}
auto image = Exiv2::ImageFactory::open(argv[1]);
image->readMetadata();
Exiv2::ExifData& exifData = image->exifData();
if (exifData.empty()) {
std::string error(argv[1]);
error += ": No Exif data found in the file";
throw Exiv2::Error(Exiv2::ErrorCode::kerErrorMessage, error);
}
Exiv2::ExifKey key("Exif.Minolta.ThumbnailOffset");
auto format = exifData.findKey(key);
if (format != exifData.end()) {
Exiv2::DataBuf buf = format->dataArea();
// The first byte of the buffer needs to be patched
buf.write_uint8(0, 0xff);
Exiv2::FileIo file("img_thumb.jpg");
file.open("wb");
file.write(buf.c_data(), buf.size());
file.close();
}
return EXIT_SUCCESS;
} catch (Exiv2::Error& e) {
std::cout << "Caught Exiv2 exception '" << e << "'\n";
return EXIT_FAILURE;
}
}
Simple error class used for exceptions. An output operator is provided to print errors to a stream.
Definition: error.hpp:235
A container for Exif data. This is a top-level class of the Exiv2 library. The container holds Exifda...
Definition: exif.hpp:373
bool empty() const
Return true if there is no Exif metadata.
Definition: exif.hpp:459
iterator findKey(const ExifKey &key)
Find the first Exifdatum with the given key, return an iterator to it.
Definition: exif.cpp:460
iterator end()
End of the metadata.
Definition: exif.hpp:433
Concrete keys for Exif metadata and access to Exif tag reference data.
Definition: tags.hpp:271
Provides binary file IO by implementing the BasicIo interface.
Definition: basicio.hpp:283
int open(const std::string &mode)
Open the file using the specified mode.
Definition: basicio.cpp:508
size_t write(const byte *data, size_t wcount) override
Write data to the file. The file position is advanced by the number of bytes written.
Definition: basicio.cpp:315
int close() override
Flush and unwritten data and close the file . It is safe to call close on an already closed instance.
Definition: basicio.cpp:522
static Image::UniquePtr open(const std::string &path, bool useCurl=true)
Create an Image subclass of the appropriate type by reading the specified file. Image type is derived...
Definition: image.cpp:794
static bool initialize(XmpParser::XmpLockFct xmpLockFct=nullptr, void *pLockData=nullptr)
Initialize the XMP Toolkit.
Definition: xmp.cpp:568
static void terminate()
Terminate the XMP Toolkit and unregister custom namespaces.
Definition: xmp.cpp:623
Utility class containing a character array. All it does is to take care of memory allocation and dele...
Definition: types.hpp:124
const byte * c_data(size_t offset=0) const
Returns a (read-only) data pointer.
Definition: types.cpp:175