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114 lines
4.4 KiB
C++
114 lines
4.4 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Sample program showing how to add, modify and delete Exif metadata.
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#include <exiv2/exiv2.hpp>
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#include <iostream>
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int main(int argc, char* const argv[]) {
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try {
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Exiv2::XmpParser::initialize();
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::atexit(Exiv2::XmpParser::terminate);
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#ifdef EXV_ENABLE_BMFF
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Exiv2::enableBMFF();
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#endif
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if (argc != 2) {
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std::cout << "Usage: " << argv[0] << " file\n";
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return 1;
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}
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std::string file(argv[1]);
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// Container for exif metadata. This is an example of creating
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// exif metadata from scratch. If you want to add, modify, delete
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// metadata that exists in an image, start with ImageFactory::open
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Exiv2::ExifData exifData;
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// *************************************************************************
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// Add to the Exif data
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// This is the quickest way to add (simple) Exif data. If a metadatum for
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// a given key already exists, its value is overwritten. Otherwise a new
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// tag is added.
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exifData["Exif.Image.Model"] = "Test 1"; // AsciiValue
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exifData["Exif.Image.SamplesPerPixel"] = uint16_t(162); // UShortValue
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exifData["Exif.Image.XResolution"] = -2; // LongValue
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exifData["Exif.Image.YResolution"] = Exiv2::Rational(-2, 3); // RationalValue
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std::cout << "Added a few tags the quick way.\n";
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// Create a ASCII string value (note the use of create)
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auto v = Exiv2::Value::create(Exiv2::asciiString);
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// Set the value to a string
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v->read("1999:12:31 23:59:59");
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// Add the value together with its key to the Exif data container
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Exiv2::ExifKey key("Exif.Photo.DateTimeOriginal");
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exifData.add(key, v.get());
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std::cout << "Added key \"" << key << "\", value \"" << *v << "\"\n";
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// Now create a more interesting value (without using the create method)
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Exiv2::URationalValue rv;
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// Set two rational components from a string
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rv.read("1/2 1/3");
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// Add more elements through the extended interface of rational value
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rv.value_.emplace_back(2, 3);
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rv.value_.emplace_back(3, 4);
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// Add the key and value pair to the Exif data
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key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
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exifData.add(key, &rv);
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std::cout << "Added key \"" << key << "\", value \"" << rv << "\"\n";
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// *************************************************************************
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// Modify Exif data
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// Since we know that the metadatum exists (or we don't mind creating a new
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// tag if it doesn't), we can simply do this:
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Exiv2::Exifdatum& tag = exifData["Exif.Photo.DateTimeOriginal"];
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std::string date = tag.toString();
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date.replace(0, 4, "2000");
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tag.setValue(date);
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std::cout << "Modified key \"" << tag.key() << "\", new value \"" << tag.value() << "\"\n";
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// Alternatively, we can use findKey()
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key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
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auto pos = exifData.findKey(key);
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if (pos == exifData.end())
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throw Exiv2::Error(Exiv2::ErrorCode::kerErrorMessage, "Key not found");
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// Get a pointer to a copy of the value
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v = pos->getValue();
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// Downcast the Value pointer to its actual type
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auto prv = dynamic_cast<Exiv2::URationalValue*>(v.get());
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if (!prv)
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throw Exiv2::Error(Exiv2::ErrorCode::kerErrorMessage, "Downcast failed");
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rv = Exiv2::URationalValue(*prv);
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// Modify the value directly through the interface of URationalValue
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rv.value_.at(2) = {88, 77};
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// Copy the modified value back to the metadatum
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pos->setValue(&rv);
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std::cout << "Modified key \"" << key << "\", new value \"" << pos->value() << "\"\n";
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// *************************************************************************
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// Delete metadata from the Exif data container
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// Delete the metadatum at iterator position pos
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key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
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pos = exifData.findKey(key);
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if (pos == exifData.end())
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throw Exiv2::Error(Exiv2::ErrorCode::kerErrorMessage, "Key not found");
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exifData.erase(pos);
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std::cout << "Deleted key \"" << key << "\"\n";
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// *************************************************************************
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// Finally, write the remaining Exif data to the image file
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auto image = Exiv2::ImageFactory::open(file);
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image->setExifData(exifData);
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image->writeMetadata();
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return 0;
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} catch (Exiv2::Error& e) {
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std::cout << "Caught Exiv2 exception '" << e << "'\n";
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return -1;
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}
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}
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