55aebc0686
Image::read/writeMetadata and ImageFactory::open now throw Error in case of failure. Applications therefore now need an exception handler for the error handling of such function calls. This should result in shorter and simpler application code.
110 lines
4.5 KiB
C++
110 lines
4.5 KiB
C++
// ***************************************************************** -*- C++ -*-
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// addmoddel.cpp, $Rev$
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// Sample program showing how to add, modify and delete Exif metadata.
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#include "image.hpp"
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#include "exif.hpp"
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#include <iostream>
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#include <iomanip>
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#include <cassert>
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int main(int argc, char* const argv[])
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try {
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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"] = int32_t(-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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Exiv2::Value::AutoPtr 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::AutoPtr rv(new Exiv2::URationalValue);
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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_.push_back(std::make_pair(2,3));
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rv->value_.push_back(std::make_pair(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.get());
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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 \"" << key
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<< "\", 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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Exiv2::ExifData::iterator pos = exifData.findKey(key);
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if (pos == exifData.end()) throw Exiv2::Error(1, "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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Exiv2::URationalValue* prv = dynamic_cast<Exiv2::URationalValue*>(v.release());
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if (prv == 0) throw Exiv2::Error(1, "Downcast failed");
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rv = Exiv2::URationalValue::AutoPtr(prv);
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// Modify the value directly through the interface of URationalValue
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rv->value_[2] = std::make_pair(88,77);
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// Copy the modified value back to the metadatum
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pos->setValue(rv.get());
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std::cout << "Modified key \"" << key
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<< "\", 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()) throw Exiv2::Error(1, "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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Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(file);
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assert(image.get() != 0);
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image->setExifData(exifData);
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image->writeMetadata();
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return 0;
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}
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catch (Exiv2::AnyError& 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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