addmoddel.cpp

Sample usage of high-level metadata operations.

00001 // ***************************************************************** -*- C++ -*-
00002 // addmoddel.cpp, $Rev: 1271 $
00003 // Sample program showing how to add, modify and delete Exif metadata.
00004 
00005 #include <exiv2/image.hpp>
00006 #include <exiv2/exif.hpp>
00007 #include <iostream>
00008 #include <iomanip>
00009 #include <cassert>
00010 
00011 int main(int argc, char* const argv[])
00012 try {
00013     if (argc != 2) {
00014         std::cout << "Usage: " << argv[0] << " file\n";
00015         return 1;
00016     }
00017     std::string file(argv[1]);
00018 
00019     // Container for exif metadata. This is an example of creating
00020     // exif metadata from scratch. If you want to add, modify, delete
00021     // metadata that exists in an image, start with ImageFactory::open
00022     Exiv2::ExifData exifData;
00023 
00024     // *************************************************************************
00025     // Add to the Exif data
00026 
00027     // This is the quickest way to add (simple) Exif data. If a metadatum for
00028     // a given key already exists, its value is overwritten. Otherwise a new
00029     // tag is added.
00030     exifData["Exif.Image.Model"] = "Test 1";                     // AsciiValue
00031     exifData["Exif.Image.SamplesPerPixel"] = uint16_t(162);      // UShortValue
00032     exifData["Exif.Image.XResolution"] = int32_t(-2);            // LongValue
00033     exifData["Exif.Image.YResolution"] = Exiv2::Rational(-2, 3); // RationalValue
00034     std::cout << "Added a few tags the quick way.\n";
00035 
00036     // Create a ASCII string value (note the use of create)
00037     Exiv2::Value::AutoPtr v = Exiv2::Value::create(Exiv2::asciiString);
00038     // Set the value to a string
00039     v->read("1999:12:31 23:59:59");
00040     // Add the value together with its key to the Exif data container
00041     Exiv2::ExifKey key("Exif.Photo.DateTimeOriginal");
00042     exifData.add(key, v.get());
00043     std::cout << "Added key \"" << key << "\", value \"" << *v << "\"\n";
00044 
00045     // Now create a more interesting value (without using the create method)
00046     Exiv2::URationalValue::AutoPtr rv(new Exiv2::URationalValue);
00047     // Set two rational components from a string
00048     rv->read("1/2 1/3");
00049     // Add more elements through the extended interface of rational value
00050     rv->value_.push_back(std::make_pair(2,3));
00051     rv->value_.push_back(std::make_pair(3,4));
00052     // Add the key and value pair to the Exif data
00053     key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
00054     exifData.add(key, rv.get());
00055     std::cout << "Added key \"" << key << "\", value \"" << *rv << "\"\n";
00056 
00057     // *************************************************************************
00058     // Modify Exif data
00059 
00060     // Since we know that the metadatum exists (or we don't mind creating a new
00061     // tag if it doesn't), we can simply do this:
00062     Exiv2::Exifdatum& tag = exifData["Exif.Photo.DateTimeOriginal"];
00063     std::string date = tag.toString();
00064     date.replace(0, 4, "2000");
00065     tag.setValue(date);
00066     std::cout << "Modified key \"" << key
00067               << "\", new value \"" << tag.value() << "\"\n";
00068 
00069     // Alternatively, we can use findKey()
00070     key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
00071     Exiv2::ExifData::iterator pos = exifData.findKey(key);
00072     if (pos == exifData.end()) throw Exiv2::Error(1, "Key not found");
00073     // Get a pointer to a copy of the value
00074     v = pos->getValue();
00075     // Downcast the Value pointer to its actual type
00076     Exiv2::URationalValue* prv = dynamic_cast<Exiv2::URationalValue*>(v.release());
00077     if (prv == 0) throw Exiv2::Error(1, "Downcast failed");
00078     rv = Exiv2::URationalValue::AutoPtr(prv);
00079     // Modify the value directly through the interface of URationalValue
00080     rv->value_[2] = std::make_pair(88,77);
00081     // Copy the modified value back to the metadatum
00082     pos->setValue(rv.get());
00083     std::cout << "Modified key \"" << key
00084               << "\", new value \"" << pos->value() << "\"\n";
00085 
00086     // *************************************************************************
00087     // Delete metadata from the Exif data container
00088 
00089     // Delete the metadatum at iterator position pos
00090     key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
00091     pos = exifData.findKey(key);
00092     if (pos == exifData.end()) throw Exiv2::Error(1, "Key not found");
00093     exifData.erase(pos);
00094     std::cout << "Deleted key \"" << key << "\"\n";
00095 
00096     // *************************************************************************
00097     // Finally, write the remaining Exif data to the image file
00098     Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(file);
00099     assert(image.get() != 0);
00100 
00101     image->setExifData(exifData);
00102     image->writeMetadata();
00103 
00104     return 0;
00105 }
00106 catch (Exiv2::AnyError& e) {
00107     std::cout << "Caught Exiv2 exception '" << e << "'\n";
00108     return -1;
00109 }

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