blame: src/exifreader.cpp

#include "exifreader.h"

#include <QFile>

#include <QImageReader>

#include <exiv2/exiv2.hpp>

#include <sys/stat.h>

#include <fcntl.h>

#include <filesystem>

#include <unistd.h>

// Raw EXIF date format is "YYYY:MM:DD HH:MM:SS"; reformat date separators to dashes

static QString formatDate(const QString &raw)

{

    if (raw.size() >= 10 && raw[4] == u':' && raw[7] == u':')

        return raw.left(4) + u'-' + raw.mid(5, 2) + u'-' + raw.mid(8, 2) + raw.mid(10);

    return raw;

}

static QString findTag(const Exiv2::ExifData &exif, const std::string &key)

{

    try {

        Exiv2::ExifData::const_iterator it = exif.findKey(Exiv2::ExifKey(key));

        if (it != exif.end())

            return QString::fromStdString(it->print(&exif)).trimmed();

    } catch (...) {}

    return {};

}

static void addField(QList<QPair<QString, QString>> &result, const char *label, const QString &value)

{

    if (!value.isEmpty())

        result.append({QString::fromLatin1(label), value});

}

// EXIF orientation values run 1-8 and may encode mirroring. A 90-degree

// rotation maps each value to another; the tables below cover all eight so

// mirrored images stay correct. Unknown values are treated as 1 (normal).

static int orientationRotatedClockwise(int orientation)

{

    switch (orientation) {

    case 1: return 6;

    case 2: return 7;

    case 3: return 8;

    case 4: return 5;

    case 5: return 2;

    case 6: return 3;

    case 7: return 4;

    case 8: return 1;

    default: return 6;

    }

}

static int orientationRotatedCounterClockwise(int orientation)

{

    switch (orientation) {

    case 1: return 8;

    case 2: return 5;

    case 3: return 6;

    case 4: return 7;

    case 5: return 4;

    case 6: return 1;

    case 7: return 2;

    case 8: return 3;

    default: return 8;

    }

}

bool ExifData::isEmpty() const

{

    return captionAbstract.isEmpty() && description.isEmpty()

        && dateTime.isEmpty() && make.isEmpty() && model.isEmpty()

        && exposureTime.isEmpty() && fNumber.isEmpty() && iso.isEmpty()

        && focalLength.isEmpty() && flash.isEmpty()

        && filename.isEmpty() && dimensions.isEmpty() && fileSize.isEmpty();

}

QList<QPair<QString, QString>> ExifData::toList() const

{

    QList<QPair<QString, QString>> result;

    addField(result, "Caption",      captionAbstract);

    addField(result, "Description",  description);

    addField(result, "Date/Time",    dateTime);

    addField(result, "Camera Make",  make);

    addField(result, "Camera Model", model);

    addField(result, "Exposure",     exposureTime);

    addField(result, "Aperture",     fNumber);

    addField(result, "ISO",          iso);

    addField(result, "Focal Length", focalLength);

    addField(result, "Flash",        flash);

    addField(result, "Filename",     filename);

    addField(result, "Dimensions",   dimensions);

    addField(result, "File Size",    fileSize);

    return result;

}

ExifData ExifReader::read(const QByteArray &path)

{

    ExifData data;

    struct ::stat st{};

    if (::stat(path.constData(), &st) != 0 || !S_ISREG(st.st_mode))

        return data;

    // Filename

    {

        const std::filesystem::path fsPath(path.toStdString());

        const std::string nativeName = fsPath.filename().native();

        data.filename = QString::fromLocal8Bit(

            nativeName.data(), static_cast<qsizetype>(nativeName.size()));

    }

    // File size

    {

        qint64 size = static_cast<qint64>(st.st_size);

        if (size < 1024)

            data.fileSize = QString::number(size) + QLatin1String(" B");

        else if (size < 1024 * 1024)

            data.fileSize = QString::number(size / 1024.0, 'f', 1) + QLatin1String(" KiB");

        else

            data.fileSize = QString::number(size / (1024.0 * 1024.0), 'f', 1) + QLatin1String(" MiB");

    }

    // Image dimensions via Qt (reads only the header, no full decode needed)

    {

        int fd = ::open(path.constData(), O_RDONLY | O_CLOEXEC);

        if (fd >= 0) {

            QFile file;

            if (file.open(fd, QIODevice::ReadOnly, QFileDevice::AutoCloseHandle)) {

                QImageReader reader(&file);

                reader.setDecideFormatFromContent(true);

                QSize sz = reader.size();

                        if (sz.isValid())

                    data.dimensions = QString::fromLatin1("%1 * %2")

                                          .arg(sz.width()).arg(sz.height());

            } else {

                ::close(fd);

            }

        }

    }

    // EXIF tags via exiv2

    try {

        std::unique_ptr<Exiv2::Image> image =

            Exiv2::ImageFactory::open(path.toStdString());

        image->readMetadata();

        const Exiv2::ExifData &exif = image->exifData();

        data.dateTime = formatDate(findTag(exif, "Exif.Photo.DateTimeOriginal"));

        if (data.dateTime.isEmpty())

            data.dateTime = formatDate(findTag(exif, "Exif.Image.DateTime"));

        data.make         = findTag(exif, "Exif.Image.Make");

        data.model        = findTag(exif, "Exif.Image.Model");

        data.exposureTime = findTag(exif, "Exif.Photo.ExposureTime");

        data.fNumber      = findTag(exif, "Exif.Photo.FNumber");

        data.iso          = findTag(exif, "Exif.Photo.ISOSpeedRatings");

        data.focalLength  = findTag(exif, "Exif.Photo.FocalLength");

        data.flash        = findTag(exif, "Exif.Photo.Flash");

        data.description  = findTag(exif, "Exif.Image.ImageDescription");

        // IPTC Caption-Abstract

        const Exiv2::IptcData &iptc = image->iptcData();

        auto iptcIt = iptc.findKey(Exiv2::IptcKey("Iptc.Application2.Caption"));

        if (iptcIt != iptc.end())

            data.captionAbstract = QString::fromStdString(iptcIt->toString()).trimmed();

    } catch (const Exiv2::Error &) {

        // No EXIF or unsupported format — leave tags empty

    }

    return data;

}

bool ExifReader::saveCaption(const QByteArray &path,

                             const QString    &caption,

                             const ExifData   &oldData)

{

    try {

        std::unique_ptr<Exiv2::Image> image =

            Exiv2::ImageFactory::open(path.toStdString());

        image->readMetadata();

        // Erase all existing Caption-Abstract entries then add the new one

        Exiv2::IptcData &iptc = image->iptcData();

        {

            Exiv2::IptcKey key("Iptc.Application2.Caption");

            auto it = iptc.findKey(key);

            while (it != iptc.end()) {

                it = iptc.erase(it);

                it = iptc.findKey(key);

            }

        }

        Exiv2::Iptcdatum datum(Exiv2::IptcKey("Iptc.Application2.Caption"));

        datum.setValue(caption.toStdString());

        iptc.add(datum);

        // If Caption-Abstract and Description were previously in sync, keep them in sync

        if (oldData.captionAbstract == oldData.description) {

            image->exifData()["Exif.Image.ImageDescription"] = caption.toStdString();

        }

        image->writeMetadata();

        return true;

    } catch (const Exiv2::Error &) {

        return false;

    }

}

bool ExifReader::rotate(const QByteArray &path, bool clockwise)

{

    try {

        std::unique_ptr<Exiv2::Image> image =

            Exiv2::ImageFactory::open(path.toStdString());

        image->readMetadata();

        Exiv2::ExifData &exif = image->exifData();

        int current = 1; // EXIF default when the tag is absent

        auto it = exif.findKey(Exiv2::ExifKey("Exif.Image.Orientation"));

        if (it != exif.end())

            current = static_cast<int>(it->toInt64());

        const int updated = clockwise ? orientationRotatedClockwise(current)

                                      : orientationRotatedCounterClockwise(current);

        exif["Exif.Image.Orientation"] = static_cast<uint16_t>(updated);

        image->writeMetadata();

        return true;

    } catch (const Exiv2::Error &) {

        return false;

    }

}