OmaPhoto 1.0.0: the Linux port of Compositor

A layered image editor for Linux and Omarchy, ported from Compositor
(github.com/robbietilton/Compositor), whose Swift source is its
specification. It reads and writes Compositor's .comp projects.

Packages for Ubuntu, Fedora and Arch come from the release workflow;
scripts/install/ holds one install script per distribution family,
and flake.nix serves NixOS.

Co-Authored-By: Claude <noreply@anthropic.com>

src/IO/ImageFileDrop.cpp

@@ -0,0 +1,104 @@
+#include "IO/ImageFileDrop.h"
+#include "Document/ProjectWorkspace.h"
+#include "Logging.h"
+#include <QDir>
+#include <QFile>
+#include <QMimeDatabase>
+#include <algorithm>
+
+namespace {
+// Swift's order: PNG, JPEG, HEIC, TIFF, then any picture.
+QStringList pictureFormats(const QMimeData &data)
+{
+    QStringList formats;
+    for (const QString &format : {QStringLiteral("image/png"), QStringLiteral("image/jpeg"), QStringLiteral("image/heic"), QStringLiteral("image/tiff")})
+        if (data.hasFormat(format))
+            formats << format;
+    for (const QString &format : data.formats())
+        if (format.startsWith(QLatin1String("image/")) && !formats.contains(format))
+            formats << format;
+    return formats;
+}
+
+// A dropped picture copied to a file for the importer.
+std::optional<QUrl> temporaryFile(const QMimeData &data)
+{
+    const QStringList formats = pictureFormats(data);
+    if (formats.isEmpty())
+        return std::nullopt;
+    const QString suffix = QMimeDatabase().mimeTypeForName(formats.first()).preferredSuffix();
+    const QString name = QStringLiteral("Dropped-%1.%2").arg(QUuid::createUuid().toString(QUuid::WithoutBraces).toUpper(), suffix.isEmpty() ? QStringLiteral("png") : suffix);
+    QFile file(QDir::temp().filePath(name));
+    const QByteArray bytes = data.data(formats.first());
+    if (!file.open(QIODevice::WriteOnly) || file.write(bytes) != bytes.size() || !file.flush()) {
+        qCWarning(lcIO) << "could not keep a dropped picture:" << file.errorString();
+        // A failed flush fails `remove()` too: close, then unlink.
+        file.close();
+        QFile::remove(file.fileName());
+        return std::nullopt;
+    }
+    return QUrl::fromLocalFile(file.fileName());
+}
+}
+
+bool ImageFileDrop::holdsImages(const QMimeData &data)
+{
+    for (const QUrl &url : data.urls())
+        if (url.isLocalFile())
+            return true;
+    return !pictureFormats(data).isEmpty();
+}
+
+std::vector<std::shared_ptr<QMimeData>> ImageFileDrop::providers(const QMimeData &data)
+{
+    std::vector<std::shared_ptr<QMimeData>> each;
+    const QList<QUrl> urls = data.urls();
+    if (std::any_of(urls.begin(), urls.end(), [](const QUrl &url) { return url.isLocalFile(); })) {
+        for (const QUrl &url : urls) {
+            auto provider = std::make_shared<QMimeData>();
+            provider->setUrls({url});
+            each.push_back(provider);
+        }
+        return each;
+    }
+    // No file: a picture with its address is one item.
+    auto whole = std::make_shared<QMimeData>();
+    // Swift asks for the preferred picture alone.
+    const QStringList formats = pictureFormats(data);
+    if (!formats.isEmpty())
+        whole->setData(formats.first(), data.data(formats.first()));
+    each.push_back(whole);
+    return each;
+}
+
+void ImageFileDrop::importProviders(const QMimeData &data, EditorSession &session, std::optional<QPointF> point, ProjectWorkspace *workspace,
+                                    std::optional<QUuid> destination, std::function<void()> done)
+{
+    QList<QUrl> urls;
+    bool unreadable = false;
+    for (const QUrl &url : data.urls()) {
+        if (url.isLocalFile())
+            urls << url;
+        else
+            unreadable = true;
+    }
+    // Not a file on disk: a browser's or screenshot's picture.
+    if (urls.isEmpty()) {
+        const std::optional<QUrl> copy = temporaryFile(data);
+        unreadable = !copy;
+        if (copy)
+            urls << *copy;
+    }
+    const auto finished = [&session, unreadable, done] {
+        if (unreadable) {
+            const QString message = QStringLiteral("Some dropped items couldn’t be read. Drag JPEG, PNG, HEIC, or TIFF files from the file manager.");
+            session.setImportError(session.importError() ? *session.importError() + QStringLiteral("\n\n") + message : message);
+        }
+        if (done)
+            done();
+    };
+    if (workspace)
+        workspace->receive(urls, destination, point, finished);
+    else
+        session.importImages(urls, point, finished);
+}