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>

tests/BlendShortcutTests.cpp

@@ -0,0 +1,52 @@
+#include "Rendering/EditorCanvas.h"
+#include "UI/NativeLayerList.h"
+#include <QLineEdit>
+#include <QtTest>
+
+// Shift-+ and Shift-− step the blend mode wherever focus sits.
+class BlendShortcutTests : public QObject {
+    Q_OBJECT
+private slots:
+    void shiftPlusAndMinusStepTheActiveLayersBlendModeWhereverFocusIsExceptTextFields();
+};
+
+void BlendShortcutTests::shiftPlusAndMinusStepTheActiveLayersBlendModeWhereverFocusIsExceptTextFields()
+{
+    EditorSession session;
+    session.createDocument(40, 20);
+    session.addBlankLayer();
+    QWidget window;
+    auto *canvas = new CanvasView(session, &window);
+    canvas->setGeometry(0, 0, 300, 200);
+    auto *list = new NativeLayerList(session, &window);
+    list->setGeometry(300, 0, 200, 200);
+    auto *field = new QLineEdit(&window);
+    field->setGeometry(0, 210, 100, 22);
+    window.resize(500, 240);
+    window.show();
+    QVERIFY(QTest::qWaitForWindowActive(&window));
+    const auto mode = [&] { return session.activeLayer().value().blendMode; };
+    session.selectTool(NavigationTool::brush);
+    canvas->setFocus();
+    QTRY_VERIFY(canvas->hasFocus());
+    QTest::keyClick(canvas, Qt::Key_Plus, Qt::ShiftModifier);
+    QCOMPARE(mode(), LayerBlendMode::multiply);
+    // From the list, back past Normal to the last mode.
+    session.selectTool(NavigationTool::lasso);
+    list->setFocus();
+    QTRY_VERIFY(list->hasFocus());
+    QTest::keyClick(list, Qt::Key_Underscore, Qt::ShiftModifier);
+    QTest::keyClick(list, Qt::Key_Underscore, Qt::ShiftModifier);
+    QCOMPARE(mode(), LayerBlendMode::luminosity);
+    session.undo();
+    QCOMPARE(mode(), LayerBlendMode::normal);
+    // Typing in a text field keeps its characters.
+    field->setFocus();
+    QTRY_VERIFY(field->hasFocus());
+    QTest::keyClick(field, Qt::Key_Plus, Qt::ShiftModifier);
+    QCOMPARE(mode(), LayerBlendMode::normal);
+    QCOMPARE(field->text(), QString("+"));
+}
+
+QTEST_MAIN(BlendShortcutTests)
+#include "BlendShortcutTests.moc"