New Canvas presets in a More menu; every save writes QuickLook/Preview.jpg (13.7)

tests/QuickLookPreviewTests.cpp

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+#include "DialogDesk.h"
+#include "IO/ImageExporter.h"
+#include "IO/ProjectController.h"
+#include "ProjectFixtures.h"
+#include <QBuffer>
+#include <QColorSpace>
+#include <QImageReader>
+#include <QImageWriter>
+#include <QTemporaryDir>
+#include <QtTest>
+
+// The project's QuickLook/Preview.jpg: written on save, ignored on load.
+namespace {
+const QDir::Filters everything = QDir::AllEntries | QDir::NoDotAndDotDot | QDir::Hidden;
+
+// One layer stretched over a canvas of this size.
+ProjectSnapshot stretched(int width, int height, const QImage &pixels)
+{
+    const QUuid id = QUuid::createUuid();
+    const ProjectLayerRecord layer{.id = id, .name = "Stretched", .isVisible = true,
+                                   .transform = {.origin = {0, 0}, .size = {double(width), double(height)}}, .imageFile = uuidString(id) + ".png"};
+    return {.manifest = {.documentID = QUuid::createUuid(), .width = width, .height = height, .activeLayerID = id, .layers = {layer}},
+            .images = {{id, asset(pixels, "source")}}};
+}
+
+QImage decoded(const QByteArray &data)
+{
+    QImage image = QImage::fromData(data, "jpeg");
+    if (image.isNull())
+        throw std::runtime_error("the preview is no JPEG");
+    return image;
+}
+
+QSize previewSize(int width, int height)
+{
+    QImage empty(1, 1, QImage::Format_RGBA8888_Premultiplied);
+    empty.fill(0);
+    return decoded(ImageExporter::quickLookImages(stretched(width, height, empty)).value().preview).size();
+}
+}
+
+class QuickLookPreviewTests : public QObject {
+    Q_OBJECT
+private slots:
+    void theStoreWritesThePreviewAndLoadingIgnoresIt();
+    void thePreviewIsTheImageOnWhiteAtQualityEighty();
+    void theLongSideIsAt1024AndNothingGrows();
+    void pastFiftyMegapixelsThereIsNone();
+    void aCanvasThatCannotRenderSavesWithoutOne();
+    void everySaveWritesIt();
+};
+
+void QuickLookPreviewTests::theStoreWritesThePreviewAndLoadingIgnoresIt()
+{
+    QTemporaryDir root;
+    const QString path = root.filePath("Previewed.comp");
+    const ProjectSnapshot snapshot = twoLayers();
+    ProjectStore::save(snapshot, path, QuickLookImages{"not even a JPEG"});
+    QCOMPARE(QDir(path).entryList(everything), (QStringList{"images", "manifest.json", "QuickLook"}));
+    QCOMPARE(QDir(path + "/QuickLook").entryList(everything), QStringList{"Preview.jpg"});
+    QCOMPARE(contents(path + "/QuickLook/Preview.jpg"), QByteArray("not even a JPEG"));
+    // Its bytes are never read.
+    QCOMPARE(ProjectStore::load(path).manifest.encoded(), snapshot.manifest.encoded());
+    // Saved without one, the project has none.
+    ProjectStore::save(snapshot, path);
+    QCOMPARE(QDir(path).entryList(everything), (QStringList{"images", "manifest.json"}));
+    QCOMPARE(ProjectStore::load(path).manifest.encoded(), snapshot.manifest.encoded());
+}
+
+void QuickLookPreviewTests::thePreviewIsTheImageOnWhiteAtQualityEighty()
+{
+    // Half opaque red, half clear, over 2048 by 1024.
+    const ProjectSnapshot snapshot = stretched(2048, 1024, halfRed());
+    const QByteArray preview = ImageExporter::quickLookImages(snapshot).value().preview;
+    const QImage image = decoded(preview);
+    QCOMPARE(image.size(), QSize(1024, 512));
+    QVERIFY(qAbs(image.pixelColor(200, 256).red() - 255) <= 3 && image.pixelColor(200, 256).green() <= 3);
+    QCOMPARE(image.pixelColor(800, 256), QColor(Qt::white));
+    // Byte for byte: smooth scaling, white, quality 80, 72 dpi.
+    const QImage scaled = ImageExporter::render(snapshot).image.scaled(1024, 512, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+    QImage flattened(1024, 512, QImage::Format_RGB888);
+    flattened.fill(Qt::white);
+    QPainter(&flattened).drawImage(QRectF(flattened.rect()), scaled);
+    flattened.setDotsPerMeterX(2835);
+    flattened.setDotsPerMeterY(2835);
+    flattened.setColorSpace(QColorSpace::SRgb);
+    QByteArray expected;
+    QBuffer buffer(&expected);
+    QImageWriter writer(&buffer, "jpeg");
+    writer.setQuality(80);
+    QVERIFY(writer.write(flattened));
+    QCOMPARE(preview, expected);
+}
+
+void QuickLookPreviewTests::theLongSideIsAt1024AndNothingGrows()
+{
+    QCOMPARE(previewSize(300, 200), QSize(300, 200));
+    QCOMPARE(previewSize(1024, 7), QSize(1024, 7));
+    QCOMPARE(previewSize(1025, 1025), QSize(1024, 1024));
+    // 1001 × 1024 / 3000 is 341.67: rounded, not cut.
+    QCOMPARE(previewSize(3000, 1001), QSize(1024, 342));
+    QCOMPARE(previewSize(10, 5000), QSize(2, 1024));
+    // A sliver keeps a pixel.
+    QCOMPARE(previewSize(1, 3000), QSize(1, 1024));
+    QCOMPARE(previewSize(3000, 1), QSize(1024, 1));
+}
+
+void QuickLookPreviewTests::pastFiftyMegapixelsThereIsNone()
+{
+    QImage empty(1, 1, QImage::Format_RGBA8888_Premultiplied);
+    empty.fill(0);
+    QVERIFY(!ImageExporter::quickLookImages(stretched(7072, 7071, empty)));
+    QCOMPARE(decoded(ImageExporter::quickLookImages(stretched(10'000, 5'000, empty)).value().preview).size(), QSize(1024, 512));
+}
+
+void QuickLookPreviewTests::aCanvasThatCannotRenderSavesWithoutOne()
+{
+    ProjectSnapshot snapshot = twoLayers();
+    snapshot.images.clear();
+    QTest::ignoreMessage(QtWarningMsg, "no Quick Look preview: An image inside the project is missing or damaged. The current document has not been replaced.");
+    QVERIFY(!ImageExporter::quickLookImages(snapshot));
+}
+
+void QuickLookPreviewTests::everySaveWritesIt()
+{
+    QTemporaryDir folder;
+    EditorSession session;
+    session.createDocument(8, 6);
+    QImage image(8, 6, QImage::Format_RGBA8888_Premultiplied);
+    image.fill(Qt::blue);
+    session.insert(ImportedImage(image, QImage(), "Blue"));
+    ProjectController controller(session);
+    DialogDesk desk;
+    desk.replies = {folder.filePath("Saved")};
+    bool saved = false;
+    controller.save(false, [&](bool done) { saved = done; });
+    QTRY_VERIFY(saved);
+    const QImage preview = decoded(contents(folder.filePath("Saved.comp/QuickLook/Preview.jpg")));
+    QCOMPARE(preview.size(), QSize(8, 6));
+    QVERIFY(preview.pixelColor(4, 3).blue() >= 250 && preview.pixelColor(4, 3).red() <= 5);
+}
+
+QTEST_MAIN(QuickLookPreviewTests)
+#include "QuickLookPreviewTests.moc"